Acute haemorrhagic leukoencephalitis was first described as a pathological entity by Hurst in 1941.1 It is a rare acute inflammatory myelinopathy of the CNS characterised by progressive loss of consciousness leading to coma accompanied by focal neurological dysfunction. It is now generally accepted that acute haemorrhagic leukoencephalitis is the severe end of the range of acute disseminated encephalomyelitis.2

A 34 year old man presented with rapidly progressive dysphasia, right hemiparesis, and deteriorating level of consciousness over 24 hours after a flu-like illness in the preceding week. He had no history of any other relevant previous illnesses, travel, or immunisation and was not taking any medication.

On initial examination he was febrile at 38°C. He had an expressive dysphasia, was drowsy, and had mild neck stiffness. A right central facial weakness was present and a gag reflex was absent. He moved his left arm and leg to command but only flexed his right arm and leg to …