BACKGROUNDMalignant hyperthermia (MH), manifesting as MH crisis during and/or after general anesthesia, is a potentially fatal disorder in response to volatile anesthetics and depolarizing muscle relaxants. Though typical features of MH episode can provide clues for clinical diagnosis, MH susceptibility is confirmed by in vitro caffeine-halothane contracture test (CHCT) in western countries. It is traditionally thought that MH has less incidence and fewer typical characteristics in Chinese population than their western counterparts because of the different genetic background. In this study, we investigated the clinical features of MH in Chinese cases and applied the clinical grading scale and CHCT for diagnosis of MH.

METHODSA cluster of three patients with MH, from January 2005 to December 2007, were included in the study. Common clinical presentations and the results of some lab examinations were reported in detail. The method of the clinical grading scale of diagnosis of MH was applied to estimate the qualitative likelihood of MH and predict MH susceptibility. Muscle fibers of femoral quadriceps of the patients were collected and CHCT was performed to confirm the diagnosis of MH.

RESULTSThe clinical grading scales of diagnosis of the disease for these cases were all ranked grade D6, suggesting almost diagnosed ones. And the results of caffeine test were positive correspondingly, indicating that the patients should be diagnosed as MH susceptibility (MHS) according to diagnostic criteria of the North America MH group, which were already confirmed by clinical presentations and biochemical results.

CONCLUSIONSThese Chinese cases manifest as MH crisis. The clinical grading scale of diagnosis of MH may provide clues for clinical diagnosis. CHCT can also be used in confirming diagnosis of MH in Chinese cases though they have different genetic background from their western counterparts.