Extrapontine myelinolysis with parkinsonism after rapid correction of hyponatremia: high cerebrospinal fluid level of homovanillic acid and successful dopaminergic treatment.

Extrapontine myelinolysis (EPM) is a demyelinating process of the brain. We report the case of an 11-year-old girl who developed EPM with parkinsonism. Magnetic resonance imaging revealed demyelinating patterns in the basal ganglia without central pontine lesions. The cerebrospinal fluid levels of homovanillic acid and 5-hydroxyindoleacetic acid were high at the time of onset and normalized upon complete recovery from extrapyramidal symptoms after a dopaminergic treatment. We speculated that demyelination of nerve fibers containing dopamine receptors in the striatum might be a main cause of these symptoms.