The early diagnosis of sacroiliac joint infections in children.

UNLABELLED: We retrospectively reviewed the medical records and imaging studies of 15 children with infections of the sacroiliac joint to determine the usefulness of specific examinations and studies to aid in the early diagnosis of this condition. The clinical presentation, physical examination findings, pertinent laboratory data, and imaging studies were reviewed. Thirteen patients (87%) were febrile at the time of presentation. One patient presented in septic shock requiring intubation and critical care management. Tenderness to palpation over the sacroiliac joint was present in all 9 patients who had this examination performed, and the flexion abduction external rotation test was positive in 10 of 12 patients (83%) who had this test done. Laboratory indicators of infection were elevated in most patients, and 6 patients (46%) had positive blood cultures, most commonly growing Staphylococcus aureus. Initial conventional radiographs were negative in all but 1 patient. Radionuclide 99-m-technetium bone scans were positive in 7 of 10 patients (70%), and magnetic resonance imaging studies were ultimately positive in 13 of 14 patients (93%). However, within the first 6 days after the onset of symptoms, only 5 of 8 bone scans (63%) and 5 of 9 magnetic resonance imaging studies (57%) were consistent with infection. We conclude that while diagnostic imaging studies are ultimately helpful in confirming the diagnosis of sacroiliac joint infections in children, studies made within 6 days of the onset of symptoms may not always confirm the diagnosis. The early diagnosis of this condition is best made on the basis of clinical and laboratory findings. LEVEL OF EVIDENCE: Therapeutic Study, level IV (Case series [no, or historical control group]).