Osteomyelitis: What You Need To know

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Chapters

0:00 Introduction
0:56 Causes of Osteomyelitis
1:38 Symptoms of Osteomyelitis
2:01 Diagnosis and treatment of Osteomyelitis
3:03 Treatment for Osteomyelitis



Osteomyelitis (OM) is an infection of bone.[1] Symptoms may include pain in a specific bone with overlying redness, fever, and weakness.[1] The long bones of the arms and legs are most commonly involved in children e.g. the femur and humerus,[7] while the feet, spine, and hips are most commonly involved in adults.[2]

The cause is usually a bacterial infection, but rarely can be a fungal infection.[8] It may occur by spread from the blood or from surrounding tissue.[4] Risks for developing osteomyelitis include diabetes, intravenous drug use, prior removal of the spleen, and trauma to the area.[1] Diagnosis is typically suspected based on symptoms and basic laboratory tests as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR).This is because plain radiographs are unremarkable in the first few days following acute infection.[7][2] Diagnosis is further confirmed by blood tests, medical imaging, or bone biopsy.[2]

Treatment of bacterial osteomyelitis often involves both antimicrobials and surgery.[7][4] In people with poor blood flow, amputation may be required.[2] Treatment of the relatively rare fungal osteomyelitis as mycetoma infections entails the use of antifungal medications.[9] In contrast to bacterial osteomyelitis, amputation or large bony resections is more common in neglected fungal osteomyelitis, namely mycetoma, where infections of the foot account for the majority of cases.[8][9] Treatment outcomes of bacterial osteomyelitis are generally good when the condition has only been present a short time.[7][2] About 2.4 per 100,000 people are affected each year.[6] The young and old are more commonly affected.[7][1] Males are more commonly affected than females.[3] The condition was described at least as early as the 300s BC by Hippocrates.[4] Prior to the availability of antibiotics, the risk of death was significant.[10] Symptoms may include pain in a specific bone with overlying redness, fever, and weakness and inability to walk especially in children with acute bacterial osteomyelitis.[7][1] Onset may be sudden or gradual.[1] Enlarged lymph nodes may be present.[11] In fungal osteomyelitis, there is usually a history of walking bare-footed, especially in rural and farming areas. Contrary to the mode of infection in bacterial osteomyelitis, which is primarily blood-borne, fungal osteomyelitis starts as a skin infection, then invades deeper tissues until it reaches bone.[8]In children, the metaphyses, the ends of long bones, are usually affected. In adults, the vertebrae and the pelvis are most commonly affected.[7]

Acute osteomyelitis almost invariably occurs in children who are otherwise healthy, because of rich blood supply to the growing bones. When adults are affected, it may be because of compromised host resistance due to debilitation, intravenous drug abuse, infectious root-canaled teeth, or other disease or drugs (e.g., immunosuppressive therapy).[7]

Osteomyelitis is a secondary complication in 1–3% of patients with pulmonary tuberculosis.[13] In this case, the bacteria, in general, spread to the bone through the circulatory system, first infecting the synovium (due to its higher oxygen concentration) before spreading to the adjacent bone.[13] In tubercular osteomyelitis, the long bones and vertebrae are the ones that tend to be affected.[13]

Bloodstream-sourced osteomyelitis is seen most frequently in children, and nearly 90% of cases are caused by Staphylococcus aureus. In infants, S. aureus, Group B streptococci (most common[14]) and Escherichia coli are commonly isolated; in children from one to 16 years of age, S. aureus, Streptococcus pyogenes, and Haemophilus influenzae are common. In some subpopulations, including intravenous drug users and splenectomized patients, Gram-negative bacteria, including enteric bacteria, are significant pathogens.[15]

The most common form of the disease in adults is caused by injury exposing the bone to local infection. Staphylococcus aureus is the most common organism seen in osteomyelitis, seeded from areas of contiguous infection. But anaerobes and Gram-negative organisms, including Pseudomonas aeruginosa, E. coli, and Serratia marcescens, are also common.

Systemic mycotic infections may also cause osteomyelitis. The two most common are Blastomyces dermatitidis and Coccidioides immitis.[citation needed]

In osteomyelitis involving the vertebral bodies, about half the cases are due to S. aureus, and the other half are due to tuberculosis (spread hematogenously from the lungs). Tubercular osteomyelitis of the spine was so common before the initiation of effective antitubercular therapy, it acquired a special name, Pott's disease.[citation needed]

The Burkholderia cepacia complex has been implicated in vertebral osteomyelitis in intravenous drug users.[16]