North American Journal of Medical Sciences

: 2013  |  Volume : 5  |  Issue : 8  |  Page : 492--493

Central nervous system and Cryptococcus neoformans

Veronica A Gaona-Flores 
 Infectology Hospital, National Medical Center "La Raza" Instituto Mexicano del Seguro Social, Mxico, D.F., Mexico

Correspondence Address:
Veronica A Gaona-Flores
Infectology Hospital CMN DQLa RazaDQ

How to cite this article:
Gaona-Flores VA. Central nervous system and Cryptococcus neoformans.North Am J Med Sci 2013;5:492-493

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Gaona-Flores VA. Central nervous system and Cryptococcus neoformans. North Am J Med Sci [serial online] 2013 [cited 2023 Feb 4 ];5:492-493
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Cryptococcus neoformans continues to be an important cause of morbidity and mortality, and is the most common central nervous system (CNS) mycosis in immunocompromised patients, in particular those with AIDS. C. neoformans has also increased in immunocompromised transplant patients, [1],[2],[3],[4] and is a systemic mycosis. The incidence of infection due to C. neoformans varies among continents.

C. neoformans is a form of yeast with biochemical, antigenic, and epidemiological differences. There are two known varieties. Most infections are due to C. neoformans var. grubii and a lesser number due to C. gattii (Africa, Australia, Canada, Latin America). Clinical presentations also depend on the characteristics of the immunological competency of the patients. In general, it is a systemic fungal infection with its origin as the inhalation of C. neoformans, initially affecting the lungs. Therefore, CNS manifestations are as a result of the dissemination of this fungus from the lung. [5]

The polysaccharide capsule of C. neoformans is the most potent virulence factor, which also allows it to evade the immune system. Laboratory diagnosis is accomplished either by ELISA or latex agglutination test, or visualization of the capsule upon direct examination of fresh cerebrospinal fluid (CSF), in particular with China ink (India ink staining or nigrosine allows for the identification of the yeast from 4-20 mm in diameter). With this negative stain, identification of the image of the capsule and yeast in the center will be possible. When the fungal burden is high, the pseudomycelium may be observed most of the time. On other occasions it is practical to centrifuge the CSF at 3,000 rpm Χ 10 min. The sediment is useful for microscopic study and cultures. Another accessible study is latex agglutination, which identifies the A, B, C, and D serotypes that constitute the C. neoformans/C. gattii complex.

Clinical correlation and suspicion of the infection are important. As in all laboratory tests, there are false negatives and false positives, thereby the importance of obtaining the CSF culture, which allows identification of the yeasts of C. neoformans. Genotypic identification proposed by the genotyping working group of C. neoformans and C. gattii selected multilocus sequence typing (MLST), which identifies structural genes. [6]

Treatment has been established, [7] however, we must pay close attention not only to the diagnosis and treatment, but also to the cryptococcal immune reconstitution inflammatory syndrome (IRIS) that may present itself as clinical deterioration or as a new or recurrent presentation of cryptococcal disease after initiation of antiretroviral therapy (ART), despite microbiological evidence of effective antifungal treatment. [8],[9]


1McCarthy KM, Morgan J, Wannemuehler KA, Mirza SA, Gould SM, Mhlongo N, et al. Population based surveillance for cryptococcosis in an antiretroviral-naive south African province with a high HIV seroprevalence. AIDS 2006;20:2199-206.
2Luma HN, Temfack E, Halle MP, Tchaleu BCN, Mapoure YN, Koulla-Shiro S. Cryptococcal meningoencephalitis in human immunodeficiency Virus/Acquired Immunodeficiency Syndrome in douala, cameroon: A cross sectional Study. N Am J Med Sci 2013;5:486-91.
3Silveira FP, Husain S, Kwak EJ, Linden PK, Marcos A, Shapiro R, et al. Cryptococcosis in liver and kidney transplant recipients receiving anti-thymocyte globulin or alemtuzumab. Transpl Infect Dis 2007;9:22-7.
4Wu G, Vilchez RA, Eidelman B, Fung J, Kormos R, Kusne S. Cryptococcal meningitis an analysis among 5,521 consecutive organ transplant recipients. Transpl Infect Dis 2002;4:183-8.
5Mitchel TG, Litvintseva AP. Typing species of cryptococcus and epidemiology of cryptococcosis. In: Ashbee R, Bignell EM, Editors. Pathogenic Yeast. The Yeast Handbook. Berlin: Springer; 2010. p. 167-90.
6Huston SM, Mody CH. Cryptococcosis: An emerging respiratory mycosis. Clin Chest Med 2009;30:253-64.
7Perfect JR, Dismukes WE, Dromer F, Goldman DL, Graybill JR, Hamill RJ, et al. Clinical practice guidelines for the management of cryptococcal disease: 2010 update by the Infectious Diseases Society of America. Clin Infect Dis 2010;50:291-322.
8Boulware DR, Bonham SC, Meya DB, Wiesner DL, Park GS, Kambugu A, et al. Paucity of initial cerebrospinal fluid inflammation in cryptococcal meningitis is associated with subsequent immune reconstitution inflammatory syndrome. J Infect Dis 2010;202:962-70.
9Bicanic T, Meintjes G, Rebe K, Williams A, Loyse A, Wood R, et al. Immune reconstitution inflammatory syndrome in HIV associated cryptococcal meningitis: A prospective study. J Acquir Immune Defic Syndr 2009;51:130-4.