Osteomyelitis

Osteomyelitis is infection of bone, usually due to bacteria. The condition is most common in young children, but elderly people are also at risk. In other age groups, the condition is most common in people with reduced immunity, such as those with sickle-cell disease or diabetes mellitus. In young children, the vertebrae (spinal bones) or one of the long bones of the limbs are usually affected. In adults, osteomyelitis most commonly affects the vertebrae or the pelvis.


What are the causes?

There are two forms of osteomyelitis: one that comes on suddenly (acute), and the other that develops more gradually and is long-term (chronic).

The acute form of osteomyelitis is usually a consequence of infection with Staphylococcus aureus bacteria. These bacteria normally live harmlessly on the skin but they can enter the blood-stream and result in osteomyelitis if they infect the bone tissue as a result of a wound, fracture, joint replacement, or intravenous injection with a contaminated needle.

The chronic form of osteomyelitis may be caused by tuberculosis or in rare cases, by a fungal infection. In some cases, acute osteomyelitis may develop into the chronic form.

What are the symptoms?

The symptoms of acute osteomyelitis develop suddenly and may include:

- Swelling of the skin and severe pain in the affected area.
- Fever.
- In young children, not wanting to move an affected arm or leg.

Chronic osteomyelitis develops more slowly. Its symptoms include:

- Weight loss.
- Mild fever.
- Persistent pain in the affected bone. Pus may form in the bone and can make its way to the skin’s surface, causing a discharging opening (a sinus).

How is it diagnosed?

If your doctor suspects that you have osteomyelitis, he or she may arrange for X-rays, radionuclide scanning, or MRI to locate the infected area of bone. If pus is present, a sample may be aspirated (removed from the bone through a fine needle) for examination to identify the organism that is causing the disease.

What is the treatment?

Treatment will intravenous antibiotics is usually begun in hospital and may continue after you return home. You may then need to continue taking antibiotics orally for a period of several months. When osteomyelitis is caused by tuberculosis, anti-tuberculous drugs may be prescribed for a period of 12-18 months.

In some cases, surgery may be necessary to remove infected bone. If a large area of bone is removed, you may need a bone graft, in which the infected bone is replaced by new bone taken from else where in the body or from a donor. If the infection is associated with a joint replacement, the artificial joint will be removed, the infection treated, and a new joint put in its place.

The acute form of osteomyelitis is usually treated successfully, but the chronic form may take several months or years to clear up. In some cases, it may be necessary to take antibiotics indefinitely to suppress the infection.