Key Points
ÎFever during chemotherapy-induced neutropenia may be the only indication of a severe underlying infection since signs and symptoms of inflammation typically are attenuated.
Î10% to 50% of patients with solid tumors and > 80% in those with hematologic malignancies will develop fever during one or more chemotherapy cycles associated with neutropenia.
ÎAll patients who present with fever and neutropenia should be treated empirically, swiftly and broadly, with antibiotics primarily directed against serious Gram-negative pathogens that may cause life- threatening sepsis.
ÎClinically documented infections occur in 20-30% of febrile episodes.
> Common sites of tissue-based infection include the intestinal tract, lung, and skin. > Bacteremia occurs in 10-25% of all patients, with most episodes occurring in the setting of prolonged or profound neutropenia (absolute neutrophil count less than 100 neutrophils/mm3
).
ÎResistant Gram-positive pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococcus (VRE), have become more common and are the most prevalent resistant isolates in some centers, accounting for 20% to over 50% of episodes, respectively.
> Penicillin-resistant strains of S. pneumoniae and of viridans group streptococci are less common but may cause severe infections.
ÎFungi are rarely identified as the cause of first fever early in the course of neutropenia. Rather, they are encountered after the first week of prolonged neutropenia and empirical antibiotic therapy.
Definitions
ÎFever is defined as a single oral temperature measurement of ≥ 38.3°C (101°F) or a temperature ≥ 38.0°C (100.4°F) sustained over 1 hour.
ÎNeutropenia is defined as an absolute neutrophil count (ANC) of less than 500 cells/mm3 over the next 48 hours.
or one that is expected to fall below 500/mm3
ÎThe term "profound" is sometimes used to describe neutropenia where the ANC is below 100 cells/mm3
.
ÎThe term "functional neutropenia" refers to patients whose hematologic malignancy results in qualitative defects (impaired phagocytosis and killing of pathogens) of circulating neutrophils. These patients should be considered at increased risk for infection despite a "normal" neutrophil count.
