A Case of Myopathy, Encephalopathy, Lactic Acidosis and Stroke-Like Episodes (MEALS) Syndrome with Intracardiac Thrombus
A 27-year-old female was admitted to the hospital because of left hemiplegia and aphasia. She was 162 centimeters tall and 30 kilograms in weight. She was born after a normal pregnancy and delivery. There was no family history of neurological diseases. Motor and intellectual development was normally attained during infancy. She was hospitalized for general muscle weakness and gait disturbance when she was 6 years old. A neurologic exam showed decreased muscle tone and strength, and atrophic muscle mass. She had consistent muscle weakness, so a muscle biopsy was performed from the calf muscle when she was 8 years old. The biopsy showed mitochondrial myopathy of the pleoconial type. Her first echocardiography was completed afterwards and showed marked hypertrophy of both ventricles without any regional wall problems. Follow-up procedures were performed in an outpatient clinic once or twice a year.\nWhen she was 24 years old she had sudden syncope. An magnetic resonance imaging (MRI) revealed acute infarction of the left basal ganglia and the left frontal lobe. Two years later, when the patient was 26, she had another stroke and presented with general weakness, aphagia, and dysarthria. An MRI showed old multifocal infarctions at the basal ganglia, thalamus, left pons and left periventricular white matter area. An MR spectroscopy showed a positive lactate peak in both basal ganglia. These clinical and radiological findings suggested brain involvement of MELAS syndrome. Thus, further evaluation was done for MELAS syndrome including blood lactate and genetic analysis.\nThe plasma lactate level was 21.8 mg/dL (normal range 4.5-19.8 mg/dL). CBC, electrolyte, blood urea nitrogen, and creatinine were in the normal range. Thyroid function was also measured. The free T4 was 1.76 ng/dL (normal range 0.89-1.76 ng/dL) and TSH was 0.04 µIU/mL. Levels of complement component 3 and 4 were 13 mg/dL (normal range 75-145 mg/dL) and 18 mg/dL (normal range 12-72 mg/dL) respectively. Antistreptolysin O antibody was negative, rheumatoid factor was negative, and anti-double stranded DNA was 1.6 (normal range 0-6). Lupus anticoagulants and anti cytoplasmic antibody, which were measured to rule out vasculitis, were normal. A DNA gene sequencing study showed a mutation: m.3303C>T mutation in the mitochondrially encoded tRNA leucine 1 gene, which confirmed the diagnosis of MELAS syndrome. She was treated with supportive care and rehabilitation for a month and was then discharged. Warfarin was used during the hospital stay, but was stopped when she was discharged, because MELAS syndrome causes nonvascular infarct and there is no report about the related risk of thromboembolism.\nOne year later, she presented with another stroke with associated left sided weakness, and was subsequently admitted to the hospital. Her vital signs were stable and there were no specific findings in chest X-rays or electrocardiography. Her MRI revealed infarction in the right middle cerebral territory (). An magnetic resonance angiography showed an occluded right distal internal carotid artery and right middle cerebral artery (). An echocardiography was performed to identify the cardiac origin of the ischemic stroke, and it showed concentrically hypertrophied left ventricle with globally hypokinetic wall motion and ejection fraction of 25%. An intracardiac thrombus attached to the left ventricular apex was noted (). The patient's mental status and general condition improved after she was treated with mannitol and anticoagulation therapy. Rehabilitation and supportive care, including warfarin, were followed and maintained. The patient was discharged after a month.