Cryptococcosis


Cryptococcosis
Cryptococcosis
Classification and external resources

Histopathological image of pulmonary cryptococcosis in an immunocompromised host. Alcian blue-PAS stain.
ICD-10 B45
ICD-9 117.5
DiseasesDB 3213
eMedicine med/482
MeSH D003453

Cryptococcosis, or cryptococcal disease, is a potentially fatal fungal disease. It is caused by one of two species; Cryptococcus neoformans and Cryptococcus gattii. These were all previously thought to be subspecies of C. neoformans, but have now been identified as distinct species.

Cryptococcosis is believed to be acquired by inhalation of the infectious propagule from the environment. Although the exact nature of the infectious propagule is unknown, the leading hypothesis is the basidiospore created through sexual or asexual reproduction.

Contents

Etiology and Incidence

Cryptococcosis is a defining opportunistic infection for AIDS. Other conditions which pose an increased risk include certain lymphomas (e.g. Hodgkin's lymphoma), sarcoidosis, and patients on long-term corticosteroid therapy.

Distribution is worldwide in soil[1]. The prevalence of cryptococcosis has been increasing over the past 20 years for many reasons, including the increase in incidence of AIDS and the expanded use of immunosuppressive drugs.

In humans, C. neoformans causes three types of infections:

  • Wound or cutaneous cryptococcosis
  • Pulmonary cryptococcosis, and
  • Cryptococcal meningitis.

Cryptococcal meningitis (infection of the meninges, the tissue covering the brain) is believed to result from dissemination of the fungus from either an observed or unappreciated pulmonary infection. Cryptococcus gattii causes infections in immunocompetent people (those having a functioning immune system), but C. neoformans v. grubii, and v. neoformans usually only cause clinically evident infections in persons who have some form of defect in their immune systems (immunocompromised persons). People who have defects in their cell-mediated immunity, for example, people with AIDS, are especially susceptible to disseminated cryptococcosis. Cryptococcosis is often fatal, especially if untreated.

Although the most common presentation of cryptococcosis is of C. neoformans infection in an immunocompromised person (such as patients with AIDS), the C. gattii is being increasingly recognised as a pathogen in presumptively immunocompetent hosts, especially in Canada and Australia. This may be due to rare exposure and high pathogenicity, or to unrecognised isolated defects in immunity specific to this organism.

Diagnosis

Symptoms include fever, fatigue, chest pain, dry cough, swelling of abdomen, headache, blurred vision and confusion.[2]

Detection of cryptococcal antigen (capsular material) by culture of CSF, sputum and urine provides definitive diagnosis. Blood cultures may be positive in heavy infections.

Cryptococcosis can rarely occur in the immunocompetent person without HIV, when it usually goes undiagnosed. Less than 250 cases in all are reported in the medical literature, the majority diagnosed postmortem.[3]

Treatment

Treatment options in non-AIDS patients who have reduced immune-system function is not well studied. Intravenous Amphotericin B combined with oral flucytosine may be effective. Every attempt should be made to reduce the amount of immunosuppressive medication until the infection is resolved.

AIDS patients often have a reduced response to Amphotericin B and flucytosine, therefore after initial treatment as above, oral fluconazole can be used.[2] The decision on when to start treatment for HIV is not yet settled, although one small, under-powered trial suggested that delaying the start of treatment for 10 weeks may be beneficial in avoiding deaths from Immune reconstitution inflammatory syndrome (IRIS).[4]

IRIS in immunocompetent hosts

The immune reconstitution inflammatory syndrome (IRIS) has been described in immunocompetent hosts who have meningitis caused by C. gattii and C. grubii. Several weeks or even months into appropriate treatment, there is a sudden onset deterioration with worsening meningitis symptoms and progression or development of new neurological symptoms.

Magnetic resonance imaging shows increase in the size of brain lesions, and CSF abnormalities (white cell count, protein, glucose) increase. CSF culture is sterile, and there is no increase in CSF cryptococcal antigen titre.

The increasing inflammation can cause brain injury or be fatal.[5] [6] [7]

The mechanism behind IRIS in cryptococcal meningitis may be local or systemic immunosuppression induced by the cryptococcal infection which resolves as the organism is killed by antifungal treatment. This is associated with increased inflammation as the recovering immune system recognises the fungus. Treatment with systemic corticosteroids during IRIS may be beneficial in preventing death or progressive neurological deterioration.

IRIS may be the cause of paradoxically worse outcomes for cryptococcal meningitis in immunocompetent compared with immunocompromised hosts, in whom Cryptococcus neoformans is the usual pathogen.

