Osteomyelitis is an infection in a bone. Infections can reach a bone by traveling through the bloodstream or spreading from nearby tissue. It can also begin in the bone itself if an injury exposes the bone to germs.
In children, osteomyelitis most commonly affects the long bones of the legs and upper arm, while adults are more likely to develop osteomyelitis in the bones that make up the spine (vertebrae). People who have diabetes may develop osteomyelitis in their feet if they have foot ulcers.
Once considered an incurable condition, osteomyelitis can be successfully treated today. Most people require surgery to remove parts of the bone that have died — followed by strong antibiotics, often delivered intravenously, typically for at least six weeks.
Signs and symptoms of osteomyelitis include:
- Fever or chills.
- Irritability or lethargy in young children.
- Pain in the area of the infection.
- Swelling, warmth and redness over the area of the infection.
Sometimes osteomyelitis causes no signs and symptoms or has signs and symptoms that are difficult to distinguish from other problems.
Most cases of osteomyelitis are caused by staphylococcus bacteria, a type of germ commonly found on the skin or in the nose of even healthy individuals. Germs can enter a bone in a variety of ways, including:
- Via the bloodstream. Germs in other parts of your body — for example, from pneumonia or a urinary tract infection — can travel through your bloodstream to a weakened spot in a bone. In children, osteomyelitis most commonly occurs in the softer areas, called growth plates, at either end of the long bones of the arms and legs.
- Cross infection. Severe puncture wounds can carry germs deep inside your body. If such an injury becomes infected, the germs can spread into a nearby bone.
- Direct contamination. This may occur if you have broken a bone so severely that part of it is sticking out through your skin. Direct contamination can also occur during surgeries to replace joints or repair fractures.
Your bones are normally resistant to infection. For osteomyelitis to occur, a situation that makes your bones vulnerable must be present.
Recent injury or orthopedic surgery
A severe bone fracture or a deep puncture wound gives infections a route to enter your bone or nearby tissue. Surgery to repair broken bones or replace worn joints also can accidentally open a path for germs to enter a bone. Deep animal bites also can provide a pathway for infection.
When blood vessels are damaged or blocked, your body has trouble distributing the infection-fighting cells needed to keep a small infection from growing larger. What begins as a small cut can progress to a deep ulcer that may expose deep tissue and bone to infection. Diseases that impair blood circulation include:
- Poorly controlled diabetes
- Peripheral arterial disease, often related to smoking
- Sickle cell disease
Problems requiring intravenous lines or catheters
There are a number of conditions that require the use of medical tubing to connect the outside world with your internal organs. However, this tubing can also serve as a way for germs to get into your body, increasing your risk of an infection in general, which can lead to osteomyelitis. Examples of when this type of tubing might be used include:
- Dialysis machines
- Urinary catheters
- Long-term intravenous tubing, sometimes called central lines
Conditions that impair the immune system
If your immune system is affected by a medical condition or medication, you have a greater risk of osteomyelitis. Factors that may suppress your immune system include:
- Poorly controlled diabetes
- Having had an organ transplant
- Needing to take corticosteroids or drugs called tumor necrosis factor (TNF) inhibitors.
For unclear reasons, people with HIV/AIDS don't seem to have an increased risk of osteomyelitis.
People who inject illicit drugs are more likely to develop osteomyelitis because they typically use nonsterile needles.
- Bone death (osteonecrosis) An infection in your bone can impede blood circulation within the bone, leading to bone death. Your bone can heal after surgery to remove small sections of dead bone. If a large section of your bone has died, however, you may need to have that limb amputated to prevent spread of the infection.
- Septic arthritis In some cases, infection within bones can spread into a nearby joint.
- Impaired growth In children, the most common location for osteomyelitis is in the softer areas, called growth plates, at either end of the long bones of the arms and legs. Normal growth may be interrupted in infected bones.
- Skin cancer If your osteomyelitis has resulted in an open sore that is draining pus, the surrounding skin is at higher risk of developing squamous cell cancer.
Care and Treatment
If you've been told that you have an increased risk of infection, talk to your doctor about ways to prevent infections from occurring. Reducing your risk of infection will also reduce your risk of developing osteomyelitis. In general, take precautions to avoid cuts and scrapes, which give germs easy access to your body. If you do get any cuts and scrapes, clean the area immediately and apply a clean bandage. Check wounds frequently for signs of infection.