Fever of unknown origin in pediatrics: role of nuclear medicine.

Fever of unknown origin (FUO) is a debated issue in numerous scientific studies in adult patients with a not jet-defined workflow in a clinical and diagnostic setting. Few works are published about pediatric patients even if FUO represents a challenging, not infrequent scenario in hospital and outpatient recovery. The fever might be the onset symptom of a transient mild infection or the beginning of a more difficult-to-diagnose and serious pathological condition. In the adult workflow ¹⁸FDG PET-CT is nowadays playing a relevant role, considering the limited spread of conventional ^99mTc-HMPAO-White Blood Cells scintigraphy. It represents a robust tool for diagnosing the eventual site of infection, but it is limited by procedural complexity and long duration, up to 24 hours. The WBC-scintigraphy is also not suitable for children, only for young adults or adolescents, considering the relevant blood sample entity and the procedural risk for sensitive subjects. The most assessed clinical and diagnostic know-how on Pediatric FUO are summarized and a synthetic flow-chard is presented to support the clinical management and to choose the best diagnostic pathway.