[Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes with delayed and decreased cerebral blood flow on cerebral angiography--a case report].

A 9-year-old girl was admitted to our hospital because of fever, headache, vomiting, and convulsive seizures. On admission, she was proved to have homonymous hemianopsia as well as elevated lactate and pyruvate levels in both serum and cerebrospinal fluid. Muscle biopsy study showed scattered ragged-red fibers and strongly succinatedehydrogenase-reactive blood vessels (SSV), suggesting systemic vascular involvement. She had a point mutation at nucleotide pair 3,243 in mitochondrial DNA extracted from muscle and blood samples. Brain CT and MRI showed a large abnormal area mimicking cerebral infarction in the region of the occipital cerebral artery. The cerebral lesion was assumed to be caused by vascular abnormality because of delayed and decreased cerebral blood flow together with vascular changes in her muscle biopsy.