A case of Parkinsonism secondary to Osmotic Demyelination Syndrome

Osmotic demyelination syndrome (ODS) is a rare and potentially treatable cause of secondary parkinsonism. Rapid correction of chronic hyponatremia is the most common culprit. We report a 65-year-old man presenting with parkinsonism and pyramidal tract signs 3 weeks following rapid correction of chronic diuretic induced hyponatremia. His MRI brain revealed typical features of ODS involving pons and bilateral basal ganglia excluding globus pallidi. He was successfully treated with dopaminergic drugs. ODS should be considered as a cause of secondary Parkinson’s disease and the symptoms of ODS can appear as late as 3 weeks after correction of hyponatremia. Chronic hyponatremia should be corrected with great caution in order to prevent ODS especially when there is coexistent hypokalemia.