July 17, 2014
A 36-year-old woman with abrupt onset of hearing loss, left-sided weakness, and seizures
Mitochondrial Encephalopathy Lactic Acidosis Stroke-Like Episodes (MELAS)
- MELAS is characterized by stroke-like events that are acute in onset, often transient.
- Generally presents between the ages of 3 months and 40 years. Seizures, nausea/vomiting, headaches, and hearing loss are common symptoms.
- Linked to mutations in mitochondrial DNA inherited from the mother.
- Key Diagnostic Features: Hyperintense T2 lesions, predominately in the gray and subcortical white matter in the temporal, parietal, and occipital lobes. Frontal lobes are not commonly involved. Lesions generally spare the deep white matter and may cross vascular boundaries. Basal ganglia calcification is often seen (better appreciated on CT – interval progression of calcification is suggestive of MELAS). Follow-up MRI studies may show lesion resolution, sometimes with interval appearance of new lesions.
- DDx: Ischemic stroke, Kearns-Sayre syndrome, Leigh syndrome, Pearson syndrome
- Rx: Aimed at increasing the production of ATP. Coenzyme CoQ10 has been helpful to some patients. Other therapies include carnitine, riboflavin, ascorbic acid, and L-arginine.
