Alcoholic pontine myelinolysis: beware the stroke mimic

Central pontine myelinolysis (CPM), often referred to as osmotic demyelination syndrome, is most commonly seen in the setting of rapid correction of hyponatraemia. Although imaging is the key to diagnosis, conventional CT and MRI findings often lag the clinical manifestations and characteristic MRI changes may be delayed by up to 14 days. We present a case of a 45-year-old female with an extensive history of alcohol misuse and malnutrition who presented with left hemiparesis, initially suspected to be a stroke. This was following a recent hospital admission when she was managed for Wernicke's encephalopathy and treated with electrolyte and vitamin replacement. As part of a "code stroke" protocol, CT was initially performed. The initial non-contrast CT brain and CT angiogram of the intracranial arteries were normal, but a CT brain perfusion study demonstrated increased pontine blood flow. A subsequent MRI of the brain confirmed CPM, which was congruent with her clinical course. This case highlights the importance of osmotic demyelination as a stroke mimic. CPM should be considered in alcoholic patients with neurological impairment regardless of serum sodium. To our knowledge, this is the first published case which illustrates CT perfusion changes in CPM. MRI, however, remains essential for diagnosis.