Screening test for malignant hyperthermia in patients with persistent hyperCKemia: A pilot study

INTRODUCTION: Persistently elevated serum creatine kinase (CK) is frequently associated with predisposition to malignant hyperthermia (MH). We investigated whether a minimally invasive metabolic test is suitable to diagnose MH susceptibility among patients with hyperCKemia. METHODS: Thirty-nine participants were included: 10 were MH susceptible (MHS); 21 MH were non-susceptible (MHN); and 8 had MHN with persistent hyperCKemia >500 U/L. Microdialysis probes were inserted into the vastus lateralis muscle, and halothane or caffeine was injected via an attached microtubing catheter. Lactate concentrations in dialysis samples were measured spectrophotometrically. RESULTS: Baseline lactate did not differ between the groups. After local application of halothane or caffeine, a significant lactate increase was detected only in the MHS group. CONCLUSIONS: Test results were not influenced by hyperCKemia. To avoid risks and complications of a surgical muscle biopsy this microdialysis test might be a useful screening tool for MH susceptibility among patients with persistent CK elevation.