title: [Determination of the critical time point for efficacy of L-arginine infusion therapy in a case of MELAS with frequent stroke-like episodes].
abstract: MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes) is the most representative subtype of mitochondrial diseases. Administration of L-arginine (L-Arg) or a precursor of nitric oxide (NO) has been proposed as a promising medication for MELAS because one of the pathophysiological mechanisms is supposedly a decreased capacity for NO-dependent vasodilation. We experienced a girl with MELAS and frequent stroke-like episodes who was treated with L-Arg infusion. We evaluated the efficacy of L-Arg infusion therapy based on whether her headache and nausea were disappeared and neurological symptoms were improved within 24 hours of L-Arg administration. L-Arg infusions were effective in all four episodes when the treatment was started within 4 hours of the onset of stroke-like episodes. On the other hand, the infusion was effective in only one out of five episodes when the medication was delayed by more than 4 hours after the onset. Furthermore, the early administration of L-Arg resulted in better outcomes regarding new lesions determined by brain MRI. Our data suggest that L-Arg infusion may be most effective when it is started within 4 hours of the onset of neurological symptoms in the acute phase of MELAS. The study of a large number of episodes in many patients will be needed to determine the critical time point of L-Arg administration after the onset of the acute phase of MELAS.
authors.forename: Akira
authors.initials: A
authors.lastname: Sudo
authors.forename: Hitomi
authors.initials: H
authors.lastname: Sano
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Kawamura
mesh_terms: D001120:Arginine / Q000008:administration & dosage / Q000627:therapeutic use*; D002648:Child; D006801:Humans; D007262:Infusions, Intravenous; D017241:MELAS Syndrome / Q000175:diagnosis / Q000188:drug therapy*; D008279:Magnetic Resonance Imaging / Q000379:methods; D020521:Stroke / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D001120:Arginine