Bone Infections - Osteomyelitis

Overview, Causes, & Risk Factors

Osteomyelitis describes serious bone infections that go deep into the affected bones.

What is going on in the body?

In almost all cases, this condition is caused by a bacterial infection. These infections usually occur in one of two ways:

An infection may occur in another part of the body and spread though the blood and into a bone.

A breakdown in the skin allows bacteria to go directly into the underlying bone. People with this type of infection often need long-term treatment with antibiotics and, sometimes, surgery.

What are the causes and risks of the infection?

A bacteria called Staphylococcus aureus causes most cases. However, other bacteria are also possible culprits. The bacteria may enter the bone through the bloodstream or through the skin.

The following conditions increase a person's risk for developing osteomyelitis:

trauma to the skin or bones, such as surgery, deep skin cuts, and bone fractures or breaks

chronic skin infections

diabetes, a condition that causes high blood sugar levels

poor circulation, which can be caused by diabetes, smoking, and high blood pressure

intravenous drug use, common among heroin users

artificial joints, such as a knee joint replacement or hip joint replacement

sickle cell anemia, an inherited condition that causes abnormal red blood cells

Symptoms & Signs

What are the signs and symptoms of the infection?

Common symptoms include:

constant bone pain, usually in a specific area

fever

skin inflammation with redness, heat, drainage of pus, or swelling

The affected skin lies directly over the affected bone. Skin changes only occur in certain cases.

Diagnosis & Tests

How is the infection diagnosed?

Diagnosis starts with the history and physical exam. This may be all that is needed to make the diagnosis. In some cases, further tests are needed. These may include blood tests and x-rays. Many different types of x-rays may be done, including standard x-rays, an imaging test called an MRI, or other special scans. In some cases, a sample of bone or pus from deep inside a skin wound is examined. Surgery or insertion of a needle through the skin may be needed to obtain these samples.

Prevention & Expectations

What can be done to prevent the infection?

Most cases cannot be prevented. Avoidance of intravenous drug use can prevent cases from this cause. Proper treatment of diabetes and high blood pressure and avoidance of smoking may prevent cases due to poor circulation.

What are the long-term effects of the infection?

Many cases are difficult to treat. Severe cases may result in death or loss of a limb. Chronic or repeated infections may occur. These may require multiple surgeries.

What are the risks to others?

This condition is not contagious and generally poses no risk to others.

Treatment & Monitoring

What are the treatments for the infection?

Antibiotics are usually given for 4 or more weeks. If the infection goes away, no further treatment is needed. This most commonly occurs in children with a first-time infection. Pain medication can be given if needed.

Surgery is often needed, especially in those with diabetes, poor circulation, and artificial joints. People who have repeated or chronic infections also usually need surgery. Surgery may simply involve cleaning the infected bone by scraping and irrigation, called debridement. In other cases, amputation, or removal of affected bones, may be the only alternative. Skin grafts may be needed for skin breakdown if a person has poor circulation to the area. Other treatments may also be needed in certain cases.

What are the side effects of the treatments?

Antibiotics may cause allergic reactions, stomach upset, or headaches. Specific side effects depend on the antibiotics used. Surgery carries a risk of bleeding and new infections. Reactions to pain medications may also occur.

What happens after treatment for the infection?

In some cases, the person is cured of the infection and needs no more treatment. In other cases, the infection becomes chronic, or comes back, and further treatment and monitoring are needed. The underlying cause, such as diabetes or poor circulation, may also need further treatment.

How is the infection monitored?

Symptoms, repeat exams, and repeat blood tests or x-rays may all be used to monitor this condition. Other monitoring is related to the cause. For example, those with diabetes need to check their blood sugar levels often.