NEURODIAGNOSTIC TESTING (Step 3 Revision)

Discussion in 'Step 3' started by Guest, Nov 8, 2008.

  1. Guest

    Guest Guest

    NEURODIAGNOSTIC TESTING

    Lumbar Puncture (LP)
    Most often performed in the L3 or L4 interspaces (at the level of the superior iliac crests). The needle is advanced to the subarachnoid space.
    Opening pressure should be measured but is valid only when obtained with the patient in the lateral decubitus position (i.e., with the spinal needle located at the same level as the heart).
    Patients with papilledema, focal neurologic signs, or immunosuppression should have imaging prior to LP to evaluate for mass effect and herniation risk. Imaging of the spine should precede LP in patients with spinal cord signs or symptoms.

    Electroencephalography (EEG)
    Conditions with notable EEG findings include the following:
    Metabolic encephalopathy: Hepatic encephalopathy is the classic metabolic coma. EEG typically shows generalized periodic triphasic waves.
    Viral encephalitis:
    HSV encephalitis: The classic EEG finding consists of periodic lateralizing epileptiform discharges (PLEDs) originating over one or both temporal lobes.
    Subacute sclerosing panencephalitis (SSPE): EEG typically shows a flat background punctuated by periodic generalized large-amplitude slow-wave discharges.
    Prion disease: EEGs in patients with Creutzfeldt-Jakob disease show periodic generalized sharp waves

    Computed Tomography (CT)
    CT imaging of the brain is inferior to MRI for most studies but is the imaging study of choice for investigating acute hemorrhage (e.g., SAH, epidural hematoma) and bone pathology (e.g., skull or vertebral fractures).

    Magnetic Resonance Imaging (MRI)
    The best imaging modality for most diseases of the brain and spinal cord, including neoplastic, vascular, demyelinating, infectious, and structural diseases (e.g., spondylosis of the spine).
    Cerebral Angiography
    The gold standard for investigating vascular abnormalities of the CNS, including stenosis, aneurysms, AVMs, and cerebral vasculitis. Also useful for preoperative evaluation of vascular supply to intracranial tumors (e.g., meningiomas).
    Cerebral venography is the gold standard for diagnosing venous sinus thrombosis.

    Evoked Potentials (EPs)
    Obtained by measuring the time course of a specific CNS response to a given stimulus.
    Visual EPs are generated by recording cortical response (using EEG electrodes) elicited by a visual stimulus. A delay in response suggests that the conduction velocity along the visual pathway is slow, often a sign of demyelination (e.g., in MS).
    Brain stem and sensory EPs are useful for evaluating potential demyelinating lesions of the brain stem and dorsal columns of the spinal cord. Often used to obtain supportive evidence of CNS demyelination.
    Sensory and motor EPs are used for intraoperative monitoring during neurosurgical procedures involving the spinal cord or brain stem and can be helpful prognostically in hypoxic-ischemic encephalopathy.
  2. Guest

    Guest Guest

    HEADACHE

    All patients presenting with headache merit a detailed history and neurologic evaluation, including a funduscopic exam for papilledema.
    The evaluation of headache should be thorough, and this consists of a complete history, thorough physical examination, and laboratory workup. Neurological imaging (CT or MRI) is not required unless there exist abnormal, unexplainable findings on the neurologic examination, the ehadaches are worsening despite appropriate therapy, the headaches are reported as extremely severe, especialy in patients older than 40 years.
    Migraine Headache
    Most patients are young women (the female-to-male ratio is 3:1). Ninety percent of patients have a strong family history.
    Benign, recurrent headaches that classically produce unilateral pulsating pain associated with symptoms such as photophobia, phonophobia, anorexia, nausea, and vomiting.
    Episodes typically last 4–72 hours, and patients often report improvement with resting in a dark, quiet room.
    Subtypes are as follows:
    Classic migraine (migraine with aura): Occurs in 20% of patients.
    The most common auras are visual, including “fortification spectra†and scotomas (blind spots).
    Common migraine: Most migraine patients do not have preceding auras.
    Migraine variants: Named for associated focal neurologic deficits and/or vascular territories; include hemiplegic migraine, basilar migraine (brain stem symptoms such as ataxia, vertigo, and slurred
    speech), and ophthalmoplegic migraine (unilateral CN III palsy and pupillary abnormality).
    Patients with classic and common migraines have normal neurologic exams.
    In patients with headache and focal neurologic deficits, a migraine variant remains a diagnosis of exclusion. These patients require workup for other causes of headache and focal deficits (e.g., vascular event, infection, intracranial mass).
    Management is divided into two categories: abortive therapy for the migraine itself (taken only at the time of the migraine) and prophylactic therapy for preventing future attacks (taken daily).
    Prophylactic therapy is given only to patients with frequent severe migraines and includes TCAs (e.g., amitriptyline), β-blockers (e.g., propranolol), calcium channel blockers (e.g., verapamil), and antiseizure medications (e.g., valproic acid, topiramate). If patient has BA give amitryptiline.
    Abortive therapy includes the following:
    Vasoconstrictors:
    Triptans: 5-HT1 serotonin receptor agonists (e.g., sumatriptan, frovatriptan, eletriptan, naratriptan, almotriptan, rizatriptan, zolmitriptan) produce vasoconstriction. Do not use in patients with vascular disease (e.g., CAD, peripheral vascular disease) or in pregnant women.
    Ergotamines: Also to be avoided in patients with vascular disease and in pregnant women.
    Others:
    Acetaminophen/butalbital/caffeine (Fioricet): Butalbital is a barbiturate and has addictive properties.
    Isometheptene/dichloralphenazone/acetaminophen (Midrin): Avoid in patients taking MAOIs.
    Antiemetics: Prochlorperazine, promethazine.
    Always start with NSAIDs than give acetomenophen, if that didn’t work either than give ergotamine.
    Cluster Headache
    Classically occurs in young men 20–40 years of age (the male-to-female ratio is 5:1). A family history of similar headaches is uncommon.
    The cardinal feature is periodicity. Headaches occur many times daily at distinct times over several weeks; onset with sleep is especially characteristic.
    Clusters spontaneously remit for months to years before recurring, typically at the same time of year as previous attacks. Alcohol is a classic trigger.
    Cluster headaches do not have auras (vs. migraines). A typical attack is characterized by abrupt-onset, severe unilateral periorbital pain with associated ipsilateral autonomic symptoms (tearing of the eye and nares, sweating and pallor; rarely Horner’s). Headaches typically last 30–120 minutes.
    As with migraines, treatment includes abortive and prophylactic therapies.
    Prophylactic medications are started once cluster headaches begin but are not used during remissions given that months to years may elapse between clusters. Such medications include verapamil (first-line prophylactic treatment for cluster headache), lithium (direct comparison to CCBs showed that both are equaly effective , but verapamil has better side effecs profile), prednisone (a taper of oral steroids is often used at the beginning of a cluster, long term use is not recommended due to side effects), valproate, and methysergide.
    Abortive therapy includes the following:
    O2 inhalation: Give 5–10 L/min for 10–15 minutes.
    Intranasal lidocaine ointment: Produces a block of the sphenopalatine ganglion and aborts the headache.
    Triptans: Also useful for acute attacks.

    Tension Headache
    The most common type of recurring headache.
    Presents as a bilateral headache with pain in the frontal and occipital regions in a bandlike distribution.
    Exacerbated by stress, fatigue, glare, or noise as they tend to occur on weekdays. Often involves contraction of the scalp and posterior neck muscles. There are no associated nausea and vision problems.
    Neurologic exam is normal.
    Dx: Based on the history and lack of neurologic findings.
    Tx:
    Acute headache: Aspirin, NSAIDs, ergotamines.
    Prophylaxis: TCAs, SSRIs, β-blockers, relaxation techniques.
    Cx: Risk of rebound headaches with frequent analgesic use.

    Trigeminal Neuralgia (Tic Douloureux)
    A unilateral facial pain syndrome affecting middle-aged and elderly patients.
    Most commonly occurs in the sixth decade. Onset in young patients should raise suspicion for an underlying disorder (e.g., MS, brain stem neoplasm).
    Characterized by abrupt-onset, short-duration (seconds) episodes of severe unilateral lancinating electrical pain, typically radiating along the jaw in the distribution of the second and third divisions of CN V (the trigeminal nerve). Attacks are often triggered by sensory stimuli to the face (e.g., touch, wind, shaving, chewing).
    Neurologic exam is normal. Any abnormalities on exam, including sensory loss of the face in the distribution of the pain, suggests an alternative diagnosis and mandates further evaluation (e.g., imaging, LP).
    At surgery or autopsy, intracranial arterial and, less often, venous loops compressing the trigeminal nerve root where it enters the brain stem have been found, suggesting that the tic is a compressive neuropathy.
    Carbamazepine is first-line therapy. Alternatives include oxcarbazepine, valproate, phenytoin, baclofen, gabapentin, and benzodiazepines.

    Idiopathic Intracranial Hypertension (Pseudotumor Cerebri)
    A headache syndrome related to chronically elevated ICP. Classically seen in young, obese women. Associations have been noted with medications (tetracycline derivatives, steroids, vitamin A, danazol, tamoxifen, levothyroxine, cimitidine, lithium, nitrofurontoin), endocrine disorders ( hyperparathyroidism, hypothyroidism, adrenal insufficiency, Cushing disease) as well as with disorders such as SLE, Behçet’s syndrome, and uremia.
    Patients usually note a progressive global headache that worsens when they lie flat, often worsening at night and upon awakening. Exacerbated by maneuvers that elevate ICP (e.g., Valsalva, cough, sneeze).
    Elevated ICP can produce transient visual obscurations (blurring or blackout of vision in either or both eyes for seconds), double vision from CN VI palsies, and/or progressive loss of peripheral vision. Total blindness can result.
    Papilledema is the key finding. Patients may also have ↓ visual acuity and/or loss of peripheral vision. CN VI palsies may result from elevated ICP.
    Following are criteria for DX:1-Presence of features of ICP in an alert pt. 2-Absence of focal neuro signs except 6th nerve palsy. 3-Normal CSF exept icreased opening presure. 4-Absence of any ventricular abnormality other than enlagement caused by ICP.
    Patients with headache and papilledema should first undergo brain imaging, preferably with MRI. In patients with pseudotumor, MRI is normal, including ventricular size. Most pt have empty sella in CT. MR venography to exclude venous sinus thrombosis.
    LP should be performed with the patient in the lateral decubitus position, with pressure measured after the patient’s legs are extended and relaxed. LP reveals an opening pressure > 200 mm H2O, normal protein and glucose, and no cells.
    TX: Based on lowering ICP. Acetazolamide, a carbonic anhydrase inhibitor that reduces CSF production and ICP, is first-line therapy. Lasix can also be used.
    Serial LPs, optic nerve fenestration, and permanent shunting of CSF are used for refractory cases.
    Weight loss is an important component of management in most patients.
    Serial ophthalmologic evaluation is mandatory for these patients, as visual loss can be severe and permanent.

    Medication Rebound Headache
    Overuse of analgesic medications for headache syndromes (e.g., narcotics, triptans, ergotamines, barbiturates) can paradoxically produce refractory chronic daily headaches. Prophylactic medications are ineffective until patients have been weaned off the offending analgesic medications. Often requires
    a slow taper of the analgesic to prevent withdrawal symptoms.
  3. Guest

    Guest Guest

    Post-traumatic Headache

    Commonly occurs following minor head injuries or hyperextension- flexion injuries (“whiplashâ€Â). Usually resolves in weeks to months.
    Presents with a generalized constant headache associated with impaired attention, concentration, and memory. Onset is < 2 weeks from trauma.
    Symptoms may become persistent within several weeks of injury. Acute cases last < 8 weeks. Chronic post-traumatic headache lasts > 8 weeks.
    Dizziness, nausea, irritability, insomnia, and ↓ light and sound tolerance may also be seen.
    Neurologic exam is typically normal.
    Dx: Based on the history and a normal neurologic exam with a normal head CT and LP (if performed).
    Tx: Supportive care; pain management.
    Antiemetics and TCAs may be of benefit.

