1. Anjali Jain, MD* 2. Tamar Ben-Ami, MD* 3. Robert S. Daum, MD* 1. 2. *From the Departments of Pediatrics and Radiology, Section of Infectious Diseases, The University of Chicago, Chicago, IL. After completing this article, readers should be able to: 1. Plan the strategy for investigation of a child who has putative osteomyelitis. 2. Describe the circumstances in which the finding of coagulase-negative staphylococcal bacteriuria may be of clinical importance. 3. Describe the clinical features that should prompt consideration of staphylococcal pneumonia in a child who has respiratory distress. 4. Plan the management of a child who has hematogenous osteomyelitis or osteochondritis of the foot due to a puncture wound. Staphylococcus aureus is the major cause of hematogenous osteomyelitis and accounts for about 90% of cases. It also is an important cause of osteomyelitis secondary to an adjacent focus, where organisms are either inoculated directly into bone (eg, by trauma) or gain access into bone through an adjacent infective focus. ### HEMATOGENOUS OSTEOMYELITIS #### Clinical Presentation In hematogenous osteomyelitis, the metaphyses of long, tubular bones are affected most frequently, although infection may occur in any bone. A child may be predisposed to infection by a previous minor trauma; the mechanism is probably the result of a subclinical minor vascular injury, with a small area of bony necrosis acting as a nidus for seeding during what otherwise would have been a subsequent asymptomatic bacteremia. The classic clinical picture includes fever, pain in the area where the bone is infected, decreased range of motion of the relevant bones, and local signs of inflammation. Because these symptoms and signs may be absent, diagnosis requires a high degree of suspicion. Prior to coming to medical attention, the duration of symptoms usually is 1 week or less, but occasionally it may be several months. #### Diagnosis Laboratory and radiologic investigations may help support the diagnosis of osteomyelitis, and a blood culture may reveal the causative organism. Bacteremia is detected in about 50% of patients. At the time of clinical presentation, the erythrocyte sedimentation rate (ESR) and C-reactive protein …