Osteomielytis

Osteomyelitis
Shingo Chihara, MB, and John Segreti, MD
Osteomyelitis is inflammation of the bone that is usually due to infection. The incidence of osteomyelitis is not high because normal bone is highly resistant to infection and tends to occur in patients with risk factors: diabetes, decubitus ulcers, surgery, trauma, and intravenous drug use. Infection occurs when there is a high organisminoculation, trauma leading to bone damage, or foreign bodies. There are several ways to classify osteomyelitis: chronicity (acute vs chronic), Waldvogel classification system based on etiology of the infection (hematogenous spread of an organism, direct inoculation of an organism through trauma, or contiguous spread from a soft tissue infection), and Cierny-Mader classification, which combinesanatomic factors (medullary, superficial, localized, or diffuse) and physiological classes (normal host, systemic and/or local compromise, treatment worse than the disease). The prevalence of osteomyelitis of the extremities has been increasing secondary to the rising prevalence of diabetic foot infections. The pathogen is highly dependent on host factors such as history of trauma, geographic location,immune status, and the age of the patient; and Staphylococcus aureus is the most commonly isolated pathogen in any type of osteomyelitis. Patients with osteomyelitis may present with a variety of symptoms including nonspecific constitutional symptoms, such as chills, fevers, fatigue, irritability, lethargy, or malaise. High clinical suspicion is key to early diagnosis, and identification of thepathogen is crucial for management. Diagnosis is made with a combination of physical examination, imaging studies, and laboratory studies, but the gold standard includes culture and histopathology of the infected bone. Clinicians often send a superficial wound culture from a sinus tract or an ulcer and determine which antibiotics to use for treatment. Unfortunately, the bacteria in the sinus tract oftendo not correlate with the bacteria causing osteomyelitis. Treatment should be guided by cultures obtained from bone and usually requires long-term antibiotics. Surgical intervention should be considered for all cases. Prognosis is dependent on the host factors, the treatment

Dis Mon 2010;56:6-31 0011-5029/2010 $36.00 0 doi:10.1016/j.disamonth.2009.07.001 6 DM, January 2010

modalities, andthe pathogen; and higher recurrence rate occurs in patients with diabetes and peripheral vascular disease. Osteomyelitis is inflammation of the bone that is usually due to infection. It is difficult to treat, often requiring both medical and surgical interventions. The infection may occur due to hematogenous spread of an organism, direct inoculation of an organism through trauma, or contiguous spreadfrom a soft tissue infection. The prevalence of osteomyelitis of the extremities has been increasing secondary to the rising prevalence of diabetic foot infections. Diagnosis is made with a combination of physical examination, imaging studies, and laboratory studies, but the gold standard includes culture and histopathology of the infected bone. Treatment should be guided by cultures obtainedfrom bone and usually requires long-term antibiotics. In this review, we will review extra-axial osteomyelitis and vertebral osteomyelitis in adults.

Terminology
Acute osteomyelitis, which is often used interchangeably with hematogenous osteomyelitis, refers to osteomyelitis before osteonecrosis has occurred.1 By contrast, chronic osteomyelitis is defined as bone infection in the presence ofosteonecrosis, and thus surgical debridement is required for treatment.1

Epidemiology
The incidence of osteomyelitis is not high because normal bone is highly resistant to infection and tends to occur in patients with the following risk factors: diabetes, decubitus ulcers, surgery, trauma, and intravenous drug use. Infection occurs when there is a high organism inoculation, trauma leading to bone...