Osmotic Demyelination Syndrome Presenting with Chorea

Abstract

Osmotic demyelination syndrome is an acute shift in serum osmolality causing demyelination, which may be due to rapid correction of hyponatremia, hyperglycaemia, hypokalemia and ketoacidosis. We present a case of 55yr old female and a known diabetic presented with the choreic movements involving left upper and lower limb for 2 days without any weakness.Her blood sugar was 428mg/dl at the time of admission with wide fluctuations.Her CT Brain showed hyperdensity in the right basal ganglia and the MRI brain showed hyperintense lesion in T2 weighted images showing features suggestive of osmotic demyelination. Patient's sugar levels improved with Insulin and chorea controlled with carbamazepine and sodium valproate. Osmotic demyelination can occur not only due to rapid correction of hyponatremia but also due to wide fluctuations in the blood sugar levels causing swinging of serum osmolarity.