Diagnosis and antimicrobial therapy of lung infiltrates in febrile neutropenic cancer patients.

Pulmonary infiltrates develop in up to 25% of febrile neutropenic patients and are frequently refractory to broad-spectrum antibacterial therapy. Etiologically, Aspergillus spp., Pneumocystis jiroveci, multi-resistant Gram-negative rods as well as mycobacteria and respiratory viruses may be involved. Taking into account the predominant role of fungal pathogens, typically without microbiological proof, prompt addition of mold-active systemic antifungal therapy improves clinical outcome, while other microorganisms should typically be targeted based upon microbiological test results only. Microbial isolates from blood cultures, bronchoalveolar lavage or respiratory secretions must be critically interpreted with respect to their etiological relevance for pulmonary infiltrates. Non-culture based diagnostic procedures to detect circulating antigens such as galactomannan or 1,3-beta-D-glucan, or PCR techniques to amplify DNA from blood, bronchoalveolar lavage or tissue specimens, may facilitate the diagnosis. For pre-emptive antifungal treatment, voriconazole or liposomal amphotericin B are preferred. Antifungal treatment should be continued for at least 14 days before non-response and treatment modification are considered. Primary choice for treatment of Pneumocystis pneumonia remains high-dose trimethoprim-sulfamethoxazole, while cytomegalovirus pneumonia is treated with ganciclovir in the majority of patients affected.