Abstract
Pneumocystis jirovecii (previously known as Pneumocystis carinii), a yeast-like, atypical fungus, is an important human pathogen especially in the
immunocompromised hosts. It primarily causes pneumonia (P. jirovecii pneumonia or PJP), but rarely can infect other extrapulmonary sites, such as lymph
nodes, spleen, liver, and bone marrow. Though an early age of colonization/infection
has been documented even in healthy children, children with human immunodeficiency
virus (HIV) infection, those with immunosuppression secondary to malignancies, cancer
chemotherapy, and other immunosuppressive agents, and primary immunodeficiency are
the ones primarily affected with the disease. The mode of presentation is variable
depending on the underlying disease, immune status, and age of the patient, but clinical
features of PJP are largely nonspecific. Though diffuse, perihilar predominant, bilaterally
symmetrical interstitial infiltrates with apical sparing is characteristically seen
in pulmonary imaging, it is very difficult to differentiate between PJP and other
causes of pneumonia in immunocompromised hosts. The growth of the organism being extremely
difficult in the laboratory, direct demonstration of the organism or its DNA in pulmonary
secretions (induced sputum, bronchoalveolar lavage [BAL], etc.) by either direct stains
or polymerase chain reaction (PCR) is the predominant mode of diagnosis. Chemoprophylaxis
is indicated for HIV-infected infants and other children with profound immunosuppression.
Co-trimoxazole is the drug of choice for both prophylaxis and therapy in children
with PJP; pentamidine, atovaquone, dapsone, and clindamycin/primaquine are other alternatives.
Following the advent of highly active antiretroviral therapy (HAART) for the treatment
of HIV disease and co-trimoxazole prophylaxis, both the incidence of PJP and associated
mortality have decreased dramatically in the developing regions. Developing countries
still have very high morbidity and mortality with PJP, especially in HIV-infected
children.
Keywords
immunosuppression - HIV/AIDS - Co-trimoxazole
