Mitochondrial encephalomyopathy, lactic acidosis and stroke in adults: two cases.

Two previously healthy women are described who in their late thirties suffered transient strokelike episodes, consisting of initial headache and vomiting, with various subsequent neurological signs that were only partially reversible. Investigations revealed elevated serum creatine kinase, lactic acidosis, hypertriglyceridaemia, and ragged red fibres in the muscle biopsy specimens. In both patients in vitro studies were performed on intact muscle mitochondria and muscle homogenate. Only in one was a mitochondrial defect found, located at the level of coenzyme Q. We conclude that these patients suffered from adult-onset mitochondrial encephalopathy, lactic acidosis and strokelike episodes (MELAS syndrome). Although the syndrome is often associated with long-standing neurological multisystem disease from childhood onwards, it should also be suspected in adults with strokelike signs of otherwise unexplained origin.