Best Cases from the AFIP Osmotic Demyelination Syndrome

History A 22-year-old woman with a history of drug abuse was found, by her mother, unconscious and unresponsive at a friend’s house. It was reported that she had a 2-week history of unresponsiveness and vomiting. She was taken to a local hospital by emergency medical services. Upon admission, the patient experienced a generalized tonic-clonic seizure and was intubated for airway protection. She was markedly hyponatremic, her urine toxicology results were negative, and computed tomographic (CT) images of the head were reportedly normal (images unavailable). Her sodium level was rapidly corrected over the course of 11 hours. The initial sodium level was 113 mmol/L. Five hours later it was 124 mmol/L, and 6 hours after that it was 136 mmol/L. For the first few days of hospitalization, the patient remained completely unresponsive. On the 5th day of hospitalization, she began to spontaneously open and close her eyes, but she did not follow commands or track movements. Serial electroencephalograms showed a polymorphic delta rhythm, a finding consistent with severe hypoxic encephalopathy. Magnetic resonance (MR) imaging performed 2 weeks later reportedly showed extensive restricted diffusion throughout the cerebral cortex, thalami, and pons (images unavailable). Her mental status remained unchanged for approximately 2 months, at which time she was transferred to a tertiary care center. Upon admission to the tertiary care center, she was again noted to spontaneously open and close her eyes. Significant findings of neurologic examination were decerebrate posture, bilateral hypertonia in the upper limbs, Babinski reflex on the right side, and normal (downward) plantar reflex on the left.