An 8-year-old who recovered from tuberculous meningitis 6 months ago now has papilledema and enlarged ventricles on imaging. CSF opening pressure is raised, but there is no intraventricular obstruction, and contrast studies show CSF flowing freely from the ventricles to the subarachnoid space. What is the mechanism of this hydrocephalus?
- A Impaired absorption of CSF at the arachnoid granulations ✓
- B Obstruction of the aqueduct of Sylvius
- C Overproduction of CSF by choroid plexus papilloma
- D Obstruction at the foramen of Monro
Correct answer: A. Impaired absorption of CSF at the arachnoid granulations
Explanation
Post-infectious hydrocephalus after meningitis is typically communicating: basal adhesions and thickened arachnoid impair CSF resorption across the arachnoid villi and granulations into the venous sinuses, so ventricles enlarge despite free internal flow. Aqueductal stenosis and foramen of Monro obstruction are non-communicating (obstructive) forms in which the blockage lies within the ventricular system itself. Choroid plexus papilloma causes hydrocephalus by overproduction but is rare and would show a mass lesion on imaging.
Reference: Nelson Textbook of Pediatrics, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.