Subarachnoid haemorrhage of unknown cause: clinical, neuroradiological andevolutive aspects

The clinical and radiological data of 52 patients with subarachnoid haemorr hage (SAH)and a negative panangiography were analysed with an average follo w-up period of 3.8 years. Of these 52 patients, only one (1.9%) was subsequ ently found to have an aneurysm. Second angiography proved to be inconclusi ve in all 24 cases where it was performed. Of the 51 'true' non-aneurysmal SAM, 80% were in a good clinical grade on admission and 12% developed cereb ral ischaemia, The mortality rate following SAH was 4%. There was one reble eding, At follow-up examination, 87% of the patients had made a good recove ry and 6% were left disabled due to SAH, Four patients with an aneurysmal p attern of SAM required a permanent shunt. All of the 22 patients with a per imesencephalic SAH were in a good neurological condition upon admission; on e of them developed an angiography-induced transient cerebral ischaemia and another one suffered from a fatal rebleeding, None of the 21 survivors was disabled at follow-up examination. The clinical course of patients with SA H of unknown cause, especially those with a perimesencephalic pattern of ha emorrhage, is good. Repeated angiography in this latter group is not useful ,In the aneurysmal pattern SAH group, repeat angiography is advised only if there is strong computed tomographic (CT) scan suspicion of an aneurysm.