In vitro contraction test for malignant hyperthermia in patients with unexplained recurrent rhabdomyolysis

A few cases of non-anaesthetic-induced rhabdomyolysis in humans, predisposed to malignant hyperthermia (MH), have been described in literature. We studied a group of 6 consecutive patients with unexplained and recurrent attacks of rhabdomyolysis with the test used to determine susceptibility to MH, the in vitro contraction test (IVCT). The results of the IVCT showed 5 of these 6 patients to be MH susceptible. In cultured muscle cells from one of these patients a disturbed calcium homeostasis could be demonstrated. The relation between MH and recurrent rhabdomyolysis is discussed.