Effects of l -arginine on the acute phase of strokes in three patients with MELAS

The primary cause for strokelike episodes in young patients with MELAS (myopathy, encephalopathy, lactic acidosis, and strokelike episodes)—whether mitochondrial cytopathy, angiopathy, or both—remains controversial. Based on a hypothesis that strokelike episodes in MELAS are caused by segmental impairment of vasodilation in intracerebral arteries, we administered l-arginine to three patients with MELAS in the acute phase of stroke (within 1 hour of onset) and evaluated effects on clinical course, biochemical measurements, and functional cerebral hemodynamics according to 99mTc-ECD SPECT. ### Patients. Patient 1 was a 17-year-old woman referred to the hospital for periodic vomiting, hemiconvulsion, and short stature (below 2.7 SD). Patient 2 was an 18-year-old woman who was admitted to the hospital for generalized muscle weakness, periodic vomiting, hemiparesis, and short stature (below 1.5 SD). Patient 3 was a 15-year-old boy referred to our hospital for hemiblindness, hemiconvulsions, vomiting, and short stature (below 2.8 SD). All patients showed extensive calcification in the basal ganglia, lactic acidosis (3.8 to 5.6 mmol/L; normal range …