L-arginine efficiency in MELAS syndrome. A case report

Introduction. - Mitochondrial encephalomyopathy lactic acidosis and stoke-like episodes (MELAS) is a rare neurodegenerative disease caused by mutations of mitochondrial DNA. Case report. - We report the case of a 12-year-old child with MELAS syndrome who presented with recurrent migraine-like headache and sudden blindness suggesting stroke-like episodes. Furthermore, he developed progressive muscular impairment with bilateral hearing loss. Serum lactate and pyruvate levels were elevated and the muscle biopsy showed an aspect of red-ragged fibers with Gomori trichrome. Brain imaging showed calcifications of basal ganglia on the CT scan and a parieto-occipital high signal on diffusion-weighted MRI. A genetic analysis was not performed but the presence of hearing loss in the patient's mother was suggestive of maternal transmission. Stroke-like episodes in the form of migraine-like headache and blindness were the patient's major complaint and did not improve despite analgesic drugs. After oral administration Of L-arginine at the dose of 0.4 mg/kg per day, stroke-like symptoms totally and rapidly disappeared. Discussion. - The efficiency Of L-arginine in stroke-like episodes was initially reported then confirmed in a controlled study. The pathophysiology of stoke-like episodes and the mechanisms underlying the action Of L-arginine are discussed. (C) 2008 Elsevier Masson SAS. All rights reserved.