A 55-year-old woman with a ruptured anterior communicating artery aneurysm (Hunt-Hess grade III, Fisher grade 3) undergoes successful surgical clipping on day 1. On day 7, she develops fever, nuchal rigidity, and persistent neurological deterioration despite nimodipine. CSF analysis shows WBC 800/cumm (90% neutrophils), protein 120 mg/dL, glucose 25 mg/dL (blood glucose 110 mg/dL). What is the most likely cause of her deterioration?

• A Rebleeding from the clipped aneurysm
• B Hydrocephalus
• C Cerebral vasospasm
• D Bacterial meningitis ✓

Explanation

Post-craniotomy fever with neutrophilic pleocytosis, markedly elevated protein, and low CSF glucose (CSF:blood glucose ratio <0.4) is diagnostic of bacterial meningitis, a known complication of craniotomy and external ventricular drain placement. Rebleeding would show fresh blood on CT without CSF pleocytosis. Vasospasm causes focal deficits without fever or CSF pleocytosis. Hydrocephalus develops gradually with gait disturbance and enlarged ventricles on CT (Greenberg, 9th ed.; Harrison, 20th ed.).

Reference: Greenberg's Handbook of Neurosurgery, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.