Extent of acute hydrocephalus after subarachnoid hemorrhage as a risk factor for poor functional outcome

Objectives: To evaluate the correlation between acute hydrocephalus after subarachnoid hemorrhage (SAH) and functional outcome 1 year after the event. Methods: We retrospectively reviewed the clinical and radiological information on consecutive adult patients admitted to our hospital with a diagnosis of acute SAH between 1 January 2002 and 1 January 2008. Patients with early death of any cause, chronic hydrocephalus, or evidence of radiological infarction were excluded. Remaining patients were grouped based on the presence or absence of acute hydrocephalus. The extent of ventricular dilatation was expressed as a function of bicaudate distance. Functional outcomes at 1 year after the hemorrhage were compared between patients with and without acute hydrocephalus. Results: We included 110 patients of whom 57 (52%) had acute hydrocephalus. Acute hydrocephalus was an independent risk factor for poor functional outcome in multivariate analysis (P=0.006). Patients were categorized into quartiles based on the relative bicaudate index (RBCI). The proportion of patients with poor functional outcome increased in consecutive quartiles (P=0.0001). The adjusted odds ratio for the highest quartile of RBCI versus the lowest was 7.2 (95% confidence interval: 2.1-25.2). Initiation of treatment at or above an RBCI value of 1.6 (+/- 0.3) did not significantly improve functional outcome (P=0.15). Conclusion: The extent of ventricular dilatation after SAH is a strong risk factor for development of poor functional outcome in the year following the event. The proportion of patients with poor outcome was not significantly different with and without cerebrospinal fluid drainage, when treatment was initiated at an RBCI of >= 1.6. Our results suggest that development of acute hydrocephalus after SAH adversely affects long-term functional outcome. Moreover, cerebrospinal fluid flow diversion strategies might best be aimed at preventing ventricular enlargement rather than at treating an established hydrocephalus.