Osmotic demyelination syndrome due to rapid fluctuations in serum sodium - a case report

Demyelination of the neural structures can occur due to rapid correction of chronic hyponatremia, and the diagnosis can now be made by radiological demonstration of hyperintense signals on T2 weighted MRI sequences. This is a case report of a 13 year old boy with a craniopharyngioma who underwent a transcranial radical excision of the tumour. Postoperatively he developed diabetes insipidus with a wide fluctuation in the serum sodium levels despite management with intravenous fluids and pitressin analogues. He developed spastic paresis of all 4 limbs with preservation of only vertical eye movements, suggestive of a locked in syndrome. MRI brain showed hyperintense signals within the brainstem and the basal ganglia with no mass effect. A diagnosis of osmotic demyelination was made, and the patient gradually recovered with supportive care over a period of 3 months.