The MRI above belongs to a middle aged man with known chronic alcohol use, who came to the ER with confusion and malaise. His lab work was notable for a serum sodium of 115 mEq/L. He was admitted to the hospital and received a large volume of IV fluids – his sodium the next day was 132 mEq/L. Five days later he returned to the hospital with a spastic gait, dysarthria, and the above brain MRI.
Based on his MRI and symptoms, what condition does he now have? (scroll down for the answer)
- A. Pontine astrocytoma
- B. Osmotic demyelination
- C. Cerebral salt wasting
- D. Brainstem stroke
The answer is B) osmotic demyelination syndrome – in this case, the MRI shows central pontine myelinolysis. Osmotic demyelination can occur anywhere in the brain, although the pons is the most common location.
Common symptoms are spastic gait and dysarthria. Most patients have a serum sodium < 120 mEq/L, which is quickly corrected – a change of 12 mEq/L/day or more can be enough to precipitate osmotic demyelination. Symptoms often develop several days after the sodium correction.
TIP – this syndrome commonly affects patients with hyponatremia who undergo liver transplantation with subsequent sodium normalization.