A 30-year-old HIV-positive man with CD4 count of 80 cells/µL presents with altered sensorium, fever, and headache. CSF India ink preparation shows encapsulated yeast cells with a thick polysaccharide capsule. The responsible organism typically enters the CNS via which route?

• A Direct inoculation through skull fracture
• B Retrograde spread along olfactory nerve fibers
• C Reactivation of latent viral infection in trigeminal ganglion
• D Hematogenous spread from primary pulmonary infection ✓

Explanation

Cryptococcus neoformans causes cryptococcal meningoencephalitis predominantly in immunocompromised patients. The organism is inhaled from the environment (pigeon droppings) and establishes a primary pulmonary infection, from which it disseminates hematogenously to the CNS. The thick polysaccharide capsule impairs complement fixation and phagocytosis, enabling CNS invasion. The India ink preparation demonstrates the capsule as a clear halo around the budding yeast against a dark background.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.