AIIMS MAY 2008 Q & A With Explanations

Discussion in 'AIIMS Nov 2013' started by Meena., May 15, 2008.

  1. Sunil.

    Sunil. Guest

    An infant shows congenital absent thumb, radial deviation of wrist and anterior bowing of radius. All are done as diagnostic procedures except
    a) Platelet count
    b) Karyotyping
    c) ECHO
    d) Bone marrow biopsy
    Ans d



    Radial club hand
    The forearm is foreshortened, and the wrist is positioned in radial deviation. It is associated with thumb hypoplasia/absence.

    Clinical presentation of radial clubhand varies with the degree of radial deficiency and the presence of associated anomalies. Radial deficiency is the classic anomaly that is associated with systemic conditions. All forms, regardless of the degree of expression, warrant systemic evaluation.

    Syndrome Characteristics

    Table : Syndromes associated with radial deficiency

    Holt-Oram Heart defects, most commonly cardiac septal defects

    TAR Thrombocytopenia-absent radius syndrome. Thrombocytopenia present at birth, but improves over time.

    VACTERL Vertebral abnormalities, anal atresia, cardiac abnormalities, tracheoesophageal fistula, esophageal atresia, renal defects, radial dysplasia, lower limb abnormalities

    Fanconi anemia Aplastic anemia not present at birth; develops at about 6 years. Fatal without bone marrow transplant. Chromosomal challenge test now available for early diagnosis.

    The appropriate workup for associated conditions necessitates referral to pediatric subspecialists. The heart is evaluated by auscultation and echocardiography. The kidneys are examined by ultrasound, and the platelet status is assessed by blood count and peripheral blood smear. The most devastating associated condition is Fanconi anemia. Children with Fanconi anemia do not have signs of bone marrow failure at birth; therefore, the diagnosis is not initially apparent. The majority of children experience signs of aplastic anemia between the ages of 3 and 12 years (median age of 7 years). However, a chromosomal challenge test is available that allows detection of the disease prior to the onset of bone marrow failure. This assay subjects a sample of the child’s lymphocytes to diepoxybutane or mitomycin C, which cause chromosomes within Fanconi anemia cells to break and rearrange.
    Children with VACTERL syndrome warrant additional evaluation for spinal abnormalities, such as congenital scoliosis, and require radiographs of the spinal column. Children with VACTERL syndrome often appear similar to children with Fanconi anemia; they are of small stature, have feeding difficulties, and have similar musculoskeletal anomalies. Therefore, a chromosomal challenge test is warranted in a child with a presumed diagnosis of VACTERL syndrome.

    Special Investigations for Radial and thumb hypoplasia
    • Chromosome analysis – basic G-banding to exclude trisomy 18, triplidy, del13q and other visible abnormalities.
    • Additional cytogenetic analysis for Fanconi anaemia, Robert syndrome, Baller Gerold syndrome
    • Hematological investigation – full blood count, platelet analysis
    • Xray of the affected limb, consider chest and vertebral Xrays: vertebral abnormalities (VACTERL), cardiac enlargement, shoulder girdle(Holt Oram)
    • Cardiac ECHO and ECG – especially in the presence of murmur or possibility of Holt Oram syndrome or if there is tracheo-esophageal fistula.
    • Renal USG – VATER and fanconi anaemia

    About Thrombocytopenia with absent radii (TAR)Thrombocytopenia presents at birth and it improves with age. It is also a radial ray defect, the radii are absent but mostly thumb is normal. So our case is most probably not TAR syndrome. But still I feel thrombocytopenia needs to be ruled out as there can be slight variation in presentation of all syndromes.

    Hence in an infant with radial club hand platelet count, karyotyping and ECHO is warranted. Bone marrow biopsy is indicated for Fanconi anaemia which is a prominent cause of this deformity. But since it does not present before 6-7 yrs age it is not needed in an infant.
  2. Sunil.

