[Neurological aspects of malignant hyperthermia. Clinics, physiopathology, genetics]

Malignant hyperthermia, a disease formerly considered to occur almost exclusively in an anesthesia setting, has been observed in wider contexts due to progress in screening tests and genetics. Different neurological and neuromuscular conditions, with and even without hyperthermia, have been considered to belong to the disease, including overt or infraclinical signs of myopathies, and most significantly central core disease. Exercise-induced malignant hyperthermia is another similar syndrome as are syndromes with isolated exercise intolerance in young subjects, certain rhabdomyolysis syndromes and certain cases of sudden infants death syndrome. The pathophysiological mechanism would involve excessive calcium release from the sarcoplasmic reticulum caused by a protein structure anomaly in the ryanodin receptor, a non-energy dependent channel. Genetic studies have localized the ryanodin receptor gene anomaly on chromosome 19 in man in 30 to 40 p. 100 of the families. Other mutations with other chromosomic localizations are however known. Management of suspected malignant hyperthermia includes muscle biopsy and well-defined contraction tests.