Corticosteroid treatment of mitochondrial encephalomyopathies

BACKGROUND- Mitochondrial encephalopathy with lactic acidosis and stroke-like symptoms (MELAS) is a multisystem disorder characterized by stroke-like episodes, seizures, dementia, headaches, and evidence of mitochondrial myopathy. Lactic acidosis and ragged red fibers are often present. A variety of therapies have been used with inconclusive and disappointing results. There have been very few cases of MELAS reported as corticosteroid responsive. SUMMARY- A 27-year-old healthy man was hospitalized with recurrent generalized tonic-clonic seizures, intractable headaches, and stroke-like symptoms. These symptoms improved after the initiation of corticosteroid treatment. Multiple attempts to taper corticosteroids were followed by clinical relapse. Genetic testing in this patient revealed a point mutation at nt 3243 of the mitochondrial tRNA gene, confirming the diagnosis of MELAS. The patient died 1 year later after an episode of status epilepticus. Corticosteroid therapy in individual MELAS patients has been associated with clinical improvement. Discrepancy exists with regard to corticosteroid type, dose, route of administration, length of therapy, patient population, and clinical and metabolic parameters to follow during corticosteroid therapy. CONCLUSIONS- Corticosteroid therapy may be beneficial during acute exacerbation of MELAS.