Infectious arthritis is joint pain, soreness, stiffness and swelling caused by an infection by bacteria, viruses or fungi.

These infections can enter a joint various ways:

• After spreading through the bloodstream from another part of the body, such as the lungs during pneumonia
• Through a nearby wound
• After surgery, an injection or trauma, such as an insect bite

Once the infection reaches the joint, it can cause symptoms of joint inflammation and, at times, fever and chills. Depending on the type of infection, one or more joints may be affected.

The most common joint affected by bacterial infection is the knee. Small joints, such as those in fingers and toes, are more likely to become infected after a viral infection or direct injury, such as a bite. In people who use intravenous drugs, joints in the spine or breastbone (sternum) may be involved. People who already have rheumatoid arthritis or another joint disease are more likely to develop infectious arthritis.

Certain bacteria can cause a form of infectious arthritis called reactive arthritis (formerly called Reiter's disease), which appears to be caused by the immune system reacting to bacteria, rather than by the infection itself. In reactive arthritis, joint inflammation develops weeks, months or even years after the infection. Reactive arthritis happens most commonly after infections of the genital and gastrointestinal tracts.

Symptoms of infectious arthritis include:

• Joint pain and stiffness, typically in the knee, shoulder, ankle, finger, wrist or hip
• Warmth and redness around the joint
• Fever and shaking chills
• Skin rash

Other symptoms vary, depending on the cause. Some more common causes of infectious arthritis include:

Lyme Disease
Lyme disease is caused by bacteria that live in deer ticks and are transmitted through a tick bite into a person's bloodstream.

Because the tick bite often goes unnoticed and the rash may be overlooked, Lyme disease is not always diagnosed immediately. When the infection is not treated, further symptoms may develop, including joint inflammation (most commonly in the knee). Arthritis typically develops in the later stages of Lyme disease.

Gonorrhea
Gonorrhea is a sexually transmitted bacterial infection that can cause pain in one or more joints or tendons and sometimes a rash and fever. About one-third of people with gonorrhea report joint pain.

Staphylococcus Infection
Staphylococcus bacteria are common bacteria that can cause infections through cuts or other breaks in the skin, or through contaminated food. The bacteria can be released in the bloodstream and spread to the knee or other joints, causing intense and sudden pain, swelling and immobility of the joint. This is a serious condition because joint damage can develop within days if the infection is not found and treated quickly.

Tuberculosis
Tuberculosis is an infection caused by the Mycobacterium tuberculosis bacterium. It usually affects the lungs, but it can affect other parts of the body, including the gastrointestinal tract, nerves, lymph system and skin, as well as bones and joints. Arthritis caused by tuberculosis usually affects either the spine or large joints, such as the hips or knees. The joint inflammation caused by tuberculosis tends to be less dramatic than inflammation caused by some other bacterial infections, and it develops slowly.

Viruses
Arthritis can be caused from infection by many viruses, including those that cause colds, upper respiratory infections, human immunodeficiency virus (HIV), hepatitis, parvovirus, rubella and mumps. Many joints can be affected at the same time, and the symptoms of viral infectious arthritis can be similar to the symptoms of rheumatoid arthritis. However, viral arthritis symptoms usually disappear within days or weeks if the disease causing the problem goes away. HIV and some forms of viral hepatitis may cause chronic (long-lasting) infection and longer-lasting joint symptoms.

If your doctor suspects that your joint symptoms are related to a bacterial infection, he or she probably will remove fluid from the affected joint with a needle and will have it analyzed in a lab. You may have blood and urine tests. If your doctor thinks a sexually transmitted disease may be causing the problem, he or she will do a pelvic examination if you are a woman and a swab of the penis and a urine test if you are a man. The urine and swabbed material are sent to be tested in a laboratory. Tests are not available to diagnose most viral diseases. However, the more serious viral diseases, such as parvovirus, hepatitis B, hepatitis C and HIV, can usually be diagnosed with blood tests.

How long symptoms last depends on the cause and how soon treatment is started. Symptoms can improve as soon as 24 hours after treatment starts. However, they may continue for weeks or months when related to Lyme disease, many bacterial strains or tuberculosis. If infection damages joints, symptoms may last a lifetime.

The best way to prevent infectious arthritis varies depending on the type of infection:

• Staphylococcal arthritis � If you have a staphylococcal infection, antibiotics can be used to prevent this type of arthritis. However, for many people, joint pain and swelling are the first signs of the infection.



• Gonococcal arthritis � You can prevent this type of arthritis by preventing gonorrhea. Practice safe sex or don't have sex.



• Lyme disease arthritis � The best way to prevent arthritis from a Lyme infection is to avoid Lyme disease. Wear long pants and long-sleeved shirts, use tick repellent, and avoid woods, brush and other areas where ticks live. If you live in an area where Lyme disease is common, you can prevent Lyme infection by taking antibiotics soon after finding an attached or engorged deer tick. Similarly, you can prevent Lyme arthritis by taking antibiotics when the rash of Lyme disease is first observed.



• Tuberculosis-related arthritis � A tuberculosis vaccine may help to prevent tuberculosis and any associated arthritis. However, vaccination for tuberculosis is not routine in many parts of the world, including the United States, and the vaccine is only moderately effective. If you have tuberculosis, antibiotics may prevent joint infection and arthritis. If a skin test shows recent exposure to tuberculosis or if a chest X-ray suggests active tuberculosis, antibiotics may stop the infection from spreading into joints.



• Viral arthritis � The best way to avoid arthritis caused by a viral infection is to avoid getting the infection. Wash your hands after you have been around sick children or other people with a viral infection. Ways to prevent hepatitis B, hepatitis C and HIV include avoiding use of injected drugs and not having unprotected sex with a person who may be infected (see links above for more detailed information).

Because many bacterial infections can permanently destroy cartilage around joints, a joint infected with bacteria needs to be treated immediately with antibiotics.

Viral infections do not respond to antibiotics and most will go away on their own. However, antiviral therapies are available for some viral infections, such as hepatitis C and HIV. Aspirin or ibuprofen (Advil, Motrin and other brand names) can be taken to alleviate pain and swelling during the time it takes for the infection to go away. Viral infections usually do not cause joint damage.

If you have a bacterial infection, you probably will be hospitalized so the infected joint can be drained, you can receive antibiotics intravenously (into a vein) and you can rest the joint.

In some cases, surgery may be necessary to remove damaged tissue from the joint. If serious damage already has occurred, surgery may be needed to reconstruct the joint. Surgery is rarely necessary for arthritis associated with gonorrhea or viral infection.

Reactive arthritis may be treated with other medicines, but only after the infection has been cured. These medicines include nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, methotrexate (Folex, Methotrexate LPF, Rheumatrex) and sulfasalazine (Azulfidine).

While the joint is recovering from the infection, it may need to be immobilized briefly with a brace or splint. As soon as possible, however, exercise and physical therapy are recommended to restore strength and mobility.

If you experience any of the symptoms of infectious arthritis for more than a few days, contact your doctor.

If infectious arthritis is detected and treated promptly, joint damage is unlikely. However, joint damage is possible with many types of infections, especially when a bacterial infection is not diagnosed and treated promptly.

American College of Rheumatology
1800 Century Place
Suite 250
Atlanta, GA 30345-4300
Phone: 404-633-3777
Fax: 404-633-1870
http://www.rheumatology.org/

Arthritis Foundation
P.O. Box 7669
Atlanta, GA 30357-0669
Phone: 404-872-7100
Toll-Free: 1-800-283-7800
http://www.arthritis.org/