Central Pontine and Extrapontine Myelinolysis: The Great Masquerader—An Autopsy Case Report

Central pontine myelinolysis is a demyelinating disorder characterized by the loss of myelin in the center of the basis pontis usually caused by rapid correction of chronic hyponatremia. The clinical features vary depending on the extent of involvement. Demyelination can occur outside the pons as well and diagnosis can be challenging if both pontine and extrapontine areas are involved. We herein report a case of myelinolysis involving pons, lateral geniculate bodies, subependymal region, and spinal cord. To the best of our knowledge, this case represents the second case of spinal cord involvement in osmotic demyelination syndrome and the first case of involvement of thoracic region of spinal cord. 1. Introduction Central pontine myelinolysis (CPM) is a demyelinating disorder characterized by the loss of myelin in the center of the basis pontis, usually caused by rapid correction of chronic hyponatremia. On rare occasions, demyelination occurs outside the pons and is termed extrapontine myelinolysis (EPM). The term osmotic demyelination syndrome (ODS) refers to demyelination caused by changes in serum osmolality and may result in both pontine and extrapontine myelinolysis. Known risk factors for this condition include alcoholism, malnutrition, systemic medical disease, liver transplantation, and rarely, hemodialysis [1–3]. We report an unusual case of widespread CPM and EPM affecting the brain and spinal cord in a man with no known risk factor to develop this condition other than fluid resuscitation. 2. Case Report A previously healthy 74-year-old Caucasian male presented to our facility for evaluation of fluctuating mentation, vision loss, and lower extremity weakness of three months duration. Four months prior to admission, he had frequent bouts of nausea and vomiting, resulting in weight loss. Following an episode of severe hematemesis, he received fluid resuscitation and blood transfusion at an outside facility. An esophagogastroduodenoscopy revealed peptic ulcer disease. A few days after his infusion, he became intermittently confused and started complaining of double vision. After a few days, he lost vision in his right eye and became profoundly weak on both legs. His left eye lost vision shortly after. His neurologic examination showed a confused, awake, and elderly man. His vision was limited to light perception in his right eye and finger counting in his left eye. Strength in both lower extremities was 1-2/5. A sensory level to pin prick was noted below the T10 dermatome and vibration and proprioception were intact. He was areflexic and had a