Osteomyelitis

Published by Bupa's Health Information Team, April 2010.

This factsheet is for people who have osteomyelitis or who would like information about it.

Osteomyelitis is an infection of the bone, which can destroy the bone and cause deformity if not treated.

About osteomyelitis

Osteomyelitis is an infection of the bone and the bone marrow - the part of the bone where new blood cells are made. If it isn't treated, the infection gradually destroys the bone and can cause an abscess (a ball of pus).

In the past, osteomyelitis was a major cause of disability and even death. Nowadays, although it's serious, it can normally be treated and cured with a combination of antibiotics and surgery.

In adults, osteomyelitis most commonly happens after an operation, particularly if something man-made (such as a metal hip) has been inserted. However, osteomyelitis can also come on suddenly and for no apparent reason. This is more common in children than in adults.

Symptoms of osteomyelitis

If you have osteomyelitis, you may have:

• severe pain in the area where you have the infection
  
• swelling and a warm feeling in the affected area
  
• a feeling of being unable to move the limb where you have the infection (in children, this means the child will not move the affected leg or arm)
  
• a fever (sweating, especially at night) and a feeling of general illness
  
• pain or muscle spasm in your back, if your spine is affected

Although these symptoms aren't necessarily a result of osteomyelitis, if you have these symptoms, you should visit your GP.

If you have a chronic infection, you may also notice a discharge of pus at the location of your infection. If you have this symptom, you should see your GP.

Complications of osteomyelitis

Chronic osteomyelitis

When you first develop osteomyelitis, it's called acute osteomyelitis. An acute illness is typically over quite quickly. When describing an illness, the term 'acute' refers to how long a person has had it, not to how serious the condition is.

If the infection isn't treated properly or quickly enough, part of the bone can die. The infection can become more serious and may go on for several months or even years. This is called chronic osteomyelitis. A chronic illness is one that lasts a long time, sometimes for the rest of the affected person's life. Chronic osteomyelitis may cause flare-ups of symptoms, such as pain and fever, many years after the initial infection.

When an infection lasts for such a long time, it can cause severe damage and possible deformity of your bones.

MRSA and osteomyelitis

Infections that are resistant to treatment with the common and widely available antibiotics (such as penicillin) are becoming more frequent. This type of infection is called MRSA, which stands for meticillin-resistant Staphylococcus aureus. If you have osteomyelitis caused by MRSA, it means that your infection will be difficult to treat and you may need treatment with a combination of various medicines.

Septic arthritis

Osteomyelitis can sometimes develop into a condition called septic arthritis. This happens if the pus caused by the infection discharges into a joint, rather than coming out through your skin. If untreated, your joint will become infected and damaged, which will limit its movement.

Causes of osteomyelitis

Osteomyelitis is normally caused by bacteria called Staphylococcus aureus. This type of bacteria is quite common, for example it can live in the noses of healthy people. Osteomyelitis can also be caused by other bacteria, or combinations of bacteria.

You may be more at risk of getting osteomyelitis if you fall into one of the following groups.

• You have broken a bone or have had surgery involving a bone.
  
• You have had a joint replacement (such as a hip or knee replacement).
  
• You have had an infection somewhere else in your body. The infection then spreads to your bone through your bloodstream. This happens most often in children and the elderly.
  
• You have diabetes - you will be at an increased risk of getting an infection in your feet, which may then spread to your bone.
  
• You have a weakened immune system (for example, if you are having chemotherapy for the treatment of cancer or if you have HIV).

Diagnosis of osteomyelitis

You may already be in hospital when you get osteomyelitis. For instance, you might be recovering from surgery or having treatment for a broken bone. An orthopaedic surgeon (a doctor specialising in bone surgery) at the hospital will carry out tests to check whether osteomyelitis is causing your symptoms.

If your GP thinks that you might have osteomyelitis he or she will ask you about your symptoms and examine you. Your GP may also ask you about your medical history and do a blood test. He or she will refer you to an orthopaedic surgeon.

Imaging tests

The orthopaedic surgeon will confirm whether you have osteomyelitis by taking images of your bones. This may include having:

• an X-ray - although X-ray images don't always show problems in the early stages of the infection
  
• an MRI (magnetic resonance imaging) scan - this uses magnets and radiowaves to produce images of the inside of your body
  
• a CT (computerised tomography) scan - this uses X-rays to make a three-dimensional picture of the body or part of the body
  
• a bone scan - this shows active areas of bone in the body, where infection may be occurring

Bacteria tests

Your surgeon will also do some tests to find out the exact type of bacteria that is causing your infection. This is important in order to work out which treatment is best for you. These tests may involve blood tests or an operation where a small sample of your infected bone is taken (this is called a bone biopsy).

Your surgeon will give you an anaesthetic if you have a bone biopsy. This may be a general anaesthetic, which means you will be asleep during the operation and feel no pain. Or it may be a local anaesthetic that completely blocks feeling from the infected area, but you will be awake during the operation. The biopsy will be sent to a laboratory for testing.

If you have a wound (eg following an injury or operation), your doctor or surgeon may take a swab from the wound, which will be sent to a laboratory. The laboratory will investigate which bacteria are causing your infection, and decide whether it can be treated with an antibiotic.

Treatment of osteomyelitis

Medicines

You will need antibiotics for at least four to six weeks to get rid of the infection. The antibiotics will often be given to you intravenously (into your vein) at first, while you stay in hospital. If your symptoms have started to improve after this, you may be able to carry on taking your antibiotics by mouth, at home. Some people need intravenous antibiotics for the whole course of treatment.

Surgery

You may need surgery as well as treatment with antibiotics. Surgery can remove dead or infected bone, and drain away pus that has built up in your bone. You are more likely to need this surgery if you have chronic or severe osteomyelitis. You will be given either a general or local anaesthetic, so you won't feel any pain.

If a lot of your bone has to be removed, you may also need to have a bone graft. This means that bone is taken from one of your other, uninfected, bones (usually your iliac bone, just above your hip) to replace the bone that has been destroyed. You may also need plastic surgery to cover the damaged skin and tissue with healthy tissue.

If your infection has been caused by a joint replacement, your surgeon will normally have to remove the new joint before you can have any other treatment. You will have another new joint put in once your infection has gone.

For answers to frequently asked questions on this topic, see Common questions.

For sources and links to further information, see Resources.