Delayed and extra-pontine myelinolysis after osmotic dysregulation.

1 Division of Neurology, National University Hospital, Singapore Address for Correspondence: Dr Vijay Sharma, Division of Neurology, Department of Medicine, National University Hospital, Singapore 119074. Email: [email protected] A 58-year-old Chinese man was admitted because of increasing lethargy and confusion over 4 days. He had been taking hydrochlorthiazide for hypertension and regularly consumed ethanol in moderation. Examination showed a conscious, well-hydrated man with slow verbal responses and unstable gait. Laboratory tests suggested hyponatremia due to the syndrome of inappropriate secretion of antidiuretic hormone (serum sodium 104 mmol/L, urine sodium 25 mmol/L, serum osmolality 213 mosm/kg and urine osmolality 439 mosm/kg). Thyroid function tests, computed tomographic (CT) scan of the brain, and chest X-ray were unremarkable. With intravenous thiamine and fluid