Acute Hematogenous Osteomyelitis of the Foot and Ankle in Children

Abstract

Acute hematogenous osteomyelitis may develop when a blood-born bacteria enters the nutrient artery of a bone and lodges in the metaphysis. The site of the infection may be made vulnerable by concurrent nonpenetrating trauma. This is called the bone bruise theory. Bacterial proliferation in the metaphysis initiates a series of inflammatory events leading to bone destruction and periosteal new bone formation. Symptoms are pain with palpation over the bone, erythema, and swelling. Systemic signs of infection such as fever, malaise, and anorexia accompany the focal signs. Laboratory studies of inflammation such as sedimentation rate, white blood count and differential, and c-reactive protein may help confirm or refute clinical impressions. Cultures of blood and aspirates or debrided bone tissue are the most important investigations. Staphyloccus aureus is the most common infecting organism. Others include Staphylococcus epidermidis, Streptococcus pyogenes and a variety of gram negative bacteria such as Kingella kingiae and Pseudomonas aeruginosa. The calcaneus is the most commonly infected foot bone. All others especially the talus and metatarsals are vulnerable. Optimal treatment entails judicious needle aspiration or open biopsy with debridement of the lesion. Specimens are sent for culture and susceptibility testing. Ten to fourteen days of intravenous antibiotics followed by another 2 weeks of oral antibiotic therapy will provide for optimal outcome.