Stroke-like episodes in mitochondrial encephalomyopathy with lactic acidosis

Abstract

We described two patients (female, 47 years and male, 42 years) with mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS). Diagnosis was confirmed by genetic study (A3243G mitochondrial DNA mutation was found), muscle biopsy and elevated lactate level in the blood. Clinical picture of stroke-like episodes was presented by symptoms of mainly involvement of the posterior brain area (fluent and amnestic aphasia, hemianopia, paresis, ataxia), as well as by headache and epileptic seizures. In the first patient stroke-like episodes recurred but their symptoms almost completely regressed with time. The second patient had severe residual neurological deficit. Other clinical manifestations included hearing loss, memory deterioration, cardiomyopathy, fatigue and type 1 diabetes mellitus. MRI in acute period of stroke-like episodes found cortical lesions mainly in the posterior parts of the brain. They completely disappeared in the first case, but persisted in the second patient. The differential diagnosis of stroke-like episodes and ischemic stroke and approaches to treatment are discussed.