Community respiratory viruses as a cause of lower respiratory tract infections following suppressive chemotherapy in cancer patients.

BACKGROUND AND PURPOSE Community respiratory viruses are an important cause of respiratory disease in the immunocompromised patients with cancer. To evaluate the occurrence and clinical significance of respiratory virus infections in hospitalized cancer patients at National Cancer Institute, Cairo University, during anticancer treatment, we studied cases that developed episodes of lower respiratory tract infections (LRTI). PATIENTS AND METHODS Thirty patients with LRTI were studied clinically, radiologically, and microbiologically. Sputum cultures were done and an immunofluorescence search for IgM antibodies of influenza A and B, parainfluenza serotypes 1, 2 and 3, adenovirus, respiratory syncytial virus, Legionella pneumophila, Coxiella burnettii, Chlamydia pneumoniae, and Mycoplasma pneumoniae were performed on serum samples of patients. RESULTS The main presenting symptom was cough and expectoration. Hematologic malignancy was the underlying disease in 86.6% of cases. Blood cultures were positive in 11 patients (36.6%) only. Sputum cultures revealed a bacterial pathogen in 13 cases and fungi in 3; whereas viral and atypical bacterial IgM antibodies were detected in 13 and 4 patients; respectively. Influenza virus was the commonest virus detected, being of type B in 4 cases, type A in one case and mixed A and B in another 5 cases; followed by RSV in 5 patients. Taken together, bacteria were identified as a single cause of LRTI in 10 cases, viruses in 6, fungi in 3 and mixed causes in 7. Still, there were 4 undiagnosed cases. CONCLUSIONS This study showed that respiratory viruses are common in LRTI, either as a single cause or mixed with bacterial pathogens, in hospitalized cancer patients receiving chemotherapy. Diagnostic tests for respiratory viruses should be incorporated in the routine diagnostic study of patients with hematologic malignancies. Also, it must be emphasized that early CT chest is crucial as a base-line prior to initiation of anti-fungal or anti-viral therapy. In cancer patients with a febrile episode and LRTI, tailored therapy is recommended according to the clinical findings of the patient.