Pure acute subdural haematoma without subarachnoid haemorrhage caused by rupture of internal carotid artery aneurysm

A 52-year-old female presented with disturbance of consciousness and clinic al signs of tentorial herniation. Computed tomography showed a pure acute s ubdural haematoma (SDH) over the left convexity without subarachnoid haemor rhage. Cerebral angiography showed a saccular aneurysm at the junction of t he left internal carotid artery and the posterior communicating artery. Sur gery to remove the haematoma and clip the aneurysm showed the rupture point was located in the anterior petroclinoid fold (subdural space). The patien t recovered without neurological deficits. Pure SDH caused by ruptured aneu rysm is rare. Rupture of an aneurysm adhered to either the dura or fair and located in the subdural space may cause pure SDH. Therefore, ruptured intr acranial aneurysm should be considered as a cause of non-traumatic SDH. Imm ediate removal of the SDH and aneurysmal clipping is recommended in such pa tients, even those in poor neurological condition.