Cryptococcus neoformans meningitis is confirmed by India ink preparation of CSF showing budding yeast with a wide polysaccharide capsule. Serum cryptococcal antigen (CrAg) lateral flow assay (LFA) returns positive at titre 1:512. What is the most important prognostic marker in this infection?
- A Initial CSF opening pressure on lumbar puncture ✓
- B Serum CrAg titre at diagnosis
- C CD4 count of the HIV-positive patient
- D CSF leucocyte count (pleocytosis)
Explanation
Elevated intracranial pressure (ICP) is the most critical determinant of early mortality in cryptococcal meningitis; opening pressure >25 cmH2O correlates strongly with neurological deterioration and 2-week mortality. WHO 2022 guidelines recommend therapeutic lumbar puncture to reduce opening pressure to ≤20 cmH2O or by 50% if initial pressure was very high, with daily LPs until pressure controlled. CrAg titre reflects fungal burden and predicts response but is secondary to ICP management. Paradoxically, low CSF leucocytosis (poor immune response) also indicates poor prognosis.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.