Cryptococcosis is a fungal infection caused by Cryptococcus neoformans, a globally distributed fungus that is commonly found in soil, especially that containing pigeon and avian droppings. Infection is acquired by inhaling spores of fungus.
Occurs worldwide without any defined endemic areas. Cryptococcal infections in humans likely occur when the organism is aerosolised and inhaled 3.
The lungs, central nervous system, blood, skin, bone, joints, and prostate are the most commonly involved sites.
It occurs predominantly in immunocompromised patients but can also be seen in the normal host 1:
- immunocompetent host: cryptococcal infections are commonly localised to the lung and the patients are asymptomatic
- immunocompromised patient: cryptococcal infections often cause symptomatic pulmonary infections and then often disseminate to the central nervous system, skin, and bones
In fact, central nervous system infection after haematogenous dissemination is more common than pulmonary infection.
Serum cryptococcal antigen is helpful in diagnosis and follow-up of pulmonary and systemic disease. Antigen titers correspond to severity of illness. In CNS cryptococcosis, lumbar puncture is very helpful and shows increased CSF pressure, decreased glucose, increased protein, and mild to moderate leucocytosis. Indian ink test is highly specific and colours the thick round capsule of the yeast.
- 1. Müller NL, Franquet T, Lee KS et-al. Imaging of pulmonary infections. (2007) ISBN:078177232X. Read it at Google Books - Find it at Amazon
- 2. Lindell RM, Hartman TE, Nadrous HF et-al. Pulmonary cryptococcosis: CT findings in immunocompetent patients. Radiology. 2005;236 (1): 326-31. doi:10.1148/radiol.2361040460 - Pubmed citation
- 3. Nadrous HF, Antonios VS, Terrell CL et-al. Pulmonary cryptococcosis in nonimmunocompromised patients. Chest. 2003;124 (6): 2143-7. Chest (citation) - Pubmed citation