RESUMEN
In a series of 441 patients with signs and symptoms of spontaneous subarachnoid haemorrhage (SAH) in 62 subjects haemorrhagic aetiology could not be established. All patients were admitted during the first week of haemorrhage (most of them within 72 hours). The majority belonged to Hunt's and Hess' 1 and 2 degrees of bleeding (80.64%). Blood in subarachnoid region could not be verified by CT in 30.03% of patients. Among patients with manifested haemorrhages in 59% haemorrhage was localized in perimencephalic cisternae, and in the others a kind of SAH with characteristics of aneurysmal rupture was observed. Digital substratum angiography (DSA) of four cerebral blood vessels was performed in all patients; in 17 patients the procedure had to be repeated, but without a new pathologic substrate. The recovery of the majority of patients (91.93%) was good, and only one patient died one year after the insult. The patients with aneurysmal SAH were separately treated. In these patients the recovery was noted in 73.33% of subjects, and the rest manifested a mild invalidity. In general, patients with SAH of unknown aetiology have a better prognosis than those with aneurysmal SAH.