- Major invasive fungal infection, caused by encapsulated yeasts
- There are >30 different species of Cryptococcus. Two species cause nearly all cryptococcal disease in humans—Cryptococcus neoformans and Cryptococcus gattii. C. neoformans is the principal human pathogen:
- C. neoformans infection is more common in immunocompromised persons.
- Two varieties: C. neoformans var. grubii, C. neoformans var. neoformans
- C. gattii causes disease in otherwise healthy persons (1).
- Cryptococcus is found in the droppings of wild birds, often pigeons. Dust from the droppings (soil or vegetation) can infect humans (or pets) by inhalation.
- Infected humans and animals are not infectious.
- Primary route of infection is inhalation of spores, followed by hematogenous spread.
- Predisposition for nervous system and skin
- Can remain latent in the lungs for varying periods
- Cryptococcal meningitis is a common AIDS-defining infection in HIV-seropositive persons.
- Predominant group: immunosuppressed adults, with CD4 cell counts below 100 cells/μL
- Predominant gender: male > female (reflecting HIV prevalence)
- Major disease burden in sub-Saharan Africa followed by South and Southeast Asia, Oceania, Western and Central Europe. North Africa, Middle East, and North America have the fewest cases (1,2).
- Incidence decreasing in developed nations due to highly active antiretroviral therapy (HAART) for HIV:
- 1 million new cases worldwide each year
- 600,000 deaths worldwide each year mostly in sub-Saharan Africa (500,000)
- 2–7% of opportunistic infections in AIDS patients in the United States with fatality rate of 12%
- 0.5–1% incidence among HIV-infected children in United States
- 0.4 to 1.3 cases per 100,000 in general population (1,3)
- U.S. AIDS patients: 3%
- AIDS patients in developing world: up to 38%
- U.S. organ transplantation recipients: 3%
- Common in renal transplant patients
- Can be seen in extrathoracic sarcoidosis
Etiology and Pathophysiology
- Cryptococcus is found in pigeon droppings; transmission likely through exposure to contaminated soil or vegetation rather than direct exposure
- Virulence factors: polysaccharide capsule and capacity for biofilm formation. Unencapsulated forms are readily phagocytosed. Polysaccharide capsule resists phagocytosis and inhibits leukocyte migration to areas of fungal replication.
- Immunosuppression due to HIV (CD4 <100 cells/mm3)
- Immunosuppression from chronic steroid use or other medications (biologic agents)
- Organ transplant, malignancy, or sarcoidosis
- Early HAART in HIV-positive patients is the most important and cost-effective preventive strategy.
Commonly Associated Conditions
There's more to see -- the rest of this topic is available only to subscribers.
Domino, Frank J., et al., editors. "Cryptococcosis." 5-Minute Clinical Consult, 27th ed., Wolters Kluwer, 2020. Medicine Central, im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688739/all/Cryptococcosis.
Cryptococcosis. In: Domino FJF, Baldor RAR, Golding JJ, et al, eds. 5-Minute Clinical Consult. Wolters Kluwer; 2020. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688739/all/Cryptococcosis. Accessed May 29, 2023.
Cryptococcosis. (2020). In Domino, F. J., Baldor, R. A., Golding, J., & Stephens, M. B. (Eds.), 5-Minute Clinical Consult (27th ed.). Wolters Kluwer. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688739/all/Cryptococcosis
Cryptococcosis [Internet]. In: Domino FJF, Baldor RAR, Golding JJ, Stephens MBM, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2020. [cited 2023 May 29]. Available from: https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688739/all/Cryptococcosis.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Cryptococcosis ID - 1688739 ED - Domino,Frank J, ED - Baldor,Robert A, ED - Golding,Jeremy, ED - Stephens,Mark B, BT - 5-Minute Clinical Consult, Updating UR - https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688739/all/Cryptococcosis PB - Wolters Kluwer ET - 27 DB - Medicine Central DP - Unbound Medicine ER -