Pneumococcal sacroiliitis in a 4-year-old boy.

Pyogenic sacroiliitis is an extremely rare manifestation of invasive pneumococcal disease in childhood as only four cases have been described to date. We report and comment on a case of pneumococcal sacroiliitis in a 4-year-old boy. This patient was diagnosed promptly on account of the symptom triad of fever, buttock pain, and limping gait, along with characteristic findings in magnetic resonance imaging (MRI) and bone scans, and recovered fully after 6 weeks of antimicrobial therapy. Pyogenic sacroiliitis is an uncommon disease in which the diagnosis is often delayed because of nonspecific clinical presentation. The key to successful management is early diagnosis in which MRI and bone scan findings play a crucial role. If the diagnosis is established promptly, most patients can be managed successfully following the therapeutic principles used in other osteoarticular infections.