In a more recent study, Agrawal et al [35] demonstrated a similar distribution of positive findings among body regions but found that only 2 of the initial positive CT scans led to a change in management (6.5% of positive scans, 0.8% of all initial scans). They therefore recommend limiting initial empiric CT imaging to the chest only in patients without localizing signs or symptoms. Regarding the use of FDG-PET/CT, Blokhuis et al [39] found a 78% sensitivity and 67% specificity in 12 of such children. Variant 6: Infant or child more than 1 month of age with fever of unknown origin (FUO). Occult infection is the usual cause of FUO in children and is less commonly due to rheumatologic, autoimmune, neoplastic, or other inflammatory conditions [9,20,24,27,66,67]. Some children never have a specific diagnosis reached [9,24]. Evaluation of FUO in children is mainly based on thorough physical examination, history, and laboratory studies such as a complete blood cell count and peripheral smear, erythrocyte sedimentation rate, C- reactive protein, aerobic blood cultures, urinalysis, urine culture, tuberculin skin test, electrolytes, blood urea nitrogen, creatinine, hepatic enzymes, and human immunodeficiency virus serology [9,20,24,27,68,69]. Chest radiographs are usually obtained to evaluate for occult pneumonia and lymphadenopathy. Although many studies describe the clinical course of such patients, few of them examine the utility of diagnostic imaging modalities in these difficult patients. In general, if a detailed review of the history, physical examination, and screening evaluation fail to suggest a diagnosis, more extensive imaging can be considered. This includes abdominal ultrasound (US) and CT studies of the chest, abdomen, and paranasal sinus [4]. Steele et al [70] evaluated 109 children with FUO with conventional radionuclide techniques. These studies were often positive but rarely led to an unsuspected diagnosis.
Fever Without Source or Unknown Origin Child. In a more recent study, Agrawal et al [35] demonstrated a similar distribution of positive findings among body regions but found that only 2 of the initial positive CT scans led to a change in management (6.5% of positive scans, 0.8% of all initial scans). They therefore recommend limiting initial empiric CT imaging to the chest only in patients without localizing signs or symptoms. Regarding the use of FDG-PET/CT, Blokhuis et al [39] found a 78% sensitivity and 67% specificity in 12 of such children. Variant 6: Infant or child more than 1 month of age with fever of unknown origin (FUO). Occult infection is the usual cause of FUO in children and is less commonly due to rheumatologic, autoimmune, neoplastic, or other inflammatory conditions [9,20,24,27,66,67]. Some children never have a specific diagnosis reached [9,24]. Evaluation of FUO in children is mainly based on thorough physical examination, history, and laboratory studies such as a complete blood cell count and peripheral smear, erythrocyte sedimentation rate, C- reactive protein, aerobic blood cultures, urinalysis, urine culture, tuberculin skin test, electrolytes, blood urea nitrogen, creatinine, hepatic enzymes, and human immunodeficiency virus serology [9,20,24,27,68,69]. Chest radiographs are usually obtained to evaluate for occult pneumonia and lymphadenopathy. Although many studies describe the clinical course of such patients, few of them examine the utility of diagnostic imaging modalities in these difficult patients. In general, if a detailed review of the history, physical examination, and screening evaluation fail to suggest a diagnosis, more extensive imaging can be considered. This includes abdominal ultrasound (US) and CT studies of the chest, abdomen, and paranasal sinus [4]. Steele et al [70] evaluated 109 children with FUO with conventional radionuclide techniques. These studies were often positive but rarely led to an unsuspected diagnosis.