| Abstract: | Pneumocystis jirovecii is an atypical fungus that causes Pneumocystis pneumonia in immunocompromised patients. Underlying diseases associated with Pneumocystis pneumonia mainly consist of hematologic malignancies, solid tumors, organ transplant recipients and inflammatory disorders. Currently, inflammatory disorders represent 20% of underlying diseases. Corticosteroids are considered as a major risk factor. Recently introduced immunosuppressive drugs, such as antitumor necrosis factor monoclonal antibodies, could enhance the risk of Pneumocystis pneumonia. In patients with inflammatory disorders, lymphopenia is probably a determining factor but CD4+ T-cell count associated with the risk of Pneumocystis pneumonia remains unassessed. The diagnosis is based upon clinical, radiologic and biologic data. The identification of P. jirovecii usually requires a lower respiratory tract specimen, even if oral washes samples seem to be promising. According to recent data, immunofluorescent stains should be considered as the new gold standard, and specialized techniques such as PCR should be applied for sputum samples or oral washes. Recommendations on prophylaxis remains controversial except in patients with Wegener's granulomatosis and systemic lupus erythematosus. Cotrimoxazole is the preferred agent for prophylaxis as well as for treatment. An adjunctive corticosteroid therapy is usually prescribed despite the lack of evidence for utility in patients with inflammatory disorders. As person-to-person transmission is the most likely mode of acquiring P. jirovecii, isolation precautions should be advised. |