    Sunil. Guest

    Choroidal neovascularisation is seen in all except - pptions were trauma, myopia, hypermetropia and angioid streaks.


    Causes

    Virtually any pathologic process that involves the RPE and damages the Bruch membrane can be complicated by CNV.

    * Degenerative conditions

    o ARMD
    o
    o Myopia
    o
    o Angioid streaks
    *
    * Inflammatory or infectious conditions

    o Histoplasmosis
    o
    o Sarcoidosis
    o
    o Multifocal choroiditis
    o
    o PIC
    *
    * Choroidal tumors

    o Nevi
    o
    o Melanoma
    o
    o Hemangioma
    o
    o Osteoma
    *
    * Trauma

    o Choroidal rupture
    o
    o Laser photocoagulation
    *
    * Idiopathic
  3. Joya.

    Joya. Guest

    Ext oblique,int oblique,t.abdominis are all only retracted laterally during surgery of
    A- lumbotomy approach for renal access
    B- laparoscopic approach for renal access
    C- surgery for spigelian hernia
    D- percutaneous approach for renal access


    RIGHT LAPAROSCOPIC NEPHRECTOMY IN LIVING DONOR

    he surgical procedure starts with the patient
    in partial left lateral decubitus (30 degrees) under
    general anesthesia and continuous peridural anesthe-
    sia. The transperitoneal access was used in all cases.
    The skin incision must be extended to the same size
    in centimeters as the size of the assistant surgeon’s
    glove, for allowing the insertion of the device de-
    signed for introducing the hand. The incision begins
    at the lateral margin of the rectus muscle of the abdo-
    men, 2 cm above the pubic symphysis, and is ob-
    liquely extended until the antero-superior iliac spine.
    The external oblique, internal oblique and transverse
    muscle of the abdomen are separated, the peritoneum
    is opened and the colon is displaced medially. The
    ureter is identified, isolated with a Penrose drain and
    dissected superiorly and inferiorly until it crosses the
    iliac vessels. Only then is the first 10-mm trocar (cam-
    era) introduced into the abdominal cavity through an
    incision made at the level of the umbilical scar, and
    guided by the surgeon’s hand, which was introduced
    in the inguinal incision. The device that allows the
    hand to be introduced in the cavity is then installed
    according to the manufacturer’s instructions.
  4. Meena.

    Meena. Guest

    A pH of 3.5 has the following effect on lysophospholipid in biological membranes
    a)there is increase in dipole moment
    b)decrease in dipole moment
    c)no effect

    ans-increase in dipole moment

    For pH<4, far from the isoelectric point, the protein is charged and repulsive interactions, opposite to aggregation, become dominant. Therefore, the observed increase of dipole moment suggest that the protein might be partially expanded by repulsion among positively charged groups.
    ref
    journal colloid and surfaces

    Influence of pH on lysozyme conformation revealed by dielectric spectroscopy
  5. Meena.

    Meena. Guest

    the most resistant to chemotherapy
    a)fibrous histiocytoma
    b)osteosarcoma
    c)...........
    d)..........
    what are other two choices?


    Neoadjuvant chemotherapy in malignant fibrous histiocytoma of bone and in osteosarcoma located in the extremities: Analogies and differences between the two tumors
    P. Picci1, G. Bacci2,, S. Ferrari2 and M. Mercuri3

    1Laboratory of Oncologic Research, Istituto Ortopedico Rizzoli Bologna, Italy
    2Department of Chemotherapy, Istituto Ortopedico Rizzoli Bologna, Italy
    35th Department of Orthopaedics, Istituto Ortopedico Rizzoli Bologna, Italy

    Correspondence to: P Picci, MD Laboratory of Oncologic Research Istituto Ortopedico Rizzoli Via di Barbiano 1/10 40136 Bologna Italy E-mail: [email address in profile] pt.tizeta.it

    BACKGROUND: Malignant fibrous histiocytoma (MFH) is a rare bone tumor usually treated like osteosarcoma. Studies on analogies and differences between the two tumors have seldom been reported.

