A clinical and natural history research on mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes

Abstract

Objective To summarize the clinical features, natural history and causes of death of mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS). Methods We retrospectively evaluated the clinical findings of 64 patients diagnosed as MELAS more than 3 years (death cases excluded) in Huashan Hospital from January 2005 to March 2017 and analyzed the natural course and the causes of death of the disease. Results Among 64 patients, the male-to-female ratio was 1.3∶1. Median onset age was 20.5 (16.8) years. The peak of incidence age was from 14 to 22 years. The most common features of MELAS in acute phase were seizures (48/64, 75.0%), headache (41/64, 64.1%), blurred vision (37/64, 57.8%), nausea and vomiting (27/64, 42.1%), fever (25/64, 39.1%), mental and behavioral disorder (24/64, 37.5%). Lactate dehydrogenase (31/60, 51.6%), resting blood lactic acid (43/58, 74.1%) and cerebral spinal fluid lactic acid (9/9) were elevated. Abnormal findings in electroencephalogram (36/40, 90.0%), electrocardiogram (37/47, 78.7%), electromyography (25/41, 61.0%) were detected. In this cohort, 20 patients (20/64, 31.3%) with MELAS were dead. A Kaplan-Meier survival curve showed the estimated overall median survival time was 12 years. The median survival time of the group onset before sex maturity (≤14 years) was 8 years and that in the group onset after sex maturity (>14 years) was 21 years. The causes of death were cardiogenic incidence (4/20, 20.0%), pulmonary infection (4/20, 20.0%), lactic acidosis (2/20, 10.0%) and status epilepticus (2/20, 10.0%). Conclusions MELAS is usually presented in young people associated with high mortality rate. The leading causes of death are cardiogenic, pulmonary infection and lactic acidosis. Key words: MELAS syndrome; Clinical features; Prognosis