Osteomyelitis

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 it's 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 collection of pus).

Osteomyelitis is most common in the leg bones, but any bone can be affected. It can normally be treated with antibiotics and surgery, although it may come back in up to four out of 10 people.

In adults, osteomyelitis most commonly happens after an operation, particularly if something man-made, such as a metal hip, has been inserted, or if you have a compound fracture (when the broken end of the bone breaks through the skin). However, osteomyelitis can also result from bacteria in your blood getting into the bone when you have an infection somewhere else in your body, for example a tooth abscess, leg ulcer or even a throat infection. This is more common in children than in adults, but the reasons for this are not fully understood.

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 may not move the affected leg or arm)
• a fever and generally feel unwell
• pain or muscle spasms in your back, if your spine is affected
• pus at the site of the infection, for example where you had a broken bone

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

In adults, osteomyelitis usually develops a month after bacteria get into the bone, so you may have symptoms roughly a month after a broken bone or operation.

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 your 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 to your bones and lead to deformity or disability.

Septic arthritis

Osteomyelitis can sometimes cause septic arthritis – an infected joint. This happens if the pus caused by the infection leaks into a joint. If it’s not treated, your joint will be damaged and you won’t be able to move it fully.

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 and armpits of healthy people. Osteomyelitis can also be caused by other bacteria, or combinations of bacteria.

You’re more at risk of getting osteomyelitis if you:

• have broken a bone, especially a compound fracture
• have had bone surgery or joint replacement (such as a hip or knee replacement) or implant
• have had a bacterial infection somewhere else in your body – this cause is more common in babies and children
• have diabetes
• have poor circulation, for example peripheral vascular disease
• have a weakened immune system (for example, you’re having chemotherapy for cancer or you have HIV/AIDS)
• have sickle cell anaemia
• take steroids

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. He or she will refer you to an orthopaedic surgeon who may ask you to have a blood test.

Your 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 areas of bone in the body, where infection may be occurring

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 taking a swab of the area, blood tests or an operation where a small sample of your infected bone is taken (this is called a bone biopsy).

You will be given a general anaesthetic if you have a bone biopsy. This means you will be asleep during the operation and feel no pain. The biopsy will be sent to a laboratory for testing.

If you have a wound (for example, 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 usually need antibiotics for at least four to six weeks to clear the infection. The antibiotics will need to 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 go home and carry on taking your antibiotics as oral tablets. Some people need intravenous antibiotics for the whole course of treatment.

Infections that are resistant to treatment with common and widely available antibiotics (such as penicillin) are becoming more frequent. One type of resistant infection is called MRSA, which stands for methicillin-resistant Staphylococcus aureus. If you have osteomyelitis caused by MRSA, your doctors will need to use a different combination of antibiotics to treat the infection.

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’re 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 during the operation.

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 infected joint before you can have any other treatment. You will have another new joint put in once your infection has cleared.

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

For sources and links to further information, see Resources.