The osmotic demyelinating syndromes are not always restricted to the pons. The extrapontine myelinolysis is seen in 10% of patients with central pontine myelinolysis. We present a 62-year-old woman who developed hyponatremia due to repeated vomiting. An acute akinetic-rigid syndrome followed rapid correction of hyponatremia. Bilateral putaminal and caudate lesions were seen on MRI. There were no clinical features of pontine involvement even though a typical lesion was seen on MRI. She recovered well with only symptomatic treatment. Although the exact pathogenesis is unknown, the most widely accepted hypothesis is that cellular edema secondary to the fluctuating osmotic forces, with rapid correction of hyponatremia, results in fibre-tract compression and demyelination. In contrast to the generally expected poor outcome in this condition, patients do have good recovery with symptomatic treatment and good nursing care.