    Temporal Arteritis (Giant Cell Arteritis)
    A treatable neurologic emergency characterized by subacute inflammation of the external carotid arterial system and vertebral arteries. Most cases occur in women > 50 years of age.
    Presents with temporal or diffuse headache unlike any the patient has had before, along with transient visual loss, scalp tenderness, jaw claudication, fever, myalgia, malaise, anorexia, weight loss, tenderness, and stiffness in the shoulders and hips.
    On exam, the temporal arteries may be dilated, tender, thickened, and nonpulsatile.
    Funduscopic exam may reveal a pale optic disk on the affected side. Cranial neuropathies are common.
    DD: Glaucoma, uveitis, rheumatoid arthritis (RA), trigeminal neuralgia, retinal
    embolism, Takayasu’s arteritis.
    Diagnosis is guided by the history and exam. History may reveal coexisting
    polymyalgia rheumatica.
    Biopsy of affected temporal arteries shows vasculitis with mononuclear cell infiltration or granulomatous inflammation.
    An ESR > 50 mm/hr is common (although rare cases may show a normal ESR). Normochromic, normocytic anemia with thrombocytosis is also common.
    TREATMENT
    Prednisone 60 mg daily for 1–2 months with slow taper and monitoring of symptoms and ESR. Aspirin ↓ the risk of stroke or visual loss.
    Fifty percent of untreated patients suffer permanent visual loss, with half experiencing bilateral loss. Temporal arteritis is also associated with a risk of cranial neuropathy, TIA, stroke, and thoracic aortic aneurysm.

    Intracranial Arteriovenous Malformation (AVM)
    Congenital abnormal connections between arterioles and venules without intervening capillaries. Usually discovered on hemorrhage of the malformation or related aneurysm. Most are supratentorial and are found by age 40.
    Presents with persistent generalized or stereotyped unilateral headaches or seizure. Neurologic exam is usually normal without hemorrhage but may show progressive focal neurologic signs.
    Hemorrhage may be accompanied by an abnormal mental state, signs of meningeal irritation, seizure, signs of ↑ ICP, hemiparesis or paralysis, aphasia, and ↓ sensation.
    Obtain an MRI/MRA. EEG for patients with seizure; head CT if hemorrhage is suspected.
    Perform an LP to examine CSF for blood if hemorrhage is suspected and CT is not diagnostic.
    Arteriography if hemorrhage, aneurysm, or AVM is detected or if the source remains unclear.
    TREATMENT
    Stop any anticoagulant or antiplatelet medications.
    Anticonvulsants for seizure activity.
    Neurosurgery for hemorrhage in patients with a reasonable life expectancy and an accessible lesion. Embolization or polymer occlusion of surgically inaccessible lesions.
    COMPLICATIONS
    Headaches, hemorrhage, focal neurologic deficits, seizures, hydrocephalus.

    Headaches classics
    To correcly diagnose and treat patients with chronic headaches, the characteristics of the headaches must be clarified. Such patients should be instructed to make headache diary for one week, and this should include the heaaches frequency, duration, intenisty, associated symptoms and medications used.

    SYMPTOM
    POSSIBLE CAUSE

    Sudden onset of “the worst headache of my life†SAH.
    Neck stiffness with severe headache Bacterial meningitis.


    Sudden ↓ level of consciousness Intracranial bleed, intracranial mass.

    Progressively worsening headache Intracranial mass.
    Daily headaches that awaken the patient from sleep or are severe on arising in the morning
    Intracranial mass with ↑ ICP. (Mig common cause of morning headache.)

    Onset of headaches after age 30 Intracranial mass.

    Progressive visual, motor, or balance disturbance Intracranial mass, vascular lesion.

    Onset of headache after age 50 Temporal arteritis, intracranial mass.
  4. Guest

    Guest Guest

    MULTIPLE SCLEROSIS (MS)

    An autoimmune inflammatory disease affecting the myelin of the CNS. Characterized by focal demyelinating plaques that occur at different times and locations within the CNS. Typically affects the optic nerves, corpus callosum, periventricular white matter, brain stem, and spinal cord. Generally seen in
    younger women. Incidence ↑ with latitude of birth and is twice as high in patients of Northern European descent as in patients of African descent. In addition to focal abnormalities, patients often suffer from chronic fatigue.
    Symptoms are exacerbated by heat and exercise (the Uhthoff phenomenon); old deficits may also be worsened by underlying illness, especially infections such as UTIs or URIs.
    Classic lesions and exam findings include the following:
    Optic nerve: Optic neuritis presents as unilateral subacute vision loss associated with pain with eye movement. Exam shows pallor of the optic nerve (may be normal in the acute setting), ↓ visual acuity, difficulty with color discrimination, and a relative afferent pupillary defect (RAPD, or
    Marcus Gunn pupil).
    Brain stem: A demyelinating lesion of the medial longitudinal fasciculus yields an internuclear ophthalmoplegia. Patients complain of double vision when looking to one side; exam reveals inability to adduct the eye ipsilateral to the lesion during voluntary horizontal gaze. Adduction of the eye can be brought out by testing convergence, which remains normal
    Spinal cord: Transverse myelitis symptoms (paresthesias, sensory level, bowel/bladder dysfunction, UMN signs) are common.
    Lhermitte’s sign (electrical radiation down the spine elicited by neck flexion) is a classic finding and is likely related to dorsal column involvement.
    Clinical criteria: No laboratory or imaging test is diagnostic for MS, and thus the diagnosis must be based on clinical criteria. Definitive diagnosis requires evidence from the history and exam of at least two distinct attacks involving two separate CNS regions. Imaging and laboratory data support the diagnosis.
    MRI: MRI abnormalities are seen in > 90% of patients. Most have multiple punctate/ovoid lesions involving the periventricular white matter (“Dawson’s finger†lesions extending from the ventricles at right angles), corpus callosum, brain stem, and spinal cord. These are best seen on T2- weighted images. Acute “active†lesions enhance with gadolinium contrast.
    MRI is the test of choice (most sensitive) and is diagnostic in the majority of cases.
    Now considered standard of care
    Sensitive in identifying demyelinating lesions in CNS
    The number of lesions on the MRI is not necessarily proportional to disease severity or speed of progression.
    MRI is the imaging modality of choice for MS, but it is used only to support the clinical diagnosis.
    CSF: Typical findings include normal opening pressure, mild lymphocytic pleocytosis (5–40 WBCs/mm3), normal glucose, and normal to mildly ↑ protein. Eighty percent of patients have > 2 oligoclonal bands and an elevated CSF IgG index, but neither is specific for MS.
    EPs: Occasionally used to obtain supportive evidence of demyelination if MRI and CSF results are inconclusive. For evaluation of MS, visual Eps are often used.
    Consider MS in a young patient presenting with any of the following: subacute loss of vision; double vision when looking to one side; an electrical sensation running down the spine when the neck is flexed; subacute spinal cord symptoms (e.g., paresthesias and bowel/bladder dysfunction); and worsening of neurologic symptoms with heat or exercise.
    Diagnostic tests for MS (helpful hints)
    MRI is abnormal in 90% of MS patients.
    CSF is abnormal in 90% of MS patients.
    Evoked potentials are abnormal in 90% of MS patients (used to identify silent lesions).



    Clinically Definite MS
    Two episodes of symptoms
    Evidence of two white matter lesions (imaging or clinical)
    Laboratory-Supported Definite MS
    Two episodes of symptoms
    Evidence of at least one white matter lesion on MRI
    Abnormal CSF (oligoclonal bands in CSF)
    TREATMENT
    Treatment of acute attacks
    High-dose IV corticosteroids can shorten an acute attack. Oral steroids have not shown the same efficacy.
    Studies have shown that treatment of acute exacerbations does not alter the outcome or course of MS.
    Most acute attacks resolve within 6 weeks with or without treatment.
    One study showed therapeutic plasma exchange (TPE) for steroid-refractory acute demyelinating attacks had a 42% response rate.
    Disease-modifying therapy
    Disease-modifying therapies include the following:
    β-interferon and glatiramer acetateâ€â€Ã¢â‚¬Å“ABC drugs†(Avonex, Betaseron, Copaxone): These drugs have been shown to ↓ the frequency and severity of relapses in patients with relapsing-remitting MS.
    Interferon therapy should be started early in the course of disease before the disability becomes irreversible. The best way to to monitoring the disease activity is with repeat MRI scan three months after the initial scan.
    Nonspecific immunosuppressive therapy such as cyclophosphamide should be reserved for rapidly progressive disease, because toxic side effects are many.
    Glucocorticoids: High-dose IV glucocorticoids (Solu-Medrol 1 g IV QD × 3–5 days), which are typically used to treat acute attacks and the presence of new enhancing lesions on MRI, appear to be superior to oral steroids (especially for treating optic neuritis) in leading to faster recovery. However, the administration of glucocorticoids has no impact on overall disease progression or long-term disability.
    Specific symptoms are targeted with appropriate medications:
    Hyperreflexic bladder: Oxybutynin.
    Fatigue: Amantadine, modafinil.
    Paroxysmal symptoms (e.g., tonic spasms): Carbamazepine.
    Spasticity: Baclofen, diazepam.
    Prognosis: onset at an early age, female sex, and relapsing type of disease ïƒ better prognosis
    Patient who initial present with sensory symptoms or cranial nerve involvement (esp optic neuritis) have a favourable prognosis too.
    Initial presentation due to involvement of the cerebellum, brainstem or pyramidal system ïƒ poor prognosis
    MS and pregnancy:
    Relapses are decreased during pregnancy and increased in postpartum.contraception is important if patients are taking disease modifying agents: however, therapeutic abortion is not indicated if the bocome pregnant with early exposure (stop the medication and reffer to OBS for fetal monitoring).
    Vaccination with Hep B is not a risk for MS relapse.
  5. Guest

    Guest Guest

    NEUROMUSCULAR JUNCTION DISORDERS

    Myasthenia Gravis (MG)
    An autoimmune disorder that is usually caused by autoantibodies to the nicotinic ACh receptor (nAChR), resulting in impaired transmission at the neuromuscular junction. Occurs in young women (ages 20–30) and older men (ages 50–70). Associated with other autoimmune diseases, particularly thyroid disorders.
    The hallmark is fluctuating, fatigable weakness classically affecting the eye muscles. There are two forms: (1) ocular, which is isolated to the extraocular and eyelid muscles, giving double vision and ptosis; and (2) generalized, which typically involves ocular, facial, and proximal limb muscles, giving rise to ocular symptoms as well as to facial weakness, trouble swallowing and speaking, respiratory dysfunction, and limb weakness. Patients with ocular MG may progress to generalized MG.
    Symptoms worsen as day progresses. (This is the opposite of rheumatoid arthritis.)
    Ptosis, often asymmetric, can be brought out by testing prolonged upgaze; an ice pack briefly placed on the eye will improve ptosis.
    Extraocular muscle palsies are typically seen on lateral gaze.
    Easy fatigability of proximal muscles with repeated strength testing.
    Preserved DTRs and sensation.
    DIFFERENTIAL
    Lambert-Eaton myasthenic syndrome.
    Drug-induced MG: Penicillamine can cause a reversible antibody + MG syndrome (test of choice).
    Botulism: Typically presents with cranial nerve palsies, including the extraocular muscles. Patients have CSF pleocytosis and often absent reflexes.
    Anti-nAChR antibodies: Present in > 80% of generalized MG and 50% of ocular MG cases.
    Anti-MuSK antibodies: Present in 20% of “seronegative†MG patients.
    EMG/NCS: Direct testing of the muscle with EMG/NCS remains the best test for MG. Repetitive nerve stimulation reveals a decremental motor response, the correlate of clinical fatigability.
    A CT scan of the thorax can rule out thymoma. Thymoma is present in only 10% to 15% of patients, but the thymus is histologically abnormal in 75% of patients.
    Tensilon test: Tensilon (edrophonium), a short-acting AChE inhibitor, can give instantaneous improvement to an objectively weak muscle (High false positive rates). Caution must be used, as it may precipitate cardiac arrhythmias.
    TREATMENT
    AChE inhibitors: Include pyridostigmine.
    Inhibiting AChE increases concentration of acetylcholine at the synapse by decreasing the breakdown of acetylcholine.
    This is a symptomatic benefit only.
    Immunomodulators:
    Use corticosteroids for patients with a poor response to AChE inhibitors.
    Prednisone as first line therapy
    Cyclosporine or azathioprine if prednisone not effective
    Plasmapheresis removes antibodies to acetylcholine receptors. Use it if all else fails or if the patient is in respiratory failure.
    IV immunoglobulin therapy is now sometimes used for acute exacerbations.
    Monitor serial forced vital capacities. A forced vital capacity of 15 mL/kg (about 1 L) is generally an indication for intubation. Patients in myasthenic crisis have a low threshold for intubationâ€â€do not wait until the patient is hypoxic.
    Thymectomy: Patients require chest imaging to evaluate for thymic abnormalities, as 70% have hyperplasia and 10% have thymomas. Thymectomy is recommended for most patients < 60 years of age with generalized MG.
    This provides a symptomatic benefit and complete remission in many patients, even in the absence of a thymoma.
    Although usually benign, thymoma is an absolute indication for thymectomy.
    Myasthenic crisis: Elective intubation if FVC falls < 15 mL/kg.
    Patients in crisis should get steroids, PFTs, ICU admission, but not acetylcholinesterase inhibitors until crisis is under control.
    COMPLICATIONS
    Often exacerbated by stress, fever, infections, and certain medications, including antibiotics (especially aminoglycosides, Aminoglycosides can precipitate myasthenic crisis), as well as by antiarrhythmics such as procainamide and β-blockers.
  6. Guest

