Immunoscintigraphy (BW 250/183) in neonates and infants with fever of unknown origin

Fever of unknown origin is defined as a temperature above 39.0 degrees C together with a white blood cell count > or = 15,000 mm-3, the duration of fever exceeding 2 weeks and a correct diagnosis not being obtained in the first week of hospitalization. In neonates and infants with fever of unknown origin, the localization of the infectious focus is often difficult and unsatisfactory. In this retrospective study, the clinical value of 99Tcm-labelled antigranulocyte antibodies for this group of patients was investigated. Thirty-two immunoscintigrams were performed using 185-259 MBq 99Tcm-labelled antigranulocyte antibodies (BW 250/183) in 30 neonates and infants (21 boys, 9 girls, mean age 29.4 +/- 2 months), who had fever of unknown origin. Immunoscintigraphy was carried out as whole-body images (n = 7) or single planar images (n = 25) 4 h and 24 h post-injection. In children with known cardiac failure, single photon emission tomography of the thorax was performed to diagnose endocarditis (n = 2). For verification, the results of the immunoscintigrams were compared with radiology (conventional radiography = 14, MRI = 5, CT = 3), biopsy (n = 2), blood culture (n = 10) and clinical follow-up after specific therapy. In 11 of 30 children (36%), the diagnosis of an infective focus was possible with immunoscintigraphy. The sensitivity and specificity of diagnosing infective foci was 72% and 95% respectively (n = 11; colitis = 2, infection of the central permanent catheter tip = 2, middle ear infection = 1, spondylitis/discitis = 3, osteomyelitis = 2, umbilical infection = 1). In vertebral body infections, all lesions were photopenic. In 18 children (60%), no infective focus was found on immunoscintigraphy. In this group of children, the main reason (n = 5) for fever of unknown origin was chronic juvenile rheumatoid arthritis. No uptake was seen in two infants with cardiac failure and suspected endocarditis on SPET. In 3 of the 18 patients (17%), localization of an infective focus was not possible with immunoscintigraphy or on other examinations. In these patients, the fever disappeared spontaneously after a few days of antibiotic therapy. In conclusion, we have shown that 99Tcm-anti-NCA-95 scanning is a safe method with a high sensitivity and specificity for detecting infectious foci in neonates and infants with fever of unknown origin. Furthermore, this method is easy to perform, since no withdrawal of blood is necessary.