    PATIENTS AND METHODS: Between March 1982 and December 1994, 51 patients with high-grade MFH of bone and 390 with high-grade osteosarcoma were treated with the same regimen of neoadjuvant chemotherapy. All of the tumors in both groups were located in the limbs. Preoperative chemotherapy was performed according to three different, successively activated, regimens consisting of MTX/CDP intraarterially, MTX/CDP/ ADM, and MTX/CDP/ADM//IFO.

    RESULTS: The rate of limb salvage was the same in both the MFH (92%) and osteosarcoma (85%) patients. MFH showed a statistically significantly lower rate of good histologic response, 90% or more tumor necrosis (27% vs. 67%, P = 0.00001) for all three regimens. Despite this low chemosensitivity, the disease- free survivals of the two neoplasms were similar (67% vs. 65%).

    CONCLUSIONS: In terms of histologic response to primary chemotherapy, MFH has a lower chemosensitivity than osteosarcoma. Nevertheless, the two tumors have similar prognoses when treated with chemotherapy regimens based on MTX, CDP, ADM and IFO.
  6. Meena.

    Meena. Guest

    Keratin +ve epithelial mediastinal tumor with lymphocytic infiltration is probably a Thymoma. Carcinoid is difficult to rule out though. The other options in the question were hematologic malignancies. They are sarcomas and are not likely to be keratin-positive.


    i remember there was some word aborescent in the question,cant remember exactly,does any one recollect?

    Histologic Findings

    Thymoma

    Thymomas arise from thymic epithelial cells. They are generally composed of 2 cell types, epithelial and lymphocytic. The morphology of the epithelial cells can be round, oval, or spindle-shaped. The cells are rather large and tend to organize into clusters. They have vesicular nuclei with small nucleoli and cytoplasm that is eosinophilic or amphophilic. The spindle-shaped variety of epithelial cell is often arranged in a whorl-type pattern. Individual cells have an appearance similar to that of fibroblasts. The lymphocytic component of thymomas is made up of mature lymphocytes with no significant atypia.

    Thymomas are generally classified as predominantly epithelial, predominantly lymphocytic, mixed lymphoepithelial, and spindle cell type, which is a variant of the epithelial type and is composed mostly of the spindle-shaped epithelial cells. Other microscopic features that have been noted include Hassall corpuscles, keratinizing squamous epithelium, rosettes, glands and pseudoglands, cysts, papillary structures, and germinal centers. These features do not appear to have any significance in predicting the activity of the tumor.

    Cellular makeup is not the prime consideration in the determination of a thymoma's malignant or indolent potential. The most important features are the gross pathologic characteristics. These include encapsulation of the tumor and fixation or invasion of adjacent structures. While no thymoma is truly benign, well-encapsulated thymomas with no evidence of invasion of the capsule are considered much less aggressive. Any evidence of invasion of the capsule or adjacent structures suggests a much more malignant level of activity.

    Immunohistochemical staining methods with antikeratin antibodies can be helpful in the histologic identification of a thymoma. A number of thymic epithelial markers, such as cytokeratin, thymosin beta-3, thymosin alpha-1, and epithelial membrane antigen, have also been used.

    Thymic carcinomas

    The various types of carcinoma that occur in the thymus are quite rare. Squamous cell carcinoma of the thymus resembles typical squamous cell carcinoma. Well-differentiated tumors display prominent lobulation and are composed of large polygonal cells in groups or cords connected by intercellular bridges. The nuclei are vesicular or densely pigmented and have distinct nucleoli. The cytoplasm is eosinophilic, and keratin "pearls" are common. These tumors may be only locally invasive.

    Poorly differentiated squamous cell tumors are more aggressive locally, have little of the lobular architecture found in the well-differentiated form, and may metastasize to distant sites. These tumors have a more disarrayed architecture and cellular atypia. Distinct fibrous septae or bridges within the tumor often are lacking. Cytoplasm is sparse and amphophilic. Keratin pearls are not seen.

