The spectrum of pulmonary infections in cancer patients

The lung is a common site of infection in patients with cancer. The spectru m of pulmonary infection depends on the underlying immunologic deficit or d eficits. In neutropenic patients, gram-negative bacterial infections predom inate early, whereas fungal infections (Aspergillus, Zygomycetes, Fusarium species) are common if neutropenia persists. In patients with impaired cell ular immunity, viral infections (cytomegalovirus, other herpes viruses) pre dominate and may coexist with bacterial (Legionella, Nocardia), mycobacteri al, and fungal (Aspergillus, Histoplasma, etc.) infections. Pneumocystis ca rinii pneumonia is also common in this setting. Infections caused by Strept ococcus pneumoniae and Haemophilus influenzae are the primary bacterial inf ections encountered in patients with impaired humoral immunity. In patients with primary or metastatic pulmonary neoplasms, postobstructive pneumoniti s, lung abscess, and occasionally empyema of mixed bacterial etiology (Stap hylococcus species, gram-negative bacilli, anaerobes) are frequent. Patient s with brain tumors and head and neck cancer develop aspiration pneumonitis , which is usually caused by organisms living in the oropharynx and upper a irways. Several immunologic deficits might be present in the same patient, making such a patient susceptible to a wide variety of opportunistic pathog ens.(C) 2001 Lippincott Williams & Wilkins, Inc.