MISDIAGNOSIS OF SYMPTOMATIC CEREBRAL ANEURYSM - PREVALENCE AND CORRELATION WITH OUTCOME AT 4 INSTITUTIONS

Background and Purpose It is not known what fraction of patients with symptomatic cerebral aneurysms are misdiagnosed at initial medical pre sentation. It is also not clear whether mis-diagnosed patients more fr equently deteriorate before definitive aneurysm diagnosis and therapy or achieve a poorer outcome than correctly diagnosed patients. Methods We reviewed records of consecutive patients with symptomatic cerebral aneurysms managed by four tertiary-care neurosurgical services during a recent 19-month period. Clinical course and outcome were analyzed a ccording to misdiagnosis or correct diagnosis at initial medical evalu ation. Results Fifty-four of 217 patients (25%) were misdiagnosed at i nitial medical evaluation, including 46 of 121 patients (38%) initiall y in good clinical condition (clinical grade 1 or 2). Forty-six of 54 patients (85%) in the misdiagnosis group were initially grade 1 or 2 c ompared with 75 of 163 patients (46%) with correct initial diagnosis ( P<.01). Twenty-six of 54 misdiagnosed patients (48%) deteriorated or r ebled before definitive aneurysm treatment compared with 4 of 165 corr ectly diagnosed patients (2%) (P<.001). Among patients initially prese nting as clinical grade 1 or 2, overall good or excellent outcome was achieved in 91% of those with correct initial diagnosis and 53% of pat ients with initial misdiagnosis (P<.001). Deterioration before correct diagnosis accounted for 16 of 67 patients (24%) with poor or worse fi nal outcome in this series. Conclusions Patients in good clinical cond ition with symptomatic cerebral aneurysms were commonly misdiagnosed. Mis-diagnosed patients were more likely than correctly diagnosed patie nts to deteriorate clinically and had a worse overall outcome. Misdiag nosed cases accounted for a significant fraction of overall poor outco mes among consecutive cases of symptomatic aneurysms.