title: Misdiagnosis of symptomatic cerebral aneurysm. Prevalence and correlation with outcome at four institutions.
abstract: OBJECTIVE
  It is not known what fraction of patients with symptomatic cerebral aneurysms are misdiagnosed at initial medical presentation. It is also not clear whether misdiagnosed patients more frequently 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 according to misdiagnosis or correct diagnosis at initial medical evaluation.
  
  
  RESULTS
  Fifty-four of 217 patients (25%) were misdiagnosed at initial medical evaluation, including 46 of 121 patients (38%) initially 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 compared with 75 of 163 patients (46%) with correct initial diagnosis (P < .01). Twenty-six of 54 misdiagnosed patients (48%) deteriorated or rebled before definitive aneurysm treatment compared with 4 of 165 correctly diagnosed patients (2%) (P < .001). Among patients initially presenting as clinical grade 1 or 2, overall good or excellent outcome was achieved in 91% of those with correct initial diagnosis and 53% of patients with initial misdiagnosis (P < .001). Deterioration before correct diagnosis accounted for 16 of 67 patients (24%) with poor or worse final outcome in this series.
  
  
  CONCLUSIONS
  Patients in good clinical condition with symptomatic cerebral aneurysms were commonly misdiagnosed. Misdiagnosed patients were more likely than correctly diagnosed patients to deteriorate clinically and had a worse overall outcome. Misdiagnosed cases accounted for a significant fraction of overall poor outcomes among consecutive cases of symptomatic aneurysms.
authors.affiliation: Neurovascular Surgery Program, Yale University School of Medicine, New Haven, Conn 06520, USA.
authors.forename: P L
authors.initials: PL
authors.lastname: Mayer
authors.forename: I A
authors.initials: IA
authors.lastname: Awad
authors.forename: R
authors.initials: R
authors.lastname: Todor
authors.forename: K
authors.initials: K
authors.lastname: Harbaugh
authors.forename: G
authors.initials: G
authors.lastname: Varnavas
authors.forename: T A
authors.initials: TA
authors.lastname: Lansen
authors.forename: P
authors.initials: P
authors.lastname: Dickey
authors.forename: R
authors.initials: R
authors.lastname: Harbaugh
authors.forename: L N
authors.initials: LN
authors.lastname: Hopkins
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D015995:Prevalence; D012008:Recurrence; D012189:Retrospective Studies; D013345:Subarachnoid Hemorrhage / Q000209:etiology