    Guest Guest

    Lambert-Eaton Myasthenic Syndrome (LEMS)

    An autoimmune (sometimes paraneoplastic) syndrome caused by autoantibodies to presynaptic voltage-gated calcium channels, leading to impaired transmission at the neuromuscular junction. Typically seen in men and women > 40 years of age. More than half have an underlying malignancy, with the majority being small cell lung cancer.
    Presents with proximal muscle weakness, especially in the legs, that briefly improves with exertion before eventually fatiguing.
    Muscle aches are also seen, as are autonomic symptoms (dry mouth, impotence, constipation, postural hypotension).
    In contrast to MG, LEMS patients do not experience double vision or ptosis
    Normal cranial nerve exam; proximal weakness of the legs and arms that initially improves with repeated testing; hyporeflexia.
    EMG/NCS: Direct testing of the muscle with EMG remains the best test for LEMS. In contrast to MG, high-frequency repetitive nerve stimulation in LEMS reveals an initial enhancement of motor responses, the correlate of clinical improvement upon initial exertion.
    Neoplastic workup: Diagnosis of LEMS often precedes the diagnosis of cancer by a year or more. Initial evaluation should be directed at possible small cell lung cancer.
    TREATMENT
    1° treatment is directed at treating the underlying malignancy.
    3,4-diaminopyridine (DAP) may facilitate neuromuscular transmission but is difficult to obtain in the United States.
    IVIG and plasma exchange may improve symptoms
  7. Guest

    Guest Guest

    AMYOTROPHIC LATERAL SCLEROSIS (ALS)

    A progressive degenerative disease of the UMNs (arising in the motor cortex) and LMNs (arising in the brain stem and anterior horn of the spinal cord).
    Affects males and females equally, with onset between 50 and 70 years of age.
    Life expectancy is 3–5 years, with death usually occurring 2° to aspiration pneumonia or respiratory failure.
    Five to ten percent of cases are familial. One genetic cause is autosomal-dominant transmission of a mutation in the copper-zinc superoxide dismutase (SOD 1) gene on chromosome 21.
    Progressive muscle weakness is the hallmark feature.
    Usually first noted in the legs or arms, but then spreads to other muscle groups
    No associated pain
    Muscle atrophy
    Muscle cramps and spasticity
    Fasciculations (unnoticed by patient)
    Impaired speech and swallowing; dysphagia can lead to aspiration
    Respiratory muscle weaknessâ€â€dyspnea on exertion, and later, at rest; orthopnea; sleep apnea; end-stage ALS is characterized by respiratory failure
    Weight loss and fatigue
    The following are normal and unaffected, even in late stages.
    o Bowel and bladder control
    o Sensation
    o Cognitive function
    o Extraocular muscles
    Cognitive dysfunction in the form of frontotemporal dementia has been shown to be fairly common late in the disorder.
    Exam findings include both UMN and LMN signs.
    Signs of UMN injury: Spasticity (↑ muscle tone), hyperreflexia, Babinski sign.
    Signs of LMN injury: Atrophy (especially of the tongue and muscles of the hands); fasciculations (muscle twitches).
    EMG/NCS reveal evidence of widespread LMN injury (e.g., fibrillations, fasciculations) and UMN injury that does not fall in a nerve root distribution.
    Sensory nerve studies are normal.
    Spinal fluid analysis is normal.
    Cervical spine imaging to evaluate for the possibility of cervical spondylosis with cord compression, a surgically treatable disease.
    TREATMENT
    Riluzole, a presumed glutamate antagonist, is the only FDA-approved medication for ALS. Improves survival by approximately six months.
    Noninvasive positive-pressure ventilation improves survival and should be offered if FVC falls to < 50% predicted.
    Percutaneous endoscopic gastrostomy tube placement allows for ↑ nutrition in the face of dysphagia and leads to ↑ muscle mass and longer survival.

    NEUROPATHIES
    CHARACTER
    Peripheral nerves carry distinct fiber types: sensory, motor, and autonomic.
    Many disorders selectively attack specific fiber types, while others indiscriminately affect all types. The nature of symptoms depends on which fiber types are injured.
    Sensory nerves: Paresthesias (burning, numbness, tingling) are common initial symptoms, with overt sensory loss occurring with progression of disease.
    Motor nerves: Weakness, atrophy, twitching (fasciculations).
    Autonomic nerves: Postural hypotension, impotence, nausea, diarrhea, dry mouth.
    DISTRIBUTION
    Polyneuropathies: Result from diseases that affect multiple peripheral nerves in a diffuse and synchronous fashion. Many polyneuropathies are “length dependent,†affecting the longest nerves first. Produces the classic “stocking-glove†distribution of symmetric involvement of all four distal extremities.
    Mononeuropathies: Diseases of an individual peripheral nerve (e.g., radial nerve palsy), with symptoms restricted to its specific distribution.
    Mononeuritis multiplex: A unique syndrome in which multiple individual peripheral nerves are progressively injured in an asymmetric and asynchronous fashion.
    PATHOLOGY
    The location of injury in peripheral neuropathies involves either the axon or its insulating myelin covering. Identifying its location helps focus the differential and direct treatment.
    Axonal neuropathies are more likely metabolic in nature. As they involve direct injury to the nerve, recovery is often more limited and slow. NCS shows low amplitude.
    Demyelinating neuropathies are often inflammatory and thus treatable; as the neuron itself is not directly injured, recovery is often the rule as remyelination occurs. NCS shows slow conduction velocity.

    Acute Polyneuropathies
    GUILLAIN-BARRÉ SYNDROME (GBS)
    A postinfectious autoimmune acute demyelinating polyneuropathy. Given the decline of polio, it is now the most common cause of acute flaccid paralysis. GBS classically follows an acute GI illness caused by Campylobacter jejuni, as antibodies directed toward its bacterial lipopolysaccharide cross-react
    with peripheral nerve myelin; other infections (e.g., HIV, Mycoplasma) have also been associated with GBS.
    Symptoms such as back pain or lower extremity paresthesias typically begin 1–2 weeks after the infection, followed by symmetric weakness that begins in the feet and gradually ascends over hours to days. Weakness severity can range from mild to complete quadriplegia with respiratory failure.
    Autonomic symptoms are prominent, and cardiac instability can be life-threatening. Despite sensory symptoms (paresthesias), the sensory examination is often normal.
    A unique variant, Miller-Fisher syndrome, produces symptoms of ophthalmoplegia, ataxia, and areflexia, with little weakness of the extremities.
    Overall, GBS is a monophasic disease, with maximal symptoms seen by four weeks.
    Cardinal features on exam are areflexia and symmetric progressive weakness.
    CSF shows “albuminocytologic dissociationâ€Ââ€â€isolated elevated protein with normal WBC counts.
    Miller-Fisher syndrome is associated with anti-GQ1b antibodies.
    NCS reveals demyelinating changes of the proximal peripheral nerves.
    Serial PFTs with maximum inspiratory force and FVC are important for following diaphragmatic function, which often portends ventilatory failure.
    TREATMENT
    Standard treatment is either IVIG or plasmapheresis; steroids are not beneficial.
    Indications for plasmaphresis:
    Severe flaccid paralysis, bulbar palsy, progressive repiratory failureand patients on mechanical ventilation.
    It is most effective when it is started within seven days of the onset of symptoms.
    Plasmaphresis is not usually indicated for ambulatory patients with mild or non progressive disease.
    Daily administration of IVIG for two weeks may also be used to treat patients with GBS because it has shown to be effective as plasmaphresis.
    Mechanical ventilation should be considered when FVC falls to 15 mL/kg. Do not wait for PCO2 to rise. Keep patients with autonomic symptoms on cardiac telemetry.
    In Guillain-Barré syndrome, rapid progression to respiratory failure can occur within hours. Therefore, a timely and accurate diagnosis is critical.
    If you suspect Guillain-Barré syndrome, immediately admit the patient to the hospital regardless of the severity of the illness. Measurements of bedside vital capacity provide the most useful information regarding the degree of respiratory impairment. Patients with signs of respiratory failure should be promptly itubated and supported with mechanicial ventilation until the resolution of respratory muscle weakness.
    Signs of recovery within 1 to 3 weeks after onset favors a good prognosis. If illness continues for a longer period (e.g., beyond 6 weeks), a chronic relapsing course is more likely and prognosis is less favorable.
    It may take months before the patient recovers. A minority of patients experience recurrent attacks, and about 5% die due to respiratory failure, pneumonia, or arrhythmias.

    TICK BORN PARALYSIS:
    Most cases occur in North America and Australia..
    Tickïƒ Dermacentor andersoni (Rocky mountain wood tick) and D. variabilis (american dog tick).
    Sysmptomes develops 5 – 6 days after female tick attaches to the patient.
    The typical presentation is a progressive ascending paralysis that occur over matter of hours to days. Complete paralysis may develop in severe cases. Fever typicaly not present.
    Pupilary abnormalities are uncommon in tick born paralysis.
    If the patient has history of fever or prodormal illness the diagnosis in unlikely.
    Finding the attached tick on the skin is most important diagnostic measure.
    DD: GBS – progressive ascending paralysis in matter of days to weeks.
    MG : ascending paralysis not typical for MG.
    Botulism: decending paralysis, cranial nerves are affected early in disease and pupil abnormalities are common.
    Rx: in most cases of tick paralysis, removal of ticks will cause a substantial improvement of the paresis within several hours.
    VASCULITIC NEUROPATHIES
    Acute axonal neuropathies are seen in a wide variety of systemic vasculitides (infectious and inflammatory) and connective tissue diseases. Vasculitic infarction of individual peripheral nerves occurs in an asynchronous and asymmetric fashion, producing a multifocal neuropathy involving both sensory and motor fibers; this random involvement of multiple individual peripheral nerves is called mononeuritis multiplex.
    Sx/Exam: Include severe pain, paresthesias, and weakness. Progression occurs over days to weeks.
    Dx: NCS reveals axonal injury to multiple unrelated peripheral nerves; nerve biopsy typically shows axonal injury and inflammatory cell involvement of the nerve’s vascular supply.
    Tx: Requires aggressive treatment with both steroids and an immunomodulator such as cyclophosphamide or methotrexate.
    OTHER ETIOLOGIES
    Additional etiologies of acute-onset, rapidly progressive polyneuropathies include brachial neuritis, acute intermittent porphyria, toxin exposure (arsenic, lead), and infections (diphtheria, Lyme disease, HCV).

