Fever of unknown origin: Treatment according to risk assessment

Abstract

Although the risk of developing fever and infection is already increased when a patient’s neutrophil granulocyte counts fall below 1,000 per mm3, counts of less than 500 per mm3have been demonstrated to be the most critical risk factor for the development of serious infectious complications. Expert groups of the Infectious Diseases Society of America (IDSA), the European Conference on Infections in Leukaemia (ECIL), the Multinational Association for Supportive Care in Cancer, the American Society of Clinical Oncology, and the German Society of Hematology and Oncology have categorized neutropenic patients into distinct subgroups with different risk profiles depending upon their duration of neutropenia (see also the chapter by Paesmans). While a strict prospective allocation of all patients to distinct risk groups is not possible in clinical practice, patients with neutropenia lasting for up to 7 days, who have no additional risk factors such as open wounds and tumor-associated obstruction of airways or bile ducts, e.g., patients with malignant lymphoma on standard chemotherapy, are regarded as low-risk patients. In contrast, patients with aggressive hematologic malignancies such as acute leukemias undergoing intensive chemotherapy, who have an expected duration of profound neutropenia of more than 7 days, represent a high-risk group. Sometimes, patients with an expected neutropenia of 7–10 days, e.g., those with lymphomas receiving dose-intensified treatment regimens, are regarded as a separate, so-called intermediate or standard risk group.