    Lymphoepitheliomalike carcinoma of the thymus is made up of dense sheets of polygonal epithelial cells with indistinct cytoplasmic membranes. These cells have round vesicular nuclei, large eosinophilic nucleoli, and amphophilic cytoplasm. The tumors always have groups of lymphocytes interspersed throughout. These tumors are virtually identical to lymphoepitheliomas located in the nasopharynx.
  7. Meena.

    Meena. Guest

    diabetes in pregnancy all EXCEPT
    a)glucose challenge test is done betn 24-28 wks
    b)50 gm of sugar given after post meal as screening test
    c)insulin resistance improves with pregnancy


    Human pregnancy is characterized by a series of metabolic changes that promote adipose tissue accretion in early gestation, followed by insulin resistance and facilitated lipolysis in late pregnancy. In early pregnancy, insulin secretion increases, while insulin sensitivity is unchanged, decreased, or may even increase (1,2). However, in late gestation, maternal adipose tissue depots decline, while postprandial free fatty acid (FFA) levels increase and insulin-mediated glucose disposal worsens by 40–60% compared with prepregnancy (2). The ability of insulin to suppress whole-body lipolysis is also reduced during late pregnancy (3), and this is further reduced in GDM subjects (4), contributing to greater postprandial increases in FFAs, increased hepatic glucose production, and severe insulin resistance (2,5–7). Although various placental hormones have been suggested to reprogram maternal Physiology to meet fetal needs, the cellular mechanisms for this complex transition remain obscure (8). Further, the critical molecular mechanisms involved in increasing maternal lipid flux in obese women throughout pregnancy that may underlie skeletal muscle insulin resistance and increased fetal fuels are just beginning to be inv
  8. Meena.

    Meena. Guest

    WHICH teratogen causes deafness?
    a)valporate
    b)chloroquine
    c)alcohol
    d)warfarin

    ans:alcohol

    ref

    The MIT encyclopedia of communication disorders
    By Raymond D. Kent


    p493 those agents currently under suspicion but not proven to be ototoxic
    are tetracyclines,chloroquine,chemotherapeutic drug ,diuretics.

    about alcohol book writes:
    sensorineural hearing loss has been reported at higher rates in chidren with fetal alcohol syndrome
  9. Sujit.

    Sujit. Guest

    pt presents with mediastinal mass with sheets of lymphocytes and an arborizing pattern of keratin reactivity.diagnosis?
    a)thymoma
    b)thymic carcinoid
    c)primary mediastinal lymphoma
    d)hodgkin lymphoma


    ref


    Editors: Mills, Stacey E.; Carter, Darryl; Greenson, Joel K.; Oberman, Harold A.; Reuter, Victor E.; Stoler, Mark H.
    Title: Sternberg's Diagnostic Surgical Pathology , 4th Edition


    Additional observations that aid in the recognition of Lymphocyte Predominant Thymoma(LPT) are the presence of intratumoral, perivascular serum “lakes”); microcysts; numerous dispersed mast cells as seen with the chloroacetate esterase method; and “medullary differentiation” (multifocal loose aggregates of lymphocytes that simulate thymic medulla on low-power microscopy)
    Immunostaining for keratin reveals a finely arborizing network of interconnecting epithelial cell processes in LPT

    ans :thymoma
  10. Sujit.

    Sujit. Guest

    Which of the following is the most effective agent to treat hypertension in this patient?

    A) Methyldopa

    B) Labetalol

    C) Enalapril

    D) Amlodipine

    E) Atenolol

    The correct answer is: B

    52% of the people have answered this question correctly

    Explanation:

    In pregnant patients with a hypertensive crisis, either hydralazine or labetalol are the antihypertensive drugs of choice.

    ACE inhibitors are contraindicated in pregnancy (Choice C).

    (Choice A) Methyldopa is the preferred agent for oral therapy in mild to moderate hypertension. Calcium channel blockers are added to methyldopa as second line agents (Choice D).