    Chronic Polyneuropathies
    CHARCOT-MARIE-TOOTH DISEASE
    The classic inherited polyneuropathy. Its prevalence is 1 in 2500, making it the most common inherited neurologic disorder. The family history is strongly +, with most forms being autosomal dominant.
    Sx/Exam: Symptoms begin in the first and second decades, usually with distal weakness in the legs. Patients have high-arched feet (pes cavus) and hammer toes; progressive atrophy and weakness of the hands and feet; distal sensory loss; and reduced or absent reflexes. Life expectancy is typically
    normal, but significant morbidity results from progressive weakness.
    Tx: No treatment is currently available.


    DIABETIC NEUROPATHY
    Diabetes is the most common cause of peripheral neuropathy in the United States, typically presenting as a slow-onset, distal, symmetric axonal polyneuropathy. Approximately 8–10% of all patients with diabetes develop neuropathy, usually associated with onset of diabetic retinopathy and
    nephropathy.
    Sx/Exam: This “length-dependent†neuropathy affects the longest nerves first, initially producing paresthesias and pain in the feet; progression leads to a stocking-glove distribution of sensory and motor deficits. Sensory, motor, and autonomic nerves can be affected, with sensory symptoms predominating.
    Tx: Prevention of onset or progression depends on tight glycemic control.
    Neuropathic pain symptoms (burning, pain) can be treated with TCAs such as amitriptyline, SSRIs such as duloxetine, and anticonvulsants such as gabapentin or carbamazepine.

    METABOLIC/INFECTIOUS NEUROPATHIES
    Many insidious and chronic polyneuropathies are metabolic in nature, with common causes being nutritional deficiencies (e.g., vitamin B12), toxin exposure (e.g., alcohol), and drug exposure (e.g., vincristine, INH, dapsone). In addition, many infections cause indolent polyneuropathies, including HIV
    and HSV; leprosy (Hansen’s disease, caused by Mycobacterium leprae) remains one of the most common causes of polyneuropathy worldwide.

    BRACHIAL PLEXUS DISORDERS
    Usually unilateral sensorimotor derangement attributable to one or more cords of the brachial plexus. Most cases have no apparent cause. May be due to trauma, radiation, infection, electrical injury, compression, or infiltration.
    Subtypes are as follows:
    Whole plexus lesion: The entire arm is paralyzed, with sensory loss complete past a line drawn from the shoulder to the middle third of the upper arm.
    Upper brachial plexus paralysis: Loss of shoulder abduction and elbow flexion. The affected arm is held internally rotated at the shoulder with the elbow extended and the forearm pronated. Sensory loss occurs over a small area of the deltoid muscle.
    Lower brachial plexus paralysis: Paralysis and wasting of the small muscles of the hand and of the long finger flexors and extensors → “claw hand†deformity. Sensory loss is found on the ulnar border of the hand and the inner forearm. Horner’s syndrome is possible.
    Lateral cord lesion: Weakness of flexion and pronation of the forearm.
    Medial cord lesion: Combined median and ulnar nerve deficit. ↓ or absent hand sensation and finger flexor function are seen with atrophy of intrinsic hand muscles.
    Posterior cord lesion: Weakness of the deltoid muscle and extensors of the elbow, wrist, and fingers. Sensory loss is seen on the outer side of the arm.
    Brachial neuritis: Acute onset of excruciating and generally unilateral shoulder pain followed days later by weakness of shoulder and parascapular muscles. Numbness may also be seen.
    Electrophysiologic testing of the affected muscles.
    AP and axillary lateral shoulder radiography for concerns of related fracture.
    MRI may reveal infiltrative processes.
    TREATMENT
    Physical/occupational therapy. Bracing prevents contractures.
    Possible surgery with nerve grafting and muscle or tendon transfers.
    Corticosteroids for brachial neuritis.
    COMPLICATIONS
    Incomplete recovery. Chronic shoulder pain is possible in brachial neuritis.



    MONONEUROPATHIES
    CARPAL TUNNEL SYNDROME
    The most common mononeuropathy; caused by compression of the median nerve at the flexor retinaculum of the wrist. Risk factors include repetitive hand-finger activities such as typing.
    Sx: Classic symptoms include progressive wrist pain; awakening at night with hand numbness; and paresthesias and weakness of the thumb and index finger.
    O/E Findings include atrophy of the thenar eminence (the palmar muscle bulk at the base of the thumb), weakness of thumb opposition, and sensory abnormalities of the thumb and index finger.
    Two classic bedside tests for carpal tunnel are Phalen’s sign (hyperflexion of the wrists leading to ↑ paresthesias) and Tinel’s sign (tapping over the median nerve at the level of the wrist eliciting electrical radiating sensations along the thumb and index finger).
    Dx: NCS provides the best objective test for median nerve abnormalities at the wrist.
    Tx: Options include immobilization with wrist splints, NSAIDs, local steroid injections, and surgical release at the wrist.
    Nocturnal paresthesias in the median nerve distribution are classic for carpal tunnel syndrome.
    Patients with carpal tunnel syndrome often have ↑ symptoms at night that are relieved by shaking or wringing their hands.
    RADIAL NERVE PALSY
    Typically results from acute injury to the nerve in the spiral groove of the humerus, most commonly by fracture of the humerus or direct compression of the nerve (“Saturday night palsyâ€Â).
    The most prominent symptom is “wrist drop†due to paralysis of the wrist extensor muscles; weakness of elbow extension (triceps) is also common.
    Dx: NCS helps identify the exact location and extent of the injury.
    Tx: Treatment is mainly supportive. Wrist splints may help restore function temporarily.

    ULNAR NEUROPATHY
    An overuse injury commonly caused by repetitive elbow flexion leading to trauma or compression at the elbow, particularly near the medial epicondyle. Common in thin women.
    Presents with paresthesias involving the fourth and fifth fingers, with weakness of the muscles that spread the fingers apart (the interossei), leading to the appearance, in its most chronic form, of a “claw hand.â€Â
    Tx: Splinting the elbows at night is first-line treatment and is most helpful in conjunction with NSAIDs if there is pain. Surgical release or transposition of the nerve near the elbow is often tried but is not always beneficial.

    BELL’S PALSY
    An acute-onset, unilateral paralysis of CN VII (the facial nerve).
    The upper and lower halves of one-half of the face are affected, resulting in inability to fully close the eye or move the mouth on that side.
    Facial weakness from a central cause (e.g., a stroke) typically spares the upper half of the face, producing unilateral lower facial weakness.
    In most cases, the etiology remains unclear, although an infectious or postinfectious cause is considered likely. Ramsay Hunt syndrome, in which unilateral facial paralysis is associated with herpetic blisters in
    the external auditory canal, supports this hypothesis.
    Diagnosis is clinical, but consider Lyme disease in endemic areas as the treatment approach is different.
    Do not use steroids if Lyme is suspected!
    Consider EMG testing if paresis fails to resolve within 10 days.
    Tx: Usually none is required, as most cases resolve in 1 month
    Short course of steroid therapy (prednisone) and acyclovir, if necessary
    Patient should wear eye patch at night to prevent corneal abrasion (cornea is exposed due to weakness of orbicularis oculi muscle)
    Surgical decompression of CN 7 is indicated if the paralysis progresses or if tests indicate deterioration.
  8. Guest

    Guest Guest

    NEUROCUTANEOUS SYNDROMES

    Neurofibromatosis Type I (von Recklinghausen's Disease)
    Autosomal dominant disease characterized by café au lait spots, neurofibromas, and CNS tumors (gliomas, meningiomas), axillary or inguinal freckling, iris hamartomas (Lisch's nodules), bony lesions
    Cutaneous neurofibromasâ€â€may be disfiguring
    Complications include scoliosis, pheochromocytomas, optic nerve gliomas, renal artery stenosis, and erosive bone defects. Musculoskeletal manifestations include spinal deformity and congenital tibial dysplasia.
    Complications may require treatment. Surgically excise any symptomatic neurofibromas.
    Other features that may be present in neurofibromatosis patients (both types)
    Seizures
    Mental retardation, learning disabilities
    Short height
    Macrocephalic
    Neurofibromatosis Type II
    Autosomal dominant disease; less common than type I neurofibromatosis
    Clinical features include bilateral (sometimes unilateral) acoustic neuromas (classic finding), multiple meningiomas, café au lait spots, neurofibromas (much less common than type I), and cataracts.
    In patients with neurofibromatosis, prognosis depends on the type and number of tumors and their location. Most patients can function well.
    Tuberous Sclerosis
    Usually autosomal dominant
    Presents with cognitive impairment, epilepsy, and skin lesions (including facial angiofibromas, adenoma sebaceum)
    Retinal hamartomas, renal angiomyolipomas, and rhabdomyomas of the heart may also be present.
    Treat complications.
    Sturge-Weber Syndrome
    Acquired disease
    Key pathologic feature is the presence of capillary angiomatoses of the pia mater
    Classic feature is facial vascular nevi (port-wine stain)
    Epilepsy and mental retardation are usually present.
    Treatment of epilepsy is often the mainstay of treatment.
    Von Hippel-Lindau Disease
    Autosomal dominant
    Important features are cavernous hemangiomas of the brain or brainstem, renal angiomas, and cysts in multiple organs.
    Associated with renal cell carcinoma
    SPINAL CORD DISEASES
    Syringomyelia
    Central cavitation of the cervical cord due to abnormal collection of fluid within the spinal cord parenchyma
    Causes include cranial base malformation (patients with Arnold-Chiari malformation), intramedullary tumors, and traumatic necrosis of the cord.
    Clinical featuresâ€â€bilateral loss of pain and temperature sensation over the shoulders in a "capelike" distribution (lateral spinothalamic tract involvement), preservation of touch, thoracic scoliosis may occur, muscle atrophy of the hands may occur
    Diagnosed by MRI
    Treatment is surgicalâ€â€syringosubarachnoid shunt
    Brown-Séquard Syndrome
    Spinal cord hemisection (i.e., lesion involving either the right or the left half of the spinal cord), usually at the cervical levels (where spinal cord enlarges)
    Causes include trauma (e.g., stab wound) that causes hemisection of spinal cord, tumors, and abscesses (less common).
    Clinical features: contralateral loss of pain and temperature (spinothalamic tract), ipsilateral hemiparesis (corticospinal tract), and ipsilateral loss of position/vibration (dorsal columns)
    Transverse Myelitis
    This is a rare condition that specifically affects the tracts across the horizontal aspect of the spinal cord at a given level. The thoracic spine is the most commonly involved.
    The cause is usually unknown, but it can occur after viral infections. Progression is usually rapid.
    Clinical features include lower extremity weakness or plegia, back pain, sensory deficits below the level of the lesion, and sphincter disturbance (especially urinary retention).
    MRI with contrast is the imaging study of choice.
    High-dose steroid therapy is often used, but evidence supporting its use is equivocal.
    The prognosis is highly variable and unpredictable, ranging from full recovery to death.
    Horner's Syndrome
    Results from the interruption of cervical sympathetic nerves
    Can be preganglionic (central lesions) or postganglionic (distal to superior cervical ganglion); the former is more worrisome and requires more thorough evaluation
    Ipsilateral ptosisâ€â€mild drooping of lid (levator palpebrae still intact)
    Ipsilateral miosisâ€â€"pinpoint pupil"
    Ipsilateral anhidrosis (decreased sweating on forehead)â€â€may be difficult to detect
    Causes
    Idiopathic (most cases)
    Pancoast tumor (pulmonary neoplasm of the superior sulcus at lung apex)
    Internal carotid dissection
    Brainstem stroke
    Neck trauma (cervical spine injury)
    Poliomyelitis
    Poliovirus affects the anterior horn cells and motor neurons of spinal cord and brainstem. Causes lower motor neuron involvement.
    Characteristic features include asymmetric muscle weakness (legs more commonly involved); absent deep tendon reflexes; flaccid, atrophic muscles; and normal sensation.
    Bulbar involvement (of CN IX and CN X) in 10% to 15% of cases can lead to respiratory and cardiovascular impairment.
    No treatment is available, although poliomyelitis is entirely preventable by vaccination
  9. Guest

