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Extrapulmonary pneumocystosis
V L Ng1, D M Yajko, W K Hadley
1Department of Laboratory Medicine, University of California San Francisco, USA. ng@pangloss.ucsf.edu
Abstract:
Extrapulmonary pneumocystosis is an exceedingly rare complication of Pneumocystis carinii pneumonia (PCP). Prior to the advent of the human immunodeficiency virus type 1 (HIV-1) epidemic, only 16 cases of extrapulmonary pneumocystosis in individuals who were immunocompromised by a variety of underlying diseases had been reported. Since the beginning of the HIV-1 and related PCP epidemic, at least 90 cases of extrapulmonary pneumocystosis have been reported. This review briefly presents a history of the discovery of P. carinii and its recognition as a human pathogen, the controversy regarding its taxonomy, and the epidemiology of this organism. A more detailed analysis of the incidence of extrapulmonary pneumocystosis in HIV-1-infected individuals and its occurrence despite widespread prophylaxis for PCP with either aerosolized pentamidine or systemic dapsone-trimethoprim is presented. The clinical features of published cases of extrapulmonary pneumocystosis in non-HIV-1-infected individuals are summarized and contrasted with those in HIV-1 infected individuals. The diagnosis of extrapulmonary pneumocystosis is discussed, and because clinical microbiologists and pathologists are the key individuals in establishing the diagnosis, the characteristic microscopic morphology of P. carinii as its appears when stained with a variety of stains is presented and reviewed. The review concludes with a brief discussion of treatments for extrapulmonary pneumocystosis.
Insights
Extrapulmonary pneumocystosis, a rare complication of Pneumocystis pneumonia (PCP), has increased significantly with the HIV epidemic. This review details its occurrence, diagnosis, and treatment in both HIV-infected and non-HIV individuals.
Area of Science:
- Infectious Diseases
- Microbiology
- Immunology
Background:
- Extrapulmonary pneumocystosis is a rare complication of Pneumocystis pneumonia (PCP).
- Prior to the HIV epidemic, only 16 cases were reported; since the epidemic, over 90 cases have been documented.
- The review covers the history, taxonomy, and epidemiology of Pneumocystis carinii.
Purpose of the Study:
- To analyze the incidence of extrapulmonary pneumocystosis in HIV-infected individuals.
- To contrast clinical features in HIV-infected versus non-HIV-infected individuals.
- To discuss diagnostic methods, including microscopic morphology, and treatment options.
Main Methods:
- Literature review of published cases of extrapulmonary pneumocystosis.
- Analysis of incidence data in HIV-infected populations.
- Summary and comparison of clinical features and diagnostic findings.
Main Results:
- A significant increase in extrapulmonary pneumocystosis cases since the HIV-1 epidemic.
- Occurrence of extrapulmonary pneumocystosis despite prophylaxis in HIV-infected individuals.
- Distinct clinical presentations in HIV-infected versus non-HIV-infected patients.
Conclusions:
- Extrapulmonary pneumocystosis is more common in HIV-infected individuals, even with prophylaxis.
- Accurate diagnosis relies on recognizing characteristic microscopic morphology.
- Understanding clinical features and diagnostic methods is crucial for patient management.