Emergency: requires immediate attention
Osteomyelitis in Adult
See also in: Cellulitis DDxAlerts and Notices
Synopsis
Osteomyelitis is an inflammatory process of bone secondary to an infection, most commonly bacterial. Osteomyelitis can be caused by contiguous spread of infection from adjacent soft tissues and joints, hematogenous seeding, or direct inoculation of microorganism(s) into the bone as a result of trauma or surgery. Osteomyelitis can complicate ulcers, especially diabetic foot ulcers and decubitus ulcers.Signs and symptoms include fever, malaise, swelling, erythema, tenderness, and decreased range of motion.
Causes / typical injury mechanism: The mechanism by which osteomyelitis occurs varies with nonhematogenous versus hematogenous osteomyelitis.
- Nonhematogenous osteomyelitis occurs as a result of bacteria reaching the bones either via contact with an adjacent soft tissue infection or via direct inoculation (eg, via trauma such as open long bone fractures, surgery, or a bite wound).
- Hematogenous osteomyelitis occurs from inoculation of bone tissue with bacteria from the blood. This typically happens in the setting of bacteremia and/or endocarditis and is much more common in children.
Acute cases of osteomyelitis usually have a gradual onset over the course of several days. The following symptoms are typically present at or within the vicinity of the site of infection:
- Dull pain / tenderness that may or may not be exacerbated by movement
- Warmth
- Swelling
- Erythema
Chronic cases of osteomyelitis may have the same symptoms as acute cases, but pain, erythema, swelling, and other local symptoms might be intermittent in nature. The presence of a sinus tract, a connection between the area of osteomyelitis and the skin, is pathognomonic of chronic osteomyelitis. There may be other surrounding soft tissue insults such as soft tissue / skin ulcerations or diabetic ulcerations. Chronic osteomyelitis can be accompanied by the presence of necrotic bone (sequestrum) that may be surrounded by thickened reactive periosteal bone (involucrum).
Prevalence:
- Age – As an individual ages, the general risk for osteomyelitis increases. Additionally, the locations and pathogenesis of the disease change with age. Generally, pediatric patients will have hematogenous osteomyelitis, although hematogenous osteomyelitis of the vertebral bodies is more common in adults.
- Sex / gender – Men seem to be at higher risk.
Systemic risk factors include:
- Recent surgery
- Recent trauma / bite wounds
- Nicotine use disorder
- Obesity
- Diabetes mellitus
- Preoperative hyperglycemia
- Allergic reaction to hardware used during an orthopedic procedure
- Older age
- Immunocompromised states
- Chronic hypoxia
- Alcohol use disorder
- Malignancies
- Hepatic failure
- Renal failure
- Hypoperfusion
- Peripheral vascular disease
- Peripheral neuropathy
- Systemic infections (eg, endocarditis or bacteremia)
- Intravenous (IV) drug use
- Presence of indwelling intravascular devices
- Hemodialysis
- Sickle cell disease
- Hypoperfusion to the infected region
- Venous stasis
- Presence of surgical components
- Poorly healing soft tissue wounds
The most common causative agent by far of osteomyelitis is Staphylococcus aureus (including methicillin-resistant S aureus [MRSA]). Other common causes include coagulase negative staphylococci (eg, Staphylococcus epidermidis) and aerobic gram-negative bacilli (eg, Pseudomonas aeruginosa). Corynebacteria, fungal species, and mycobacteria are less common causes.
Some species are associated with different underlying conditions:
- Staphylococcus aureus and S epidermidis are associated with IV drug users and patients who have had recent surgery and/or trauma.
- Pseudomonas aeruginosa is associated with diabetic patients.
- Salmonella spp, Streptococcus pneumoniae, and other encapsulated organisms can be associated with sickle cell disease.
- Common organisms responsible for the nosocomial setting include Enterobacteriaceae, P aeruginosa, and Candida spp.
- Fungal infections are especially associated with disseminated disease, which usually affects immunocompromised patients.
- In patients with a history of human or animal bites, consider infection with Pasteurella multocida.
Additional features of pathogenesis include superlative infective processes and accompanying inflammatory features, vascular congestion / small vessel thrombosis, necrotic bone, and formation of new bone. Furthermore, the presence of polymorphonuclear leukocytes and other inflammatory cells plays an important role in the pathogenesis of the disease.