    (Choice E) Atenolol is an oral agent (in USA) and is not indicated in the acute setting. Although beta-blockers are considered to be safe, there are some reports of impaired fetal growth, especially with atenolol if used in the early part of a pregnancy.

    Educational Objective:
    Either hydralazine or labetalol are the antihypertensive drugs of choice in the acute setting in a pregnancy. Methyldopa is preferred for oral therapy in mild to moderate hypertension in a pregnancy.
  11. Sujit.

    Sujit. Guest

    A 22-year-old primigravida is hospitalized at 34 weeks gestation because of blurred vision, headache, and pain in the right upper quadrant of the abdomen. Her temperature is 36.7 C ([snip] F), blood pressure is 220/110 mmHg, pulse is 80/min, and respirations are 20/min. The fundoscopic exam is normal. On examination, you note swelling of both her hands and her face, bilateral exaggeration of deep tendon reflexes with clonus, and a positive Babinski. The pelvic exam shows 50% effacement, and 3 cm dilation of the cervix. While getting IV access, the patient started to have generalized tonic-clonic seizures. An airway is secured, and breathing is present. Urinalysis revealed proteinuria of 3+ .

    Item 1 of 4

    Which of the following is the most effective strategy to decrease this patient"s risk for developing further complications?

    A) Check vital signs every four hours

    B) Start magnesium sulfate infusion

    C) Speed vaginal delivery

    D) Start parenteral clonidine

    E) Start phenytoin infusion

    The correct answer is: C

    41% of the people have answered this question correctly

    Explanation:

    This patient was admitted to the hospital because she has a severe preeclampsia, which was later complicated with eclampsia. Patients with severe preeclampsia are at greater risk of developing eclampsia. The first priority in patients with eclampsia or postictal coma is respiratory and cardiovascular resuscitation. Anticonvulsant medications can be administered after placing two large-bore needles in the patient. The most effective agent used in these cases is magnesium sulfate; however, the most effective treatment to prevent further complications is to accelerate delivery (Choice C). Eclampsia can cause several other complications besides seizures, such as disseminated intravascular coagulopathy, acute renal failure, hepatocellular injury, liver rupture, intracerebral hemorrhage, etc. Magnesium sulfate prevents seizures, but it will not stop the pathologic process.

    Again, magnesium sulfate will be beneficial, but not as effective as pregnancy termination (Choice B). This would have been a correct choice if the question was asked about the next step in the management of this patient, because the hemodynamic stability and seizure control are important before attempting delivery.

    Clonidine is not indicated in this setting (Choice D). Either hydralazine or labetalol are the antihypertensive drugs of choice.

    Phenytoin or diazepam is not as effective as magnesium sulfate in controlling seizures; but, again, seizures are not the only complication of eclampsia. Speeding up the delivery is the most important (Choice E).

    Frequent monitoring of vital signs is part of the management, but it will not prevent the patient from developing further complications (Choice A).

    Educational Objective:
    Eclampsia is a serious complication of pregnancy. If the patient is in the third trimester, especially in the last six weeks, termination of pregnancy is advised in order to stop the pathologic process. There is no pharmacologic therapy more effective than this intervention.

    5. (QId - 221)

    Item 2 of 4

    Which of the following is the most effective agent to treat hypertension in this patient?

    A) Methyldopa

    B) Labetalol

    C) Enalapril

    D) Amlodipine

    E) Atenolol

    The correct answer is: B

    52% of the people have answered this question correctly

    Explanation:

    In pregnant patients with a hypertensive crisis, either hydralazine or labetalol are the antihypertensive drugs of choice.

    ACE inhibitors are contraindicated in pregnancy (Choice C).

    (Choice A) Methyldopa is the preferred agent for oral therapy in mild to moderate hypertension. Calcium channel blockers are added to methyldopa as second line agents (Choice D).

