Morphology: Encapsulated yeast (polysaccharide capsule). India ink stain reveals halo. Mucicarmine and Fontana-Masson positive. Urease-positive.
Typical drugs
- #1Amphotericin B (liposomal)— Induction phase: 3–4 mg/kg/d × 2 wk + flucytosine.
- #2Flucytosine— Induction combo with amphotericin (synergy in CNS disease).
- #3Fluconazole— Consolidation (400–800 mg/d × 8 wk) and chronic suppression (200 mg/d × ≥1 yr in HIV).
Empiric therapy when resistant
Recurrent disease: re-induction with amphotericin + flucytosine, then higher-dose fluconazole consolidation. ID consult.
Resistance mechanisms
Target alteration
Heteroresistance to fluconazole (subpopulations with elevated MICs)
Example: Treatment failure / relapse in chronic suppression.
Resistance notes
Fluconazole heteroresistance recognized. Combination therapy reduces relapse vs monotherapy.
Pearls
Most common in advanced HIV (CD4 <100) and solid organ transplant. Cryptococcal meningitis: HEADACHE, fever, AMS over weeks. Manage opening pressure aggressively (≥25 cm H2O → drain to <20 or 50% of opening). IRIS in HIV — delay ART start by 4–6 weeks after antifungal start. C. gattii (var. grubii / Pacific Northwest) more virulent in immunocompetent hosts.
References
- IDSA Cryptococcus Guidelines (2010)
- WHO HIV Cryptococcal Disease Guidelines (2022)