Review Question - QID 191

The child's clinical presentation is consistent with an acute infection. However, results from the aspiration are not consistent with septic arthritis of the knee. The child most likely has acute osteomyelitis. Therefore, MRI will confirm diagnosis and assist in planning a bone biopsy and culture to guide antibiotic management.

McCarthy et al. reviewed the current evaluation, diagnosis, and management of pediatric osteomyelitis. They emphasized prompt and accurate diagnosis, timely medical and/or surgical intervention, and long-term follow-up as paramount to achieving clinical success.

Peltola & Pääkkönen reviewed the diagnosis and management of acute osteomyelitis in children and note that there is a predilection for osteomyelitis in the long bones (i.e., femur). They present an algorithm for the diagnosis and management of osteomyelitis (Illustration A).

Figure A and B are unremarkable AP and lateral radiographs of the knee. Radiographs in patients with osteomyelitis may show deep soft tissue swelling, but are unlikely to show osseous changes during an acute episode. Illustration A depicts the recommendations from Peltola & Pääkkönen regarding the diagnosis and management of osteomyelitis.

Incorrect Answers:
Answer 2: Observation with repeat ESR and CRP would be appropriate if suspicion for infection was low and ESR and CRP were not already elevated.
Answer 3: Oral cephalosporins for 10 days would not be indicated at this time. First a diagnosis of osteomyelitis is required and if confirmed intravenous, not oral, antibiotic therapy should be initiated.
Answer 4: Surgical arthrotomy, debridement and irrigation would be more appropriate if the results from the aspiration confirmed a septic arthritis.
Answer 5: Chest, abdomen and pelvis CT would be more appropriate if there was a clinical suspicion for malignancy.