Veterinary cases

Cryptococcosis is also seen in cats and occasionally dogs. It is the most common deep fungal disease in cats, usually leading to chronic infection of the nose and sinuses, and skin ulcers. Cats may develop a bump over the bridge of the nose from local tissue inflammation. It can be associated with FeLV infection in cats.Cryptococcis is most common in dogs and cats but cattle,sheep,goat,horse,wild animals and birds can also be infected.Soil,fowl manure and pigeon droppings are among the sources of infection. [8][9]

Additional images

References

  1. ^ http://www.umm.edu/ency/article/000642.htm
  2. ^ a b Barron MA and Madinger NE (November 18, 2008). "Opportunistic Fungal Infections, Part 3: Cryptococcosis, Histoplasmosis, Coccidioidomycosis, and Emerging Mould Infections". Infections in Medicine. http://www.consultantlive.com/infection/article/1145625/1404367?pageNumber=1. 
  3. ^ King JW and Dasgupta A (Jun 15, 2007). "Cryptococcosis". EMedicine. http://emedicine.medscape.com/article/215354-overview. 
  4. ^ Makadzange AT, Ndhlovu CE, Takarinda K, Reid M, Kurangwa M, Gona P, Hakim JG (2010). "Early versus delayed initiation of antiretroviral therapy for concurrent HIV infection and cryptococcal meningitis in sub-saharan Africa". Clin Infect Dis 50 (11): 1532–8. doi:10.1086/652652. |pmid= 20415574}
  5. ^ Lane M, McBride J and Archer J "Steroid responsive late deterioration in Cryptococcus neoformans variety gattii meningitis", Neurology 2004;63;713-714
  6. ^ Einsiedel L, Gordon DL, and Dyer JR, "Paradoxical inflammatory reaction during treatment of Cryptococcus neoformans var. gattii meningitis in an HIV-seronegative woman", CID 2004;39:e78–82
  7. ^ Ecevit IZ, Clancy CJ, Schmalfuss IM, and Nguyen MH, "The poor prognosis of central nervous system cryptococcosis among nonimmunosuppressed atients: A call for better disease recognition and evaluation of adjuncts to antifungal therapy", CID 2006;42:1443–7
  8. ^ Deep fungal infections
  9. ^ Malik (2003), "Feline Cryptococcosis"

External links


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Look at other dictionaries:

  • Cryptococcosis — vgl. Kryptokokkose …   Das Wörterbuch medizinischer Fachausdrücke

  • cryptococcosis — /krip toh ko koh sis/, n. Pathol. a disease caused by the fungus Cryptococcus neoformans, chiefly found in soil contaminated by pigeon droppings, and characterized by lesions, esp. of the nervous system and lungs. Also called European… …   Universalium

  • cryptococcosis — An acute, subacute, or chronic infection by Cryptococcus neoformans, causing a pulmonary, disseminated, or meningeal mycosis. The pulmonary form may resolve spontaneously in previously normal persons bu …   Medical dictionary

  • cryptococcosis — noun (plural cryptococcoses) Etymology: New Latin Date: 1938 an infectious disease that is caused by a fungus (Cryptococcus neoformans) and is characterized by the production of lesions in subcutaneous tissues, joints, and especially the lungs,… …   New Collegiate Dictionary

  • cryptococcosis — (krip to kok o sis) An infection caused by the basidiomycete, Cryptococcus neoformans, which may involve the skin, lungs, brain, or meninges …   Dictionary of microbiology

  • cryptococcosis — noun A serious and potentially fatal fungal disease caused by members of the Cryptococcus neoformans species complex, believed to be acquired by inhalation of the infectious propagule from the environment …   Wiktionary

  • cryptococcosis — [ˌkrɪptə(ʊ)kə kəʊsɪs] noun Medicine infestation with a yeast like fungus, resulting in tumours in the lungs. Derivatives cryptococcal adjective Origin 1930s: from mod. L. Cryptococcus (genus name of the fungus) + osis …   English new terms dictionary

  • cryptococcosis — cryp·to·coc·co·sis …   English syllables

  • cryptococcosis — torulosis; n. a disease of worldwide distribution, but recognized mainly in the USA, caused by the fungus Cryptococcus neoformans. The fungus attacks the lung, resulting in a tumour like solid mass (toruloma), but produces few or no symptoms… …   The new mediacal dictionary

  • cryptococcosis — cryp•to•coc•co•sis [[t]ˌkrɪp toʊ kɒˈkoʊ sɪs[/t]] n. pat a disease caused by the fungus Cryptococcus neoformans, characterized by lesions, esp. of the nervous system and lungs • Etymology: 1935–40; < NL; see cryptococcus, osis …   From formal English to slang


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