Incidence, Timing, and Predictors of Delayed Shunting for Hydrocephalus After Aneurysmal Subarachnoid Hemorrhage.

BACKGROUND: Although hydrocephalus is often treated with permanent cerebrospinal fluid (CSF) shunting during hospitalization for acute aneurysmal subarachnoid hemorrhage (SAH), little is known about the development of delayed hydrocephalus.
METHODS: Using administrative data on all visits to nonfederal emergency departments and acute care hospitals across California from 2005 to 2010, we identified patients with SAH and discharged without placement of a CSF shunt. Patients were followed for up to 7 years to determine whether they subsequently developed delayed hydrocephalus, as indicated by hospitalization for a permanent CSF diversion procedure.
RESULTS: In 8,889 patients discharged with SAH, 116 (1.3 %) went on to develop delayed hydrocephalus. Most (>90 %) diagnoses of delayed hydrocephalus occurred within the first year after discharge. Cox proportional hazards analysis identified microsurgical clipping (hazard ratio 2.0; 95 % confidence interval 1.2-3.3), temporary ventriculostomy placement (2.5; 1.6-4.1), mechanical ventilation (1.7; 1.1-2.8), and discharge to a skilled nursing facility (2.9; 1.8-4.6) as being significantly associated with the development of delayed hydrocephalus. At 1 year after discharge, the cumulative rate of delayed hydrocephalus was 0.9 % (95 % CI, 0.7-1.1 %) for those without temporary ventriculostomy placement during the initial hospitalization, versus 5.7 % (95 % CI, 3.9-8.1 %) in those who had received a temporary ventriculostomy.
CONCLUSION: Delayed hydrocephalus after SAH occurs rarely overall, but in a substantial proportion of patients who required temporary ventriculostomy during the initial hospitalization. These results support vigilant surveillance of patients after removal of a temporary ventriculostomy, given the potential of delayed hydrocephalus to impair recovery or even result in clinical deterioration following SAH.