Pituitary apoplexy can mimic subarachnoid haemorrhage clinically and radiologically.

Pituitary apoplexy is when there is acute haemorrhage into a pituitary adenoma. It presents with headache and altered consciousness with loss of pituitary function. Many cases have bitemporal hemianopia. Subarachnoid haemorrhage is in the differential diagnosis, but does not cause a similar visual field defect. Magnetic resonance imaging is required to diagnose the pituitary tumour. An elderly man who presented with acute headache, and who was initially diagnosed with subarachnoid haemorrhage but re-presented with features of pituitary apoplexy, is described.