Central pontine myelinolysis in a normonatremic patient with depression

A 76-year-old male presented with a recurrent depressive episode, an unsteady gait and cognitive impairment. Extensive blood tests, including hemogram, biochemical tests, folic acid, vitamin B12, and thyroid hormone, showed normal results. With the exception of the unsteady gait, neurological examination was negative. Brian magnetic resonance imaging (MRI) showed the typical feature of central pontine myelinolysis (CPM); however, there was no history of alcoholism, liver transplantation, malnutrition or rapid correction of hyponatremia. The patient had taken venlafaxine to treat major depressive disorder for more than 20 years. After discontinuation of venlafaxine, the unsteady gait gradually resolved, and subsequent MRI revealed reduction of the lesions over 6 months. We discuss herein the possible correlation between chronic use of venlafaxine and CPM.