Secondary Infections in Febrile Neutropenia in Hematological Malignancies: More Than Another Febrile Neutropenic Episode.

Introduction: Febrile neutropenic episodes (FNEs) are among major causes of mortality in patients with hematological malignancies. Secondary infections develop either during the empirical antibiotic therapy or one week after cessation of therapy for a FNE. The aim of the study was to investigate the risk factors associated with secondary infections in febrile neutropenic patients.
Methods: We retrospectively analyzed 750 FNEs in 473 patients between January 2000 and December 2006.
Results: Secondary infections were diagnosed in 152 (20%) of 750 FNEs. The median time to develop secondary infection was 10 days (range 2-34 days). The duration of neutropenia over 10 days significantly increased the risk of secondary infections (p<0.001). The proportion of patients with microbiologically documented infections was found to be higher in primary infections (271/750, 36%) compared to secondary infections (43/152, 28%) (p=0.038). Age, sex, underlying disease, antibacterial, antifungal or antiviral prophylaxis, blood transfusion or bone marrow transplantation, central venous catheter or severity of neutropenia did not differ significantly between primary and secondary infections (p>0.05) While fever of unknown origin (FUO) (p=0.005) and catheter-related bacteremia (p<0.001) were less frequently observed in secondary infections, the frequency of microbiologically (p=0.003) and clinically (p<0.001) documented infections, fungal pneumonias (p<0.001), infections related with gram positive bacteria (p=0.04) and fungi (p<0.001) and 30-day mortality rate (p<0.001) were significantly higher in secondary infections (p<0.001).
Discussion and Conclusion: Secondary infections should be regarded as life-threatening complications of febrile neutropenia. Secondary infections represent a more severe and mortal complication and cannot be regarded just as another febrile neutropenic episode.