Abstracts

Epilepsia partialis continua (EPC) is a condition characterized by continous myoclonic or clonic jerks repeated at short intervals followed by a slowly progressive neurological disorder and eventual progressive brain atrophy of the involved hemisphere. We report three patients with EPC associated with a defect of complex I of the mitochondrial respiratory chain We report the clinical, neuroradiological, biochemical and pathological features of our three patients. To study the mitochondrial respiratory chain complexes, muscle samples were analysed spectrophotometrically with a normalisation to the activity of citrate synthetase Three patients (two boys, one girl) started to present continuous myoclonic jerks at age of 8 months, 11 months and 6 years, respectively. Two of three had a previous developmental delay. Neurological examination ad first admission revealed extrapyramidal symptoms (choreoathetosic movements) in our three patients. There was no symptom of myopathy. Two patients presented initially a hepatic cytolysis. Initial biological investigations suggested a possible mitochondrial dysfunction (lactacte in blood and in CSF, lactate/pyruvate ratio, ketone bodies). Initial EEG showed in two of three patients, a continuous discharge of right occipital periodic spikes (0,5 [ndash] 1 Hz). MRI studies were initially normal and progress to cerebral hemiatrophia. EEG revealed an absence of correlations between spikes or sharp waves and myoclonic jerks. The morphological investigations and ultrastructural examinations of muscle samples were normal. The activity of NADH-coenzyme Q reductase (complex I) was reduced (inferior to 80% of the normal activity) in the muscle samples of the three patients. No mutation of mtDNA was found in our patients. Two patients died during the year after the admission. Our report establish that EPC can be due to mitochondrial disorders. In the literature, we found three case reports of EPC due to mitochondrial respiratory chain deficiency. In our study, some historical details, clinical findings and initial biological data were indicative for a disorder of mitochondrial metabolism. A previous development delay or extrapyramidal symptoms and others organs involvements in initial presentation should suggest a possible mitochondrial etiology of EPC. Our report emphasizes the importance of studying mitochondrial energy metabolism in patients with EPC