Grade / classification system: Generally, osteomyelitis is classified by the source of the infection (ie, hematogenous or nonhematogenous) or by duration of the condition (ie, acute or chronic).
Of these classifications, osteomyelitis secondary to a contiguous infection (eg, after surgery, insertion of orthopedic hardware, or trauma) is the most common. The next most common cause is vascular insufficiency (eg, diabetic foot infections). Hematogenous origin is the least common cause of osteomyelitis, except in children in whom it is the most common form.
Classification based on the type of bone infected can also be useful, since approaches to treatment are different based on the bone type infected, specifically, long bone versus sternoclavicular versus vertebral versus pelvic versus sacral infection.
Treatment of chronic osteomyelitis includes surgical debridement of any necrotic bone or tissue followed by culture-directed antibiotic therapy. A sequestrum needs to be removed or chronic osteomyelitis may continue or reoccur. Acute osteomyelitis is frequently treatable with antibiotics alone.
Codes
ICD10CM:M86.9 – Osteomyelitis, unspecified
SNOMEDCT:
60168000 – Osteomyelitis
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Diagnostic Pearls
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Differential Diagnosis & Pitfalls
- Soft tissue infection, such as cellulitis, abscess, or necrotizing fasciitis
- Charcot arthropathy
- Osteonecrosis
- Gout
- Fracture
- Bursitis
- Bone tumor
- Sickle cell vaso-occlusive pain crisis
- Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome
- Complex regional pain syndrome (CRPS)
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Therapy
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Drug Reaction Data
Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.Subscription Required
References
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Last Reviewed:07/25/2021
Last Updated:08/04/2021
Last Updated:08/04/2021
Emergency: requires immediate attention
Patient Information for Osteomyelitis in AdultOverview
Osteomyelitis is an infection of the bone that often leads to damage of the skin above the infected bone. It can be caused by many different germs including bacteria, fungi, and viruses. The germs can get into the bone in different ways: through the blood, from an infection in the skin or joints, and directly into the bone by a trauma or surgery. Treating this infection depends on several factors such as what type of germ is causing it, what specific bone is involved, what the blood supply is to the bone, whether there is any loss of sensation, recent injury to the area, and whether there are any other diseases involved.Who’s At Risk
Osteomyelitis can occur at any age and can infect any bone of the body. The people most commonly affected by this bone infection are people with diabetes. It most commonly affects the feet. Other people who are at higher risk for osteomyelitis are people who use intravenous (IV) drugs and people with alcohol use disorder, a poor immune system, or who have rheumatoid arthritis (a disease that affects the joints).Signs & Symptoms
Early symptoms of osteomyelitis include dull pain, swelling, redness, and warmth of the area. Fever and chills may also occur.Late symptoms of osteomyelitis (when it has not been looked at or treated by a doctor) include pus drainage from the infected site and deep wounds of the skin called ulcers that do not heal over time.
Self-Care Guidelines
If you notice redness and swelling in your joints and/or bone and have a hard time moving the area – and these are related to a fever and feeling tired – you should consult your doctor. These symptoms can be highly suggestive of osteomyelitis. This is more likely if you have diabetes, have alcohol use disorder, use IV drugs, or have a weakened immune system.When to Seek Medical Care
As described above, if you notice symptoms in the infected area or symptoms related to an infection (like fever), you should go visit your doctor.When at the doctor's office, he/she may do several tests to determine the diagnosis and the right treatment option.
These tests may include:
- A blood sample
- A culture and/or biopsy of the infected area – to find what germ is present
- Pictures of the bone – X-ray and/or MRI
- A test called arthrocentesis that is done to take a sample of liquid from the joint.
Treatments
Treatment usually begins with surgery to remove dead or damaged skin and bone. Often surgeons will use equipment such as screws and plates to support the damaged bone.People who are treated for osteomyelitis must also be given antibiotics to take for at least 6 weeks. The antibiotics will be given directly into the vein through an "intravenous catheter." In the beginning, the antibiotics are given in the hospital. Then, once the doctors believe a person can be switched to an antibiotic taken by mouth, treatment can be given at home with the help of a nurse or in a rehabilitation facility.