The value of ultrasound for the diagnosis of malignant hyperthermia.

A highly feared complication of anesthesia is malignant hyperthermia (MH). In vivo identification of MH is achieved sonographically. Transducers of 7.5 and 5 MHz were used for transverse cuts of the upper and lower leg. Sonographic changes were found in 22 out of 33 subjects from 12 families affected by MH, including several positive subjects not previously known to be subject to MH. The ultrasound image reveals increased parenchymal echogenicity, with obscuring of intramuscular septum and fascia. Myosonography allows noninvasive screening of family members of subjects with known MH; potentially dangerous challenge testing or biopsy may be reserved for specific indications.