Classification of Chemotherapy-Induced Febrile Neutropenic Episodes Into One of the Three Febrile Neutropenic Syndromes

Introduction Febrile neutropenia is a commonly encountered medical emergency in patients undergoing cancer treatment and can delay and modify the course of treatment and even lead to dire outcomes, including death. The cause of fever in a post-chemotherapy-induced neutropenic patient can be confusing to treating physicians. A review of the literature demonstrated that blood culture results could determine the cause of febrile neutropenia in only approximately 10% to 25% of patients. The objective of our study was to measure the incidence of positive blood cultures, urine cultures, and other body fluid cultures resulting in chemotherapy-induced neutropenia and further classify fever episodes into three neutropenic fever syndromes, such as microbiologically documented, clinically suspected, or unknown causes of fever, respectively. Methods We conducted a prospective observational study on 399 chemotherapy-induced neutropenic fever episodes with the aim of classifying them into one of the three neutropenic syndromes. We tried to document the cause of the fever in these patients. We also noted the type of cancer treatment regimen they were on and correlated their clinical profile with their body fluid cultures, including blood cultures, urine cultures, and other body fluid cultures. We then categorized each fever episode into one of three neutropenic syndromes. Results We studied 399 febrile neutropenic episodes. We were able to microbiologically document the cause of fever in 39% of the cases, and we obtained growth in 51 out of 399 blood cultures (13%), which was comparable to the available literature, and urine culture showed growth in 62 out of 399 cultures (16%), while other body cultures such as pus culture, bile culture, and bronchioalveolar lavage cultures collectively showed growth in 42 out of 399 episodes (10%). The most common bacteria isolated in both blood and urine cultures were Escherichia coli. Cumulatively, including blood, urine, and body fluid cultures, we were able to classify 39% (155 out of 399 cases) of febrile neutropenic episodes as microbiologically documented. The cause of fever was clinically suspected by means of careful history taking and an extensive physical examination in 31% (125 out of 399) without growth evidence in blood cultures, urine cultures, or any other body fluid culture. The cause of fever remained unknown in 119 cases (30%) of patients and was classified under the unknown cause of fever. Conclusions We conclude by stating that the study of fever in a neutropenic patient should include a thorough history and clinical evaluation of blood, urine, and other body fluid cultures instead of solely relying on blood culture results. We recommend further classifying patients into one of the three neutropenic fever syndromes, such as those that are microbiologically documented, clinically suspected, or unknown. Our blood cultures were able to give us a 13% positivity rate, whereas microbiologically, we were able to isolate an organism likely causing fever in 39% of patients. The cause of fever was suspected clinically in 31% of patients, but we were unsuccessful in microbiologically documenting any culture growth in blood, urine, or any other body fluid culture. The cause of fever remained a mystery and unknown to us without any microbiological or clinical cues in 119 cases (30%) of febrile neutropenic episodes.