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    SEIZURES

    A seizure is a paroxysmal neurologic event caused by abnormal, synchronous discharges from populations of cortical neurons.
    Epilepsy is a condition in which patients have unprovoked recurrent seizures. The key step in diagnosis and treatment is to determine whether the initial seizure activity is generalized or focal in onset

    1° Generalized Seizures
    Selected subtypes are as follows:
    Tonic-clonic (grand mal):
    The most common generalized seizure type; typically seen in genetic epilepsy syndromes and in seizures arising from metabolic abnormalities (e.g., hyponatremia, alcohol withdrawal, medications, CNS infections).
    Begin with stiffening of the extremities (tonic phase), often associated with a guttural cry from contraction of the expiratory muscles, followed by rhythmic clonic jerking of the extremities.
    Associated urinary incontinence, tongue biting, and postictal confusion is typically found.
    Myoclonic:
    A myoclonic jerk is an abrupt, brief, single contraction of a muscle group that produces a quick contraction and movement. Myoclonic seizures are characterized by frequent but asynchronous, nonrhythmic multifocal myoclonic jerks. Myoclonic jerks are most commonly seen with metabolic derangements (especially uremia) and are usually not epileptic.
    An important genetic cause of myoclonic seizures is juvenile myoclonic epilepsy; patients often have “staring spells†during childhood (brief alterations in consciousness often associated with eye blinking or
    chewing movements) and subsequently develop both myoclonic and tonic-clonic seizures in adolescence. They also experience myoclonic jerks when entering into or emerging from sleep.
    Atonic: The epilepsy type that can most resemble syncope clinically. Characterized by the abrupt loss of all muscle tone associated with a brief loss of consciousness. Primarily seen with inherited forms of childhood epilepsy.
    Lennox-Gastault syndrome is characterized by seizures of multiple types, impaired cognitive function and slow spike and wave activity on EEG. It usually presents in childhood.
    DIAGNOSIS
    If the patient has a known seizure disorder (epileptic), check anticonvulsant levelsâ€â€this is usually the only test that is needed. Because therapeutic anticonvulsant levels are variable, one dose may be toxic for one patient and therapeutic for another. Therefore, take the range given in laboratory reports as a general guideline.
    If the patient history is unclear or if this is the patient's first seizure:
    CBC, electrolytes, blood glucose, LFTs, renal function tests, serum calcium, urinalysis
    EEG: Although the EEG is the most helpful diagnostic test in the diagnosis of a seizure disorder, an abnormal EEG pattern alone is not adequate for the diagnosis of seizures.
    A normal EEG in a patient with a first seizure is associated with a lower risk of recurrence.
    CT scan of the headâ€â€to identify a structural lesion
    MRI of the brainâ€â€with and without gadolinium (first without)
    An important part of the workup of a patient with a first seizure
    More sensitive than a CT scan in identifying structural changes, but not always practical (e.g., in an unstable patient)
    LP and blood culturesâ€â€if patient is febrile
    Laboratory values to check immediately in an unfamiliar, seizing patient
    Serum calcium, Serum sodium , Serum glucose or Accu-Chek , BUN
    TREATMENT
    For all seizures, ABCs take priority: secure airway and roll patient onto his side to prevent aspiration.
    Patients with a history of seizures (epilepsy)
    Seizures in these patients are usually due to noncompliance with anticonvulsant therapy. (Even one missed dose can result in subtherapeutic levels). Give a loading dose of the anticonvulsant medication, and continue the regular regimen as before.
    These patients should be chronically managed by a neurologist. Treatment with one of the standard antiepileptic drugs provides adequate control in 70% of adult patients. In another 15% to 20%, a combination regimen controls seizures.
    If seizures persist, increase the dosage of the first anticonvulsant until signs of toxicity appear. Add a second drug if the seizures cannot be controlled with the drug of first choice.
    If the seizures are controlled, have the patient continue the medication for at least 2 years. If the patient remains seizure-free, taper the medication(s) cautiously. Confirm this decision with a lack of seizure activity on the EEG.
    Patient with a first seizure
    EEG and neurology consultâ€â€first steps
    Anticonvulsant therapyâ€â€weigh risks and benefits of treatment and the risk of recurrence before initiating
    With a normal EEG, the risk of recurrence is relatively low (15% in the first year), compared to the risk with an abnormal EEG (41% in the first year).
    Anticonvulsant agents
    For generalized tonic-clonic seizures and partial seizures
    Phenytoin and carbamazepine are the drugs of choice. They are equally effective, and side-effect profiles are similar.
    Other options include phenobarbital, valproate, and primidone.
    For petit mal (absence) seizuresâ€â€ethosuximide and valproic acid
    COMPLICATIONS
    Anticonvulsants and OCPs: Drugs that induce the liver cytochrome P-450 system (e.g., phenytoin and carbamazepine) can lead to ↓ effective levels of other medications, including OCPs. All female patients taking such anticonvulsants should be counseled to consider other means of birth control or use OCPs with high levels of estrogen.
    Anticonvulsants and birth defects: Use of anticonvulsants during pregnancy is associated with an ↑ risk of birth defects, particularly neural tube defects. All women of childbearing age who use anticonvulsants should be advised to take at least 0.4 mg/day of folate. Pregnant women with epilepsy
    should be treated with a single anticonvulsant at the lowest therapeutic dose; valproic acid is particularly teratogenic.
    Elderly patients may be particularly sensitive to the cognitive, motor, and coordination side effects of phenytoin, even if the serum phenytoin level is in the therapeutic range. Gabapentin, lamotrigine, and carbamazepine are equally effective at controlling partial onset seizures in the elderly, but gabapentin and lamotrigine are better tolerated
    Phenytoin toxicity:
    It is important to recognize the early signs and symptoms of phenytoin toxicity. The earliest sign is the presence of nystagmus of fal lateral gaze. Some other facts include blurred vision, diplopica, ataxia, slurred speech, dizziness, drowsiness, lethargy and decreased mentation, which progress to coma. Systemic side effects and neurotoxicity is one of the major limitations to the use of phenytoin.
    Usuall therapeutic range of phenytoin is between 10 – 20 mcg/mL and most patients will experience adverse dose related neurotoxic effects with levels greater than 20 mcg/mL. however the serum levels associated with neurotoxixty vary from patient to patient. Some patients can experience toxic effects even when the measured levels are well within the normal range.
    The first step in the management of the side effects due to higher drug levels is t reduce the dose or alter the treatment schedule to minimize the peak drug levels.

    Focal (Partial) Seizures
    Much more common than 1° generalized seizures, focal seizures originate from a small, discrete focal lesion within the brain that gives rise to abnormal synchronized neuronal discharges. This activity may then spread to involve other areas of the brain. Subtypes are as follows:
    Simple partial seizures:
    Focal seizures in which no alteration of consciousness is noted.
    Initial symptoms depend on the location of the seizure focus and commonly include twitching/jerking of one side of the body (focal motor seizures) or sensations of strange smells or sounds.
    Complex partial seizures:
    Evolve from simple partial seizures as the initial focal seizure activity spreads to involve some but not all of both cerebral hemispheres. In fact, the stereotypical warning or aura that many patients report is simply the manifestation of the initial simple partial seizure.
    As seizure activity spreads, patients develop an impairment of consciousness and behavioral arrest during which they display stereotypical behaviors known as automatisms (e.g., lip smacking, chewing,
    pulling at clothes).
    In contrast to simple partial seizures, complex partial seizures are associated with postictal confusion and lethargy.
    Complex partial seizures with 2° generalization:
    In many patients with prolonged complex partial seizures, seizure activity can ultimately spread to involve the entire cerebral cortex. The manifestation of the “2° generalization†of the initial focal seizure activity is usually generalized tonic-clonic activity.
    Generalized seizures can thus be either 1° (generalized seizure activity at onset) or 2° (initial focal activity that spreads to involve the entire cortex).
    Todd’s paralysis:
    Patients with focal-onset seizures often have transient (minutes to hours) focal weakness or paralysis following seizure termination. This weakness usually involves the area of the body first affected by the
    seizure, providing an important clue to the focus of seizure onset.
    A patient with a generalized tonic-clonic seizure who is subsequently noted to have a postictal left hemiparesis likely had a focal-onset seizure that began in the right hemisphere and secondarily generalized.
    Temporal lobe epilepsy: The most common cause of simple and complex partial seizures is temporal lobe pathology, most commonly 2° to abnormalities of the hippocampus. Hippocampal sclerosis/calcification is seen on imaging. The classic auras of odd smells, sounds, or tastes are associated
    with temporal lobe epilepsy.
    DIAGNOSIS
    Given that focal (partial) seizures arise from focal lesions, brain imaging studies are typically abnormal; EEG often shows localized (i.e., asymmetric) epileptiform activity. HSV encephalitis must be ruled out via CSF studies in patients with new-onset temporal lobe seizures.
    TREATMENT
    Medications: Focal-onset seizures are best treated with anticonvulsants such as phenytoin, carbamazepine, phenobarbital, and valproic acid. Newer medications such as gabapentin, levetiracetam, lamotrigine, and topiramate are also useful.
    Vagal nerve stimulators: Although their mechanism of action remains unclear, vagal nerve stimulators can ↓ the frequency of focal-onset seizures by 25% in patients with medically refractory seizures. A pacemaker-like device is implanted in the chest with leads attached to one of the vagal
    nerves
    Surgery: Patients with focal-onset seizures often have an identifiable brain lesion on imaging studies. This is particularly true of temporal lobe epilepsy 2° to hippocampal lesions. In such patients with medically refractory seizures, surgical resection of the causative lesion (e.g., temporal lobectomy) can produce striking results, with up to 50–75% of patients becoming seizure free.
    Patients with epilepsy who fail to respond to three trials of antiepileptic drugs are unlikely to ever become seizure free with drug therapy. Treatment-resistant patients with epilepsy should be evaluated for a surgically remediable epilepsy syndrome.
    Nonepileptic seizures of psychogenic origin can be differentiated from epilepsy by their longer duration, normal electroencephalogram findings, and maintenance of consciousness.
    Nonepileptic psychogenic seizures are often associated with moaning, crying, and arrhythmic shaking of the body.