    (Choice E) Atenolol is an oral agent (in USA) and is not indicated in the acute setting. Although beta-blockers are considered to be safe, there are some reports of impaired fetal growth, especially with atenolol if used in the early part of a pregnancy.

    Educational Objective:
    Either hydralazine or labetalol are the antihypertensive drugs of choice in the acute setting in a pregnancy. Methyldopa is preferred for oral therapy in mild to moderate hypertension in a pregnancy.

    6. (QId - 222)

    Item 3 of 4

    During labor, the patient had another seizure. Which of the following is the most appropriate pharmacotherapy in order to avoid seizure recurrence in these patients?

    A) Phenytoin

    B) Magnesium sulfate

    C) Phenobarbital

    D) Diazepam

    E) Valproic acid

    The correct answer is: B

    72% of the people have answered this question correctly

    Explanation:

    Anti-seizure prophylaxis in a patient with eclampsia has been a topic of prolonged debate. Recently, some studies have confirmed that magnesium sulfate is not only the best anticonvulsant medication for patients with eclampsia, but it is also the more effective agent to prevent further seizures (Choice B).

    With diazepam, there is a greater risk of respiratory depression. Magnesium sulfate is proven to be more effective and to have a low neonatal morbidity. Diazepam is more useful in the setting of status epilepticus, or if the patient has contraindications to use magnesium sulfate, such as myasthenia gravis (Choice D).

    Phenytoin can be useful, but it is not as effective as magnesium sulfate (Choice A). Phenobarbital is reserved only for those cases in which seizures persist, despite the use of magnesium sulfate, diazepam, or phenytoin (Choice C). Valproic acid is not part of the therapy of eclampsia (Choice E).

    Educational Objective:
    The best medication to prevent further seizures in a patient with eclampsia is magnesium sulfate. Diazepam or phenytoin can be added to the therapy if seizures persist, even though the use of diazepam is limited because of depressant effects on the fetus.

    7. (QId - 223)

    Item 4 of 4

    Presence of which of the following is considered an extremely ominous sign/feature of this condition?

    End of Set

    A) Increased PGI 2 and Thromboxane A 2 ratio

    B) Retinal hemorrhages

    C) Glomerular capillary endotheliosis

    D) Microangiopathic hemolytic anemia

    E) Subcapsular hematoma of the liver

    The correct answer is: B

    40% of the people have answered this question correctly

    Explanation:

    This patient has preeclampsia complicated by eclampsia. Retinal hemorrhage is considered to be an extremely ominous sign, because it reflects the vascular damage that has occurred in other organs. Retinal vasospasm can also be seen in preeclampsia and can be visualized on ophthalmoscopic examination.

    (Choice A) Opposite to normal pregnancy, the PGI 2 to Thromboxane A 2 ratio decreases and does not increase. This change results in an increase in peripheral resistance and, thus, clinical symptoms and complications of preeclampsia and eclampsia. A deficiency in nitric oxide, as well as an increase in Endothelin-I, have also been incriminated -- the former being a vasodilator and the latter a potent vasoconstrictor.

    (Choice C) Glomerular capillary endotheliosis is the typical glomerular lesion of preeclampsia/eclampsia. It involves a marked swelling of the glomerular capillary endothelium and deposits of fibrinoid material in and beneath the endothelial cells. The glomerular diameter is increased on light microscopy, with endothelial and mesangial cell swelling.

    (Choice D) Microangiopathic hemolytic anemia can occur in preeclampsia and eclampsia, but it is not considered an ominous sign. It results from the injury of RBC by the damaged endothelium that is usually associated with the condition.

    (Choice E) Vasoconstriction of the hepatic vasculature can result in necrosis and hemorrhage of the periportal spaces and, ultimately, subcapsular hematoma.

    Educational Objective:
    Retinal hemorrhage is considered to be an extremely ominous sign of preeclampsia/eclampsia.
  12. Sujit.

    Sujit. Guest

    Vasopressin and Other Agents Affecting the Renal Conservation of Water: Introduction




    The three drug classes most commonly implicated in drug-induced SIADH include psychotropic medications (e.g., fluoxetine, haloperidol , and tricyclic antidepressants), sulfonylureas (e.g., chloropropamide), and vinca alkaloids (e.g., vincristine and vinblastine). Other drugs strongly associated with SIADH include thiazide diuretics, clonidine, enalapril, ifosphamide, and methyldopa. In a normal individual, an elevation in plasma vasopressin per se does not induce plasma hypotonicity because the person simply stops drinking owing to an osmotically induced aversion to fluids. Therefore, plasma hypotonicity only occurs when excessive fluid intake (oral or intravenous) accompanies inappropriate secretion of vasopressin.




    Treatment of hypotonicity in the setting of SIADH includes water restriction, intravenous administration of hypertonic saline, loop diuretics (which interfere with the concentrating ability of the kidneys), and drugs that inhibit the effect of vasopressin to increase water permeability in the collecting ducts. To inhibit vasopressin's action in the collecting ducts, demeclocycline, a tetracycline, currently is the preferred drug.
  13. dutta.

    dutta. Guest

    most common tumor during pre-puberty

    most common tumor during pre-puberty
    a)endodermal sinus tumor
    b)teratoma
    c)embryonalcarcinoma
    d)seminoma


    ans:teratoma

    ref
    p442

    Editors: Halperin, Edward C.; Constine, Louis S.; Tarbell, Nancy J.; Kun, Larry E.
    Title: Pediatric Radiation Oncology, 4th Edition


    Teratomas (from Greek teratos, “monster,” and onkoma, “swelling”) are the most common pediatric GCTs.


    yolksac [endodermal sinus tumor]is also germ cell tumor
  14. dutta.

    dutta. Guest

    good man gilman

    11th edn


    Carbamazepine and chlorpropamide also enhance the antidiuretic effects of vasopressin by unknown mechanisms. In rare instances, chlorpropamide can induce water intoxication.




    Chlorpropamide, an oral sulfonylurea, potentiates the action of small or residual amounts of circulating vasopressin and will reduce urine volume in more than half of all patients with central DI. A dose of 125 to 500 mg daily is particularly effective in patients with partial central DI. If polyuria is not controlled satisfactorily with chlorpropamide alone, addition of a thiazide diuretic (see Chapter 28) to the regimen usually results in an adequate reduction in the volume of urine.


    The major V2-receptor-mediated adverse effect is water intoxication, which can occur with desmopressin or vasopressin. In this regard, many drugs, including carbamazepine, chlorpropamide, morphine, tricyclic antidepressants, and NSAIDs, can potentiate the antidiuretic effects of these peptides
  15. dutta.

    dutta. Guest

    GOODMAN GILMAN ,11TH ED

    GOODMAN GILMAN ,11TH ED

    CHAPTER
    Vasopressin and Other Agents Affecting the Renal Conservation of Water: Introduction




    The three drug classes most commonly implicated in drug-induced SIADH include psychotropic medications (e.g., fluoxetine, haloperidol , and tricyclic antidepressants), sulfonylureas (e.g., chloropropamide), and vinca alkaloids (e.g., vincristine and vinblastine). Other drugs strongly associated with SIADH include thiazide diuretics, clonidine, enalapril, ifosphamide, and methyldopa. In a normal individual, an elevation in plasma vasopressin per se does not induce plasma hypotonicity because the person simply stops drinking owing to an osmotically induced aversion to fluids. Therefore, plasma hypotonicity only occurs when excessive fluid intake (oral or intravenous) accompanies inappropriate secretion of vasopressin.




    Treatment of hypotonicity in the setting of SIADH includes water restriction, intravenous administration of hypertonic saline, loop diuretics (which interfere with the concentrating ability of the kidneys), and drugs that inhibit the effect of vasopressin to increase water permeability in the collecting ducts. To inhibit vasopressin's action in the collecting ducts, demeclocycline, a tetracycline, currently is the preferred drug.

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