关键词: 线粒体脑肌病伴高乳酸血症和卒中样发作; 丙戊酸钠; 药物陷阱; 花边征

Abstract: Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episode (MELAS) is a maternally inherited oxidative phosphorylation disorder caused by mitochondrial DNA mutations. In its early stage, MELAS often presents with seizures, headache, or stroke-like episodes, and is therefore prone to be misdiagnosed as seizure and inappropriate exposure to drugs with mitochondrial toxicity. This paper reports a 15-year-old male patient who initially presented with recurrent headache accompanied by convulsions. The patient had been treated at an external hospital with long-term oral sodium valproate for presumed migraine and epilepsy, but with poor clinical response. Subsequently, the patient developed symptoms of stroke-like episodes, including aphasia and hemianopia. Brain MRI revealed cortical migratory lesions extending beyond vascular territories, together with a characteristic “lace-like” sign. Combined with developmental retardation, elevated blood lactate, and the presence of the mitochondrial DNA m.3243A>G mutation, a definitive diagnosis of MELAS was established. Sodium valproate was discontinued, and mitochondrial-targeted supportive therapy centered on L-arginine was initiated, after which the patient showed short-term clinical improvement. Combined with literature review, this case highlights that MELAS and its potential drug-related pitfalls should be strongly suspected in adolescents with epilepsy who fail to respond to sodium valproate and show stroke-like imaging changes. Early genetic testing and timely adjustment of treatment strategies are essential.

Key words: Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episode; Sodium valproate; Drug-related pitfall; Lace-like sign