    Status Epilepticus
    Traditionally defined as (1) continuous seizure activity lasting > 30 minutes, or (2) recurrent seizures without return of normal consciousness between seizures. Practically speaking, seizure activity lasting > 5 minutes is unlikely to remit spontaneously and carries the risk of permanent neuronal injury. Generally,
    ongoing or recurrent seizure activity lasting > 5 minutes is thus considered a medical emergency and treated as status epilepticus.
    TREATMENT
    Treatment guidelines are as follows:
    ABCs.
    Labs: Draw labs for metabolic abnormalities (e.g., glucose, sodium, calcium).
    Pharmacologic:
    Administer thiamine and glucose.
    Benzodiazepines are first-line anticonvulsants for status epilepticus. Give lorazepam 0.1 mg/kg IV at 1–2 mg/min.
    Fosphenytoin (20 mg/kg “phenytoin equivalents†IV at 150 mg/min) should then be started immediately even if seizures terminate with lorazepam.
    If seizures persist, the next step is to give a second load of phenytoin or fosphenytoin using an additional 5–10 mg/kg IV load or move directly to the next step.
    If seizures continue, the next step is to administer pentobarbital, midazolam, or propofol. Use of any of these medications typically requires continuous EEG recordings, mechanical ventilation, and cardiac pressors.
    Infantile Spasms (West Syndrome)
    Affects males more often than females; the initial event occurs between 3 and 12 months of age. Associated with a + family history.
    Hx/PE: Tonic, bilateral, symmetric head jerks that tend to occur in clusters of 5–10; arrest of psychomotor development at the age of seizure onset. The majority of patients have mental retardation.
    Dx: Abnormal interictal EEG (very high amplitude slow waves).
    Rx: Hormonal therapy with ACTH, prednisone, and clonazepam or valproic acid.
  10. Guest

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    CEREBROVASCULAR DISEASE

    The differential of an acuteonset focal neurologic deficit includes stroke, seizure, and complicated migraine.
    A stroke is characterized by acute-onset focal neurologic deficits due to disruption of blood flow (by either occlusion or rupture) to a given area of the brain. By traditional definition, the neurologic deficits last > 24 hours. The residual deficit is related to underlying infarction of the brain.
    A transient ischemic attack (TIA) is fundamentally similar to stroke, but by traditional definition the deficits resolve within 24 hours. (In the overwhelming majority of TIAs, the deficits actually resolve in < 1 hour.) In TIAs, a region of the brain is briefly ischemic, but flow is restored before
    permanent infarction occurs.
    Anterior circulation: Arise from the internal carotid artery (ICA) and include the ophthalmic artery, the anterior cerebral artery (ACA), and the middle cerebral artery (MCA).
    Posterior circulation:
    Arise from both vertebral arteries as they travel up along the upper cervical spinal cord and fuse to form the basilar artery. The basilar artery travels along the brain stem, ultimately dividing into the two posterior cerebral arteries (PCAs) that supply the occipital lobes.
    Three large pairs of arteries come off the vertebrobasilar system to supply the cerebellum: the anterior inferior cerebellar arteries (AICA), posterior inferior cerebellar arteries (PICA), and superior cerebellar arteries (SCA). Small perforating arterioles coming directly off the basilar artery provide vital supply to the brain stem.
    Ischemic Stroke
    Caused by occlusion of arterial blood flow to the brain, which in turn is caused by either extracranial embolism of clot to the large intracranial vessels or progressive thrombosis of small intracranial arterioles.
    EMBOLIC STROKE
    Occurs when an extracranial thrombus dislodges and embolizes to and occludes one of the large intracranial vessels (ophthalmic, ACA, MCA, PCA, vertebral, basilar, AICA, PICA, or SCA). Emboli most commonly arise from atherosclerotic plaques of the extracranial ICA (artery-to-artery emboli) or
    from the heart. Common sources include the following:
    Atrial fibrillation (AF), with clot arising in the left atrial appendage.
    Valvular disease (e.g., endocarditis, prosthetic valves) is also associated with cardiogenic emboli.
    Patients with severe left ventricular dysfunction and regional wall motion abnormalities following MI can form ventricular thrombi that embolize.
    Severe atheromatous disease of the proximal aortic arch can also generate cerebrovascular emboli.
    Paradoxical emboli can arise from right-to-left shunting of venous thrombi and emboli across an atrial septal defect.
    Key points to direct workup are as follows:
    An embolic stroke involving the posterior circulation (cerebellum, brain stem, occipital lobes) is not caused by ICA emboli.
    Amaurosis fugax (acute transient monocular vision loss) is most commonly caused by cholesterol emboli from an atherosclerotic plaque of the ipsilateral ICA.
    When a patient presents with painless visual loss lasting a few seconds(Amaurosis fugax)- If one looks in the eye, cholesterol particles (Hollenhorst bodies) will be seen. This event is a warning sign of an impending stroke), a duplex ultrasound of the carotids should be the first test of choice.
    Embolic strokes involving the anterior circulation (ACA or MCA) can be 2° to either internal carotid emboli or cardiogenic emboli.
    Imaging studies are as follows:
    Brain: A head CT is the initial study of choice for acute stroke, primarily to evaluate for intracranial hemorrhage. MRI is best for characterizing the location and size of ischemic strokes.
    Internal carotid: Use Doppler ultrasound, CTA, or MRA of the extracranial carotid arteries to evaluate for significant stenosis (> 70%).
    Heart: Transesophageal echocardiography (TEE) is superior to transthoracic echocardiography (TTE) for evaluating potential cardiac sources of emboli. Echocardiography is indicated in patients with suspected embolic stroke abd in patients in whom the mechanism of stroke is not clear, especially if crotid studies are negative.
    Other important studies include the following:
    ECG: The initial screening test for cardiac arrhythmias, especially AF or flutter.
    Cardiac telemetry: Monitoring patients on continuous cardiac telemetry for 24–48 hours can help detect paroxysmal AF.
    Patients < 50 years of age with unexplained embolic stroke should be evaluated for underlying hypercoagulable states (e.g., antiphospholipid syndrome, antithrombin III, protein S and C deficiency, factor V Leiden mutation).
    TREATMENT
    Specific treatments to ↓ the risk of recurrent embolic strokes are as follows:
    Symptomatic internal carotid stenosis: Patients with embolic stroke involving the anterior circulation who are found to have > 70% stenosis of the ipsilateral ICA benefit from carotid endarterectomy. Carotid stenting is another less proven alternative.
    Prevention of strokes due to embolic diseaseâ€â€anticoagulation (aspirin), reduction of atherosclerotic risk factors
    Symptomatic patients: Three major studies have established the benefit of carotid endarterectomy in symptomatic patients with carotid artery stenosis of >70%. Patients with stenosis < 30 % -- medical therapy. And patients between 30 and 70 %-- treatment is controversial.
    Asymptomatic patients: Four major studies have investigated the benefit of carotid endarterectomy in asymptomatic patients. Three found no benefit. One study (ACAS) found that in asymptomatic patients who have a carotid artery stenosis of >60%, the benefits of surgery are very small. Therefore, in asymptomatic patients, reduction of atherosclerotic risk factors and use of aspirin are recommended.
    If patient is on aspirin already, add diperydamol. If still he experiences TIAs – surgery in < 70 % stenosis is indicate.
    Aspirin is indicated for the secondary prevention of stroke (in patients who had a previous CV events) and for the primary prevention of stroke in diabetic patients. This drug along with warfarin is CI in patients with PUD. Patients at high risk of GI bleeding and those with aspirin intolerance can be treated with clopidogrel. Ticlodipine is associated with significant neutropenia and thrombocytopenia.
    Atrial fibrillation: Warfarin therapy with a goal INR of 2–3 is the optimal treatment for patients with paroxysmal or chronic AF. Drug interactions and concurrent medical problems are among the most common cause of suboptimal or excessive anticoagulation in patients on wrfarin therapy.
    Excessive anticoagulation (INR> 4) increases the risk of bleeding complications substantially, therefore careful monitoring of coagulation profile is crucial.
    Cardiogenic emboli: In practice, specific identifiable cardiac sources (e.g., left ventricular thrombus) are typically treated with warfarin for 4–6 months.
    Cryptogenic embolic stroke: In embolic stroke patients for whom no clear source is identified, antiplatelet medications are the treatment of choice to prevent recurrent strokes.
    THROMBOTIC STROKE
    Occurs when a small cerebral artery gradually occludes 2° to progressive local thrombosis. The classic vessels involved are the small penetrating terminal arterioles that supply the brain stem and the deep structures of the cerebral hemispheres, including the basal ganglia, thalami, and internal capsule.
    The internal capsule is of particular importance in that it contains the descending motor fibers from the motor cortex as they travel toward the brain stem and spinal cord. Occlusion of these small arterioles produces a discrete “lacunar†infarct of the small area of brain supplied by the terminal
    arteriole.
    Lacunar infarcts typically occur in vital structures (e.g., brain stem, internal capsule) and, despite their small size, can have devastating effects. The four classic “lacunar†strokes are as follows:
    Pure motor hemiparesis: Presents with isolated weakness of the face, arm, and leg on one side of the body. Sensation is normal, and no “cortical signs†(e.g., aphasia, visual field deficits) are present.
    Dysarthria–clumsy hand syndrome: Essentially a variant of pure motor hemiparesis, with isolated slurred speech and unilateral hand weakness and incoordination.
    Ataxia hemiparesis: Patients have mild weakness of the face, arm, and leg on one side associated with marked ataxia of the same side of the body.
    Pure sensory loss: Patients have complete loss of sensation on one side of the body.
    Other lacunar strokes: The “named†brain stem strokes (e.g., Wallenberg’s) are typically caused by a small vessel lacunar stroke from thrombosis.
    Thalamic stroke (Dejerineâ€ÂRoussy syndrome): It is caused by a stroke involving ventral posteroâ€Âlateral (VPL) nucleus of the thalamus that transmits sensory information from the contralateral side of the body.
    The stroke results in contralateral hemianesthesia that can be accompanied by transient hemiparesis, athetosis, or ballistic movements. Dysesthesia of the area affected by the sensory loss is characteristic and is called ‘thalamic pain’ phenomenon.
    Imaging studies, particularly with MRI, are key in demonstrating strokes caused by small vessel thrombosis. This can limit the necessary workup (e.g., there is no need to pursue aggressive diagnostic tests for an embolic source) and focus treatment (e.g., warfarin therapy is not appropriate treatment for
    small vessel thrombotic strokes).
    Vertebral artery dissection typically presents with neck or head pain, Horner's syndrome, dysarthria, dysphagia, decreased pain and temperature sensation, dysmetria, ataxia, and vertigo.
    Magnetic resonance angiography is a sensitive diagnostic test for vertebral artery dissection as a cause of stroke.
    TREATMENT
    The 1° risk factors for small vessel thrombotic strokes are hypertension (most important), diabetes, hyperlipidemia, and smoking. Prevention of small vessel thrombotic ischemic strokes rests primarily on aggressive control of these risk factors.
    Acuteâ€â€Supportive treatment (airway protection, oxygen, IV fluids) is initiated. Early recognition of the cause of stroke is unreliable, and early treatment is critical. Therefore, choose therapies that have broad efficacy and safety.
    o Thrombolytic therapy (t-PA) If administered within 3 hours of the onset of an acute ischemic stroke, improved clinical outcome is seen at 3 months.
    Do not give t-PA if the time of stroke is unknown, if more than 3 hours have passed, or if the patient has any of the following: uncontrolled HTN, bleeding disorder or is anticoagulated, or a history of recent trauma or surgery. These patients are at increased risk for hemorrhagic transformation.
    If t-PA is given, there is risk of intracranial hemorrhage. Therefore, do not give aspirin for the first 24 hours, perform frequent neurologic checks (every hour), and carefully monitor BP. (Keep BP 220, diastolic >120, or mean arterial pressure >130 mm Hg).
    o The patient has a significant medical indication for antihypertensive therapy.
    Examples include: Acute MI, Aortic dissection, Severe heart failure, Hypertensive encephalopathy
    o The patient is receiving thrombolytic therapyâ€â€Aggressive blood pressure control is necessary to reduce the likelihood of bleeding.
    Despite the initial encouraging evidence, large- scale studies demonstrated no improvement in the outcome of patients with thrombotic stroke receiving nimodipine.
    Spasticity is an important problem of many post stroke-patients. Although spasticity may have several advantages (maintains muscle bulk, decrease the incidence of DVT, and may be used as platform for lower extremity bearing), it limits or prevents muscle from proper functioning, cause pain, and leads to joint contractures. Post stroke patients with significant spasticity should be treated with dantrolene.
    Preventionâ€â€Specific recommendations for the prevention of strokes depend on the underlying etiology of the stroke.
    Prevention of strokes due to atherosclerosis of the carotid arteries:
    Control of risk factorsâ€â€HTN, DM, smoking, hypercholesterolemia, obesity, Aspirin
    For explaination – see above
    o Prevention of lacunar strokesâ€â€control of hypertension
    If a patient presents to the ED with findings suggestive of an acute stroke, order the following: Noncontrast CT scan of the brain ECG, chest radiograph CBC, platelet count PT, PTT Serum electrolytes Glucose level Bilateral carotid ultrasound Echocardiogram
    If stroke is caused by emboli from a cardiac source, anticoagulation is the treatment.
    Treatment of strokes is prophylactic. Once a stroke has occurred, there is nothing that can be done to salvage the dead brain tissue. The goal is to prevent ischemic events in the future.
    Antiplatelet therapy reduces the risk of recurrent strokes in this patient population; choices include aspirin, clopidogrel, and ASA/dipyridamole.
    Infection with fever can temporarily exacerbate a chronic neurologic defect in a patient with a previous stroke
    Hemorrhagic Stroke
    Caused by rupture of blood vessels within the brain parenchyma. As with ischemic stroke, focal symptoms depend on the location of the hemorrhage.
    In contrast to ischemic stroke, intraparenchymal hemorrhages are usually associated with headache and rapid deterioration in level of consciousness.
    The leading cause of hemorrhagic strokes is hypertension. Hypertensive hemorrhages classically occur in four subcortical structures: the basal ganglia, thalamus, cerebellum, and pons (part of the brain stem).
    Intraparenchymal hemorrhages occurring within the cortical white matter (so-called lobar hemorrhages) can be caused by hypertension but raise suspicion for other etiologies, such as metastatic lesions, vascular abnormalities (e.g., AVMs), hemorrhagic conversion of an ischemic stroke, infections (especially septic emboli), and cerebral amyloid angiopathy.
    TREATMENT
    Admission to the ICU
    ABCs (airway, breathing, and circulation)â€â€Airway management is important due to altered mental status and respiratory drives. Patients often require intubation.
    BP reduction: Elevated BP increases ICP and can cause further bleeding. However, hypotension can lower cerebral blood flow, worsening the neurologic deficits. Therefore, BP reduction must be gradual so as to not induce hypotension.
    Treatment is indicated if systolic BP is >160 to 180 or diastolic BP is >105. Treatment for BP lower than these values is controversial.
    Nitroprusside is often the agent of choice.
    Mannitol (osmotic agent) and diuretics can be given to reduce ICP. Use these agents only if ICP is elevated; do not give them prophylactically.
    Use of steroids is harmful and is not recommended.
    Rapid surgical evacuation of cerebellar hematomas can be life-saving. However, surgery is not helpful in most cases of intracerebral hemorrhage.
    Two major categories of hemorrhagic stroke
    Intracerebral hemorrhage (ICH)â€â€bleeding into brain parenchyma
    Subarachnoid hemorrhage (SAH)â€â€bleeding into the CSF; outside brain parenchyma
    Cocaine is one of the main causes of stroke in young patients. ICH, ischemic stroke, and SAH are all associated with cocaine use. Pupillary findings in ICH and corresponding level of involvement
    Pinpoint pupilsâ€â€pons
    Poorly reactive pupilsâ€â€thalamus
    Dilated pupilsâ€â€putamen
    It is often difficult to distinguish ischemic stroke from an ICH on clinical grounds. The emergent treatment is initially the same until the diagnosis is certain. CT scan is the test that identifies ICH in the initial period.

