Does a normal CT scan rule out a subarachnoid haemorrhage?

Abstract

Report by Simon Carley Specialist Registrar Search checked by Paul Wallmann Specialist Registrar A 24 year old man who has been previously well presents to the emergency department complaining of headache. He describes the headache as the worst he has ever had. It came on suddenly approximately two hours previously and has not resolved with paracetamol. It was so severe as to cause him to collapse when it started. He has no other neurological symptoms and clinical examination reveals no neurological signs. You are concerned that he may have had a sub-arachnoid haemorrhage and arrange a CT scan. The …