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Infectious Arthritis

Alternative names: Bacterial Arthritis, Fungal Arthritis, Mycobacterial Arthritis, Septic Arthritis, Non-Gonococcal/Gonococcal Infectious Arthritis, Pyogenic Arthritis

What is infectious arthritis?

Arthritis is a condition that causes inflammation of the joints and breakdown of cartilage. This kind of arthritis is caused by a germ, such as a fungus, bacterium, or virus. It may occur after there has been an infection in another area of the body and it generally only affects one joint at a time. The most commonly affected joints are the larger ones, including hips, knees, and shoulders.

Although anyone can be affected by infectious arthritis, the following individuals have an increased risk of getting the condition:

  • People who handle animals, soil, and plants frequently
  • People who have a condition that makes it difficult to fight infections (AIDS, immune deficiency, diabetes, sickle-cell anaemia)
  • People who already have arthritis in a joint

What are the signs of infectious arthritis?

The signs of infectious arthritis depend on the type of germ that infects the body. Sometimes the pain can be all over the body and in other cases, the pain will be in just one joint. Pain may be accompanied with fever and chills.

What causes infectious arthritis?

A joint may become infected when a germ enters the body. The germ can travel through the bloodstream and settle in a joint. Your immune system will try to fight off this germ. This will result in inflammation and swelling in the joint.

Bacteria are one of the most common causes of infectious arthritis. These may include bacteria that also cause Lyme Disease, some sexually transmitted diseases, and tuberculosis. Fungus found in some soil, plants and animals can also cause infectious arthritis. Viruses, such as parvovirus (or fifth disease) and mumps can also cause inflammation of the joints.

Infectious arthritis is not contagious but the germ that causes infectious arthritis may be spread from person to person. However, a person who is infected by the germ that caused another person to have infectious arthritis, may not develop infectious arthritis.

How does my doctor tell if I have infectious arthritis?

No single test can diagnose infectious arthritis. Most doctors use a combination of the following methods to identify the disease and rule out other conditions:

  • Clinical history: The doctor may begin by asking the patient to describe the symptoms, and when and how the condition started. Good doctor-patient communication is important. The doctor can understand the patient's problem better if the patient gives a good description of pain, stiffness, and joint function, and how they have changed over time. It also is important for the doctor to know how the problem affects the patient's work and daily life. The doctor may also ask you questions about your recent activities, such as trips you have taken, recent illnesses, or contact with sick people. Finally, the doctor also needs to know about other medical problems and whether the patient is taking any medicines.
  • Physical examination: The doctor may check the patient's general health, including checking reflexes and muscle strength. Joints bothering the patient will be examined. The doctor will also observe the patient's ability to walk, bend, and carry out activities of daily living.
  • Laboratory tests: If an infection is suspected, the doctor may take blood or fluid for testing. Fluid may be drawn from the affected joint using a needle. If tuberculosis or a fungus is suspected of causing the disease then a small piece of tissue in the affected joint may need to be removed for examination. Other tests may also be required to identify the germ causing the inflammation. Laboratory testing is used to confirm that the inflammation is caused by a germ and to identify the exact type of germ.
  • X-rays: Doctors may request X-rays in order to rule out other possible causes of the joint inflammation such as osteoarthritis, if indicated.

How is infectious arthritis treated?

It is important to treat infectious arthritis as early as possible. If it is left untreated it may damage the cartilage in the joint and the infection can spread to other parts of the body. If treated in good time, infectious arthritis is generally not a long-term condition.

Most patients will be treated in the hospital for the first several days until the infection is under control. After the initial stay there may be follow-up medication required for several weeks or months.

If necessary, the doctor may drain the joint each day or several times a day. Periodic laboratory tests will also be taken to test whether the germ is still in the body.

Non-surgical treatments

Medicines: Doctors may prescribe medicines to fight against the infection and to get rid of or reduce pain. Doctors consider a number of factors when choosing medicines for their patients with infectious arthritis. Two important factors are how bad the pain is and the possible side effects of the medicine. Patients must use medicines carefully and tell their doctors about any changes that occur.

The following types of medicines are commonly used in treating infectious arthritis:

  • Antibiotics help your body fight against germs. They are usually given to patients who have infectious arthritis caused by bacteria. The kind of antibiotic prescribed will depend on the type of germ. Antibiotics may be taken orally (through the mouth) or intravenously (through a vein). Generally, patients need to take antibiotics intravenously in the hospital for the first several days. It is very important to take the full amount of antibiotics prescribed even if the symptoms have gone away. If you don't take the full amount the bacteria can get stronger and build up a defense against future antibiotics.
  • Acetaminophen, a pain reliever such as Tylenol*, which does not reduce inflammation does not irritate the stomach and is less likely than nonsteroidal anti-inflammatory drugs (NSAIDs) to cause long-term side effects.
  • NSAIDs (nonsteroidal anti-inflammatory drugs), some over-the-counter medications such as aspirin, Advil*, Motrin IB*, Aleve*, ketoprofen, and other, prescription medicines
  • COX-2 inhibitors, new NSAIDs such as celecoxi and Celebrex* reduce inflammation.