    A carotid bruit has two causes.
    Murmur referred from the heart
    Turbulence in the internal carotid artery (serious stroke risk)
    Subclavian Steal Syndrome
    Caused by stenosis of subclavian artery proximal to origin of vertebral arteryâ€â€exercise of left arm causes reversal of blood flow down the ipsilateral vertebral artery to fill the subclavian artery distal to the stenosis because it cannot supply adequate blood to left arm
    Leads to decreased cerebral blood flow (blood "stolen" from basilar system)
    Causes symptoms of vertebral basilar arterial insufficiency (see Box 5-1)
    BP in left arm is less than in right arm; decrease in pulse in left arm
    Upper extremity claudication
    Treatment: surgical bypass

    TIAs Can Involve Either the Carotid or the Vertebrobasilar System
    Carotid System
    Temporary loss of speech; paralysis or paresthesias of contralateral extremity; clumsiness of one limb
    Amaurosis fugax (an example of a TIA): transient, curtain-like loss of sight in ipsilateral eye due to microemboli to the retina
    Vertebrobasilar System (i.e., Vertebrobasilar TIAs)
    Decreased perfusion of the posterior fossa
    Dizziness, double vision, vertigo, numbness of ipsilateral face and contralateral limbs, dysarthria, hoarseness, dysphagia, projectile vomiting, headaches, and drop attacks
    Prognosis: several studies suggest that early initiation of rehabilitation therapy (physical, occupational, and speech therapy) after stroke can improve recovery process and functional status. In 30 days stroke survivors 10 % demonstrate complete recovery, 10 % don’t respond any therapy and 80 % may potentially benefit form a complex rehabilitation process. Stroke survivors who don’t go go rehabilitation are more likely to be institutionalized.

    Superior sggital sinus thrombosis:
    Rare condition associated with rauma, infection, hypercoagulation, vasculitis, nephritic syndrome, severe dehydration and pregnancy.
    Diagnosis is suggested by history (headache, associated conditions), physical findings (hemiparesis, papilledema, seizure) and imaging tests. MRI imaging and MR venography are very useful in establishing the diagnosis.
    The management of patients typically includes adequate anticoagulation with heparin, even if an area of hemorrhagic infarction is demonstrated on CT. It is important to understand that the hemorrhagic foci that occur in this case are secondary to venous hypertension.
  11. Guest

    Guest Guest

    EPIDURAL HEMATOMAS

    Typically caused by trauma to the side of the head, usually near the ear, resulting in injury to the middle meningeal artery (MMA). The MMA runs between the skull and the dura, and injury thus produces bleeding into the epidural space. Such hematomas can expand rapidly, as they are produced by arterial bleeding.
    Sx/Exam: Although seen in < 25% of patients, the classic presentation is that of head trauma with brief (seconds to minutes) loss of consciousness followed by a “lucid period†in which mental status and level of alertness are normal for minutes to hours. Followed by a rapid decline in mental status.
    Dx: Since the dura is tacked down to the skull at the suture lines, epidural bleeds will tamponade in a confined space and will not cross the sutures, leading to the characteristic “lens-shaped†hematoma on CT scan.
    Tx: Symptomatic epidural hematomas must be treated with urgent neurosurgical decompression.

    If a pt comes in with hemiplasia, you need to first ddx b/w Hemorrhagic and Ischemic stroke and then give medication. To DDX you need to do CT WITH OUT contrast, if its ischemic (thrombi) then we give aspirin and then we do carotid Doppler and TEE to evaluate source of embolism.


    SUBDURAL HEMATOMAS
    Typically caused by head trauma that leads to a rapid deceleration of the skull (e.g., car accident) and subsequent shearing of the cerebral bridging veins as they travel through the subdural space into the draining venous sinuses.
    Most often seen in elderly who have falls, and alcoholics. Spontaneous subdural hematomas may also occur, particularly in patients with underlying coagulopathy or thrombocytopenia.
    Sx/Exam: Can produce mass effect, which typically manifests as a progressive decline in mental status.
    Dx: Head CT reveals hematoma layering along the outer surface of the cerebral cortex. Must be in the differential of any elderly patient with dementia.
    Tx: Tx is centered on prevention of ICP by head elevation, hyperventilation (causes vasoconstriction and thus decreases cerebral blood flow), and if needed acetazolamide and mannitol. If there is a midline shift then Craniotomy is indicated but its asso with grave prognosis.

    SUBARACHNOID HEMORRHAGE (SAH)
    The most common cause of nontraumatic SAH is a ruptured intracranial aneurysm. They are most prone to rupture when they’re >7mm.
    AVM is the MCC of SAH in children, the hx of seizure and migrain like headache is characteristic.
    Sx/Exam: Patients experience abrupt-onset severe headache (“the worst headache of my life†or “thunderclap†headache) often associated with nausea and vomiting. There may also be a ↓ level of consciousness and focal neurologic deficits.
    Dx: Noncontrast CT scanâ€â€identifies the majority of SAHs. However, CT scan may be negative in up to 10% of cases.
    Perform lumbar puncture if the CT scan is unrevealing or negative and clinical suspicion is high. LP is diagnostic.
    Blood in the CSF is a hallmark of SAH. (Be certain that it is not traumatic blood.)
    Xanthochromia (yellow color of the CSF) is the gold standard for diagnosis of SAH. Xanthochromia results from RBC lysis. Xanthochromia implies that blood has been in CSF for several hours and that it is not due to a traumatic tap.
    Once SAH is diagnosed, order a cerebral angiogram. It is the definitive study for detecting the site of bleeding (for surgical clipping).
    Within the first 72 hours, up to10% of SAHs are not seen on CT, underscoring the importance of lumbar
    puncture following imaging if the diagnosis is suspected. After 72 hours, the rate of --ive CT scans ↑ substantially.
    Patients with a confirmed SAH should then have conventional cerebral angiography to determine the presence, location, and anatomy of the aneurysm.
    Tx: The first priority is to secure the aneurysm as soon as possible, as the risk of rebleeding is significant in the first 48 hours. Currently, aneurysms are treated with either neurosurgical clipping or endovascular coiling.
    Medicalâ€â€Therapy reduces the risks of rebleeding and cerebral vasospasm.
    Bed rest in a quiet, dark room
    Stool softeners to avoid straining (increases ICP and risk of repeated rerupture)
    Analgesia for headache (acetaminophen)
    IV fluids for hydration
    Control of HTNâ€â€Lower the BP gradually because the elevation in BP may be a compensation for the decrease in cerebral perfusion pressure (secondary to increased ICP or cerebral arterial narrowing).
    Calcium channel blocker (nifedipine) for vasospasmâ€â€lowers the incidence of cerebral infarction by one third
    Complications
    Reruptureâ€â€occurs in up to 30% of patients
    Vasospasmâ€â€occurs in up to 50% of patients (more often with aneurysmal SAH); can cause ischemia/infarction and therefore stroke
    Nimodipine reduces complications from vasospasm and is given to all patients with SAH. Vasospasm is also treated with “triple-H therapy†(hypertension, hypervolemia, and hemodilution) in an effort to augment blood flow in areas of vasospasm.
    Hydrocephalus (communicating)â€â€secondary to blood within the subarachnoid space hindering normal CSF flow
    Seizures may occur (blood acts as an irritant).
    SIADH: SAH or "cerebral-salt wasting syndrome". Patholgy involves 1-SIADH (inappropriate vasopressin secretion) which causes water retention. 2-an increased secretion of an atrial/brain natriuretic peptide. SIADH also results in hyponatremia for which water restriction is the tx of choice. So Hyponatremia is one of the important complications of SAH. This usually clears within 1-2 weeks.
    Common sites of SAH
    Junction of anterior communicating artery with anterior cerebral artery
    Junction of posterior communicating artery with the internal carotid artery
    Bifurcation of the MCA
    Polycystic kidney disease is associated with berry aneurysms. Caution: Ophthalmologic examination is mandatory to rule out papilledema. If papilledema is present, do not perform a lumbar puncture you may cause a herniation. Repeat the CT scan first.
  12. Guest

