The notion of "warning leaks" in subarachnoid haemorrhage: are such patients in fact admitted with a rebleed?

Objective-Often patients with subarachnoid haemorrhage (SAH) recall a recen t episode of acute severe headache, usually interpreted as a "warning heada che" or first SAH. An alternative explanation is recall bias. The clinical and radiological features of patients with SAH were studied in relation to previous headaches or later rebleeding. Methods-Patients with either a previous headache episode or a subsequent re bleed were selected from the SAH database in Utrecht within 1 month of the index SAH. The clinical condition was graded on the World Federation of Neu rological Surgeons (WFNS) scale. The CT was reviewed and the amounts of sub arachnoid blood, hydrocephalus, and intraventricular, intracerebral, and su bdural blood were rated. Proportions were compared by unpaired or paired t test. Results-Forty four of 390 patients (11%) had had a severe headache before t heir index SAH (11 of these had a subsequent rebleed); 31 other patients ha d a rebleed in hospital but no preceding headache. Patients with and withou t preceding headache did not differ in level of consciousness (14 of 44 v 1 1 of 31 were comatose), nor in any of the radiological features. After rebl eeding (42 patients), 37 of 32 patients were comatose (v 11 of 42 before), and CT showed higher proportions of intracerebral haemorrhage (17%), intrav entricular haemorrhage, (27%), and hydrocephalus (12%) than baseline scans. Intraventricular haemorrhage was twice as frequent after rebleeding than a t baseline. Conclusions-The clinical and radiological features of patients admitted wit h SAH after a preceding bout of headache did not differ from those without such an episode, and are clearly dissimilar from those after documented reb leeds. The findings challenge the existence of minor "warning headaches".