Hyponatraemic encephalopathy: an unusual stroke mimic.

We present a case of a 74-year-old man who was admitted to our stroke unit with symptoms and signs suggestive of a left total anterior circulation stroke. Subsequent MRI failed to support this diagnosis and, furthermore, correction of an incidental finding of hyponatraemia due to syndrome of inappropriate antidiuretic hormone secretion led to a complete recovery of symptoms. Investigation and subsequent exclusion of other potential differential diagnoses confirmed the diagnosis of hyponatraemia mimicking acute stroke.