    Guest Guest

    GIT

    Achalasia

    Due to idiopathic dysfunction of distal esophageal neural structures leading to impaired relaxation of distal esophageal sphincter (LES) during swallowing
    20-40 years old; incidence ↑ with age. males=females
    Indistinguishable from esophageal dysmotility caused by Chagas’ disease.
    Dysphagia for both solids and liquids
    Weight loss
    Nocturnal cough, recurrent aspiration, bronchitis, pneumonia
    Patients with achalasia often lift their arms over their heads or extend their necks to aid in swallowing.
    X-ray (not needed)  air-fluid level in the distal esophagus
    Initial test  barium swallow showing dilated esophagus which tapers as a “bird’s beak” at the LES
    Next step  esophagoscopy with biopsies to rule out secondary causes of achalasia (cancer, Chagas’ disease)
    Most accurate test  esophageal manometry showing:
    1. Increased LES pressure
    2. Impaired relaxation of LES with swallowing
    3. Absence of normal peristaltic activity throughout the esophagus
    Initial therapeutic measure  pneumatic dilation
    If ineffectvie or patient refusal to undergo pneumatic dilation  botulinum toxin injection (everyone needs re-injection after some time)
    Injected into the LES. Performed endoscopically and associated with an 85% initial response, but > 50% of patients require repeated injection within six months. Ideal if the patient is a poor
    candidate for more invasive treatment.
    If both ineffective then proceed to Heller myotomy (usually done laparoscopically with a risk of post-op reflux development)
    Diffuse Esophageal Spasm
    Intermittent chest pain relieved by nitroglycerin thus simulating myocardial infarction but unrelated to exertion or eating (ruling out myocardial infarction and odynophagia, respectively)
    Diffuse esophageal spasm is marked by uncoordinated contractions, whereas nutcracker esophagus is characterized by excessively high-amplitude contractions.
    Both show a female predominance; onset is usually after age 40.
    Pain may be precipitated by drinking extremely cold or hot liquids
    Dysphagia, especially for liquids
    Unlike achalasia, diffuse esophageal spasm and nutcracker esophagus often present with chest pain rather than with dysphagia.
    If can not differentiate clinically between Esophageal Spasm and MI proceed to EKG
    Initial test  barium swallow showing a “corkscrew” appearance
    Most accurate test  esophageal manometry showing:
    1. high amplitude, repetitive, simultaneous contractions
    2. nutcracker esophagus  high amplitude, prolonged contractions
    Management  Ca+ channel blockers (nifedipine, etc.) or nitrates
    If severe and resistant to all forms of therapy proceed to longitudinal esophageal myotomy
    Scleroderma
    Esophageal involvement due to atrophy and fibrosis of the esophageal smooth muscle (distal 2/3 of esophagus)
    Other manifestations of scleroderma (distal skin thickening, Raynaud’s phenomenon, visceral involvement)
    Dysphagia for both solids and liquids (not a constant feature in test questions)
    Severe heartburn (strictures develop in long-term survivors and patients report improvement of symptoms of reflux, but increased dysphagia; diagnosis made by endoscopy with biopsies;treated with tapered bougies or balloon dilatation)
    LES neither contracts nor relaxes, hence the presence of both dysphagia and heartburn
    Initial test (also the most accurate)  esophageal manometry showing:
    1. decreased LES pressure
    2. low amplitude, weak peristaltic contractions in the distal 2/3 of the esophagus
    Management  same as GERD (mainly proton-pump inhibitos, such as lansoprazole)
  13. Guest

    Guest Guest

    Gastroesophageal reflux disease (GERD)

    Usually due to idiopathic dysfunction of the LES
    Secondary causes of decreased LES pressure include:
    1. pregnancy (due to smooth muscle relaxation from increased progesterone concentration)
    2. nicotine
    3. alcohol
    4. caffeine
    5. peppermint
    6. chocolate
    7. drugs (nitrates, ca+ channel blockers, anticholinergics, β-blockers)
    Risk factors  obesity, scleroderma, pregnancy, hiatal hernia
    Heartburn (substernal chest pain) after a heavy meal, when lying down, bending forward or wearing tight-clothing
    Sour-metallic taste in the mouth
    Regurgitation
    Recurrent laryngitis (hoarsness)
    Cough and wheezing (reflux-induced asthma)
    Stricture development (improved heartburn, but appearance of dysphagia for solids)
    Next step in management if the clinical picture is conclusive, proceed directly to a trial of proton-pump inhibitors (PPIs)
    If the patient is unresponsive to therapy or has alarm symptoms (dysphagia, odynophagia, weight loss, anemia, long-standing symptoms, blood in stool, age > 50), proceed as follows:
    Barium esophagography: Has a limited role, but can identify strictures.
    Upper endoscopy with biopsy: The standard exam in the presence of alarm symptoms (dysphagia, odynophagia, weight loss, bleeding, anemia).
    Normal in > 50% of patients with GERD (most have nonerosive reflux disease), or may reveal endoscopic esophagitis grades 1 (mild) to 4 (severe erosions, strictures, Barrett’s esophagus). Strictures can be dilated.
    If diagnosis in question or for evaluation of recurrent laryngitis, chronic cough (especially if nocturnal) or unexplained asthma perform 24 hour pH monitoring
    The gold standard, but often unnecessary. Indicated for correlating symptoms with pH parameters
    when endoscopy is normal and (1) symptoms are unresponsive to medical therapy, (2) antireflux surgery is being considered, or (3) there are atypical symptoms (e.g., chest pain, cough, wheezing).
    Management  life-style changes (elevation of the head of bed, avoiding large and late-night meals, stopping using alcohol, nicotine, caffeine, etc. + PPIs (omeprazole, lansoprazole, rabeprazole, etc.)
    H2 blockers, antacids and metoclopramide are inferior to PPIs
    If resistant to therapy preform Nissen fundoplication (or any other surgical procedure that tightens the LES)
    Link to surgery  if you decide to perform surgery for GERD, perform all the basic diagnostic studies before operating on the patient (barium swallow, esophagoscopy, pH monitoring and manometry)
    Surgical fundoplication (Nissen or Belsey wrap):
    Often performed laparoscopically. Indicated for patients who cannot tolerate medical therapy or who have persistent regurgitation.
    Contraindicated in patients with an esophageal motility disorder.
    Outcome: More than 50% of patients require continued acid suppressive medication, and > 20% develop new symptoms (dysphagia, bloating, dyspepsia).
    COMPLICATIONS
    Peptic strictures: Affect 8–20% of GERD patients; present with dysphagia. Dysphagia usually starts with solids followed by liquids. Young age and lack of alarming sysmptoms argue against a diagnosis of malignancy.
    Malignancies must be excluded via endoscopy and biopsy; can then be treated with endoscopic dilation followed by indefinite PPI therapy.
    Upper GI bleeding: Hematemesis, melena, anemia 2° to ulcerative esophagitis.
    Posterior laryngitis: Chronic hoarseness from vocal cord ulceration and granulomas.
    Asthma: Typically has an adult onset; nonatopic and unresponsive to traditional asthma interventions.
    Cough: Affects 10–40% of GERD patients, most without typical GERD symptoms.
    Noncardiac chest pain: After a full cardiac evaluation, consider an empiric trial of PPIs or ambulatory esophageal pH monitoring.
    Other: Barrett’s esophagus, adenocarcinoma
    Barrett’s esophagus
    Columnar metaplasia of the distal esophagus due to long-standing GERD
    Most common in Caucasian men > 55 years of age; overall incidence is greater in males than in females. The risk of adenocarcinoma is 0.5% per year.
    Risk factors include male gender, Caucasian ethnicity, and smoking.
    Increased risk of adenocarcinoma, requiring endoscopic surveillance
    Upper endoscopy: Suggestive but not diagnostic, as it is a histologic diagnosis. Salmon-colored islands or “tongues†are seen extending upward from the distal esophagus.
    Biopsy: Diagnostic.
    Shows metaplastic columnar epithelium and goblet cells.
    Specialized intestinal metaplasia on biopsy is associated with an ↑ risk of adenocarcinoma (not squamous).
    Management  Indefinite PPI therapy (GERD should be treated prior to surveillance, as inflammation may confound the interpretation of dysplasia).
    Adenocarcinoma surveillance is necessary only if patients are candidates for esophagectomy.
    Upper endoscopy with four-quadrant biopsies every 2 cm of endoscopic lesions.
    Screening (based on criteria from the American Society of Gastrointestinal Endoscopy) is as follows:
    After initial diagnosis, repeat EGD in one year for surveillance with biopsies.
    Proceed according to EGD findings:
    No dysplasia: Repeat survillence EGD and biopsy every 1 – 3 years.
    Low-grade dysplasia: Repeat EGD within six months. If findings are unchanged, extend surveillance to yearly intervals.
    High-grade dysplasia: Management is controversial but includes early esophagectomy or intensive endoscopic surveillance every three months until cancer is diagnosed, followed by esophagectomy.
    Verify with an expert pathologist. Ablative therapies may be attempted (e.g., photodynamic therapy, argon plasma coagulation, endoscopic mucosal resection).
    Zenker’s diverticulum
    Mucosal herniation above the cricopharyngeal region (false diverticulum)
    Regurgiation of undigested food eaten several days ago
    Halitosis
    Dysphagia (especially on initiation of swallowing)
    Most patients are > 50 yo.
    The best initial and most accurate tests  barium swallow showing outpouching of the mucosa
    DO NOT perform endoscopy or NG tube placement  risk of perforation
    Management  cricopharyngeal myotomy; diverticulectomy for large lesions
  14. Guest

    Guest Guest

    Esophagitis (Infectious)

    Most common cause is Candida albicans (other less common causes include Herpes and Cytomegaloviruses)
    Usually seen in patients with HIV infection and CD4 count <200/mm3
    Other, but less important risk factors include (less important for the purpose of USMLE):
    1. Diabetes
    2. Steroid treatment or chemotherapy
    3. Impaired emptying of the esophagus, as seen in achalasia
    Odynophagia or painful swallowing is the major manifestation
    If the patient is HIV positive  proceed directly to fluconazole trial (if effective it confirms the diagnosis of Candidal esophagitis)
    If fluconazole not effective or patient not HIV infected  perform endoscopy with biopsies to determine the exact etiology (suspect Herpervirus if you see intranucelar inclusions, or Cytomegalovirus if both intranuclear and intracytoplasmic inclusions are detected)
    As a general rule nearly all the more common causes of esophagitis are seen in patients with severe immunosuppression
    Management:
    1. Candida  fluconazole
    2. Herpes  acyclovir
    3. Cytomegalovirus  ganciclovir (or foscarnet)
    4. Idiopathic ulcers: Trial of prednisone.

    Esophagitis (Pill-induced)
    Most common causes include:
    1. Oral bisphosphonates (alendronate, pamidronate, --dronates)
    2. Iron sulfate
    3. Potassium chloride
    4. Aspirin and other NSAIDs
    5. Tetracyclines
    6. Vitamin C
    Diagnosis made by history of drug ingestion
    Management (prevention)  swallowing pills with plenty of water and remaining upright for a considerable period of time ( e.g. at least 30 min for bisphosphonates)
    Mallory-Weiss syndrome
    Linear mucosal tear at the squamocolumnar junction seen after vomiting, and less commonly after straining or coughing
    Hematemesis after an initial non-bloody vomitus
    May also present with melena if bleeding is >100ml, but not continued
    Next step in management  hemodynamic stabilization (IV fluid resuscitation with two large-bore needles, transfusion if low hematocrit, etc.)
    Best initial and most accurate test  esophageal endoscopy
    Management  usually resolves spontaneously with supportive treatment given only.
    If continued bleeding  direct epinephrine injection into the tear or cauterization (performed with the help of endoscopy)
    Boerhaave syndrome
    Esophageal wall rupture secondary to forceful vomiting (most common location is the left posterolateral wall of lower 1/3 of esophagus)
    More commonly esophageal perforation follows instrumentation, such as pneumatic dilation or endoscopy (iatrogenic esophageal rupture)
    Most common risk factor is excessive alcohol intake
    Sudden onset of lower thoracic/upper abdominal pain following a period of retching and vomiting (or instrumentation of the esophagus)
    Pain aggravated with swallowing
    Shortness of breath and cough are also common at presentation
    Cracking sound on auscultation coinciding with heartbeat (Hamman’s crunch)
    Pleural effusion (low pH, high amylase content, presence of food particles or gastric juice)
    Pneumomediastinum and subcutaneous emphysema
    Best initial test (if not already done in the test question)  chest X-ray showing left pleural effusion, pneumomediastinum and subcutaneous emphysema
    Most important diagnostic test (and usually the correct answer on test questions)  Gastrograffin swallow (water-soluble contrast)
    Most accurate diagnostic test (although rarely needed) CT scan
    Management  fluid resuscitation, broad-spectrum antibiotic administration, NG suction and immediate referral to the surgical unit
    Most important step in management  early diagnosis (within 24 hours of onset)

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