Shortly after the administration of an inhalational

Discussion in 'MRCS Forum' started by Lona., Dec 9, 2007.

  1. Lona.

    Lona. Guest

    Shortly after the administration of an inhalational anesthetic and succinylcholine for intubation prior to an elective inguinal hernia repair in a 10-yrs-old boy, he becomes markedly febrile and displays a tachycardia of 160, and his urine changes color to a dark red. The correct approach should be-
    a- Complex the procedure but pretreat with dantrolene prior to future elective surgery
    b- Administer inhalational anesthetic agents
    c- Hyperventilate with 100% oxygen
    d- Acidify the urine to prevent myoglobin precipitation in the renal tubules
  2. Lona.

    Lona. Guest

    Answer: d. (Schwartz, 7/e, pp 448, 499) The cause of malignant hyperthermia is unknown, but it is associated with inhalational anesthetic agents and succinylcholine. It may develop in an otherwise healthy person who has tolerated previous surgery without incident. It should be suspected in the presence of a history of unexplained fever, muscle or connective tissue disorder, or a positive family history (evidence suggests an autosomal dominant inheritance pattern). In addition to fever during anesthesia, the syndrome includes tachycardia, increased O2 consumption, increased CO2 production, increased serum K+, myoglobinuria, and acidosis. Rigidity rather than relaxation following succinylcholine injection may be the first clue to its presence. Treatment of malignant hyperthermia should include prompt conclusion of the operative procedure and anesthesia, hyperventilation with 100% oxygen, and administration of intravenous dantrolene. The urine should be alkalinized to protect the kidneys from myoglobin precipitation. If reopration is necessary, the physician should premedicate heavily, alkalinize the urine, and avoid depolarizing agents such as succylcjoline pretreatment for 24 h with dantrolene is helpful; it is thought to act directly on muscle fiber to attenuate calcium release.

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