Central Pontine Myelinolysis
A 35-year-old man presented with acute alcoholic hepatitis and encephalopathy. He was hyponatremic, with a sodium level of 119 mmol per liter. Over the next 5 days his clinical condition improved with supportive treatment, which included lactulose and intravenous vitamins and the careful administration of normal saline for hypovolemia. His serum sodium level gradually increased by approximately 3 mmol per liter per day until reaching 135 mmol per liter. On the sixth day, his level of consciousness declined to a score of 6 on the Glasgow Coma Scale (a scale of 3 to 15, with lower scores indicating reduced levels of consciousness). Findings on computed tomography of the head, performed without the administration of contrast material, were unremarkable. Over the next 2 days, neurologic examination revealed tetraparesis with normal tone. The quadriceps and biceps reflexes were brisk, and the plantar reflex was upward in both feet, but other reflexes were normal. Magnetic resonance imaging of the brain revealed a central area of high T2 (Panel A, arrows) and low T1 (Panel B, arrow) signaling in the pons, with restricted diffusion (Panel C, arrows). These findings are typical in patients with central pontine myelinolysis, or osmotic demyelination syndrome, which typically occurs in response to overly rapid correction of hyponatremia (usually a correction of more than 9 mmol per liter per 24 hours). Clinical features can range from confusion and drowsiness to dysphagia, dysarthria, varying degrees of paresis, and coma or locked-in syndrome. Alcoholism and liver disease predispose patients to central pontine myelinolysis. Our patient subsequently regained the use of his arms and legs slowly over the course of the next year, but bulbar palsy persisted, necessitating permanent placement of a gastrostomy tube for feeding.
