King-Denborough Syndrome: report of two Brazilian cases

Malignant hyperthermia in a 4-year-old girl during anesthesia induction with sevoflurane and succinylcholine for congenital ptosis surgery

Malignant hyperthermia (MH) is a rare pharmacogenic disorder of skeletal muscle calcium regulation, resulting from general anesthesia that can be fatal. Most cases are caused by administration of volatile anesthetics or depolarizing muscle relaxants.

It has been generally reported that both of sevoflurane and succinylcholine can induce the delayed onset of MH.

Here, we report a case of malignant hyperthermia in a four-year-old girl during anesthesia induction for unilateral congenital ptosis surgery, two minutes after sevoflurane and succinylcholine administration. The crisis was atypical but early recognized and managed by administration of dantrolene with symptomatic treatment.

Core myopathies and malignant hyperthermia susceptibility: a review

The core myopathies are a subset of myopathies that present in infancy with hypotonia and muscle weakness. They were formerly considered a rare type of congenital myopathy but are now recognized as being more prevalent. Due to their genetic linkage to mutations in the ryanodine receptor gene (RYR1), core myopathies (in particular, central core disease) carry a high risk of malignant hyperthermia susceptibility. In this review article, we describe the phenotypical, genetic, and histopathological characteristics of core myopathies and further describe the currently understood nature of their risk of malignant hyperthermia. We also review the level of suspicion a clinician should exhibit with a child who has a possible core myopathy or other congenital myopathy presenting for an anesthetic prior to a definitive genetic analysis. For this review article, we performed literature searches using the key words anesthesiology, core myopathies, pediatric neurology, malignant hyperthermia, genetics, ryanodine receptor, and molecular biology. We also relied on literature accumulated by the two authors, who served as hotline consultants for the Malignant Hyperthermia Hotline of the Malignant Hyperthermia Association of the United States (MHAUS) for the past 12 years.

Delayed onset malignant hyperthermia after sevoflurane

Malignant hyperthermia is a hypermetabolic response to inhalation agents (such as halothane, sevoflurane, and desflurane), succinylcholine, vigorous exercise, and heat. Reactions develop more frequently in males than females (2 : 1). The classical signs of malignant hyperthermia are hyperthermia, tachycardia, tachypnea, increased carbon dioxide production, increased oxygen consumption, acidosis, muscle rigidity and rhabdomyolysis. In this case report, we present a case of delayed onset malignant hyperthermia-like reaction after the second exposure to sevoflurane.

Central core disease: atypical case with respiratory insufficiency in an intensive care unit

Central core disease is a rare congenital myopathy characterized by formation of typical cores in myofibrils. We report an atypical case of central core disease with respiratory insufficiency in the late stage of congenital myopathy. A 13-year-old girl was admitted to the intensive care unit with the diagnosis of respiratory distress syndrome. Ventilatory support was initiated. After 2 weeks of follow-up, the Division of Pediatric Neurology was consulted owing to the failure to wean her from the ventilator. Clinical and electromyographic features were in favor of primary muscle disease. Muscle biopsy revealed typical cores in type 1 muscle fibers, which were diagnostic for central core disease. This case was presented to emphasize that patients with respiratory distress who cannot be weaned from the ventilator should be evaluated for central core disease with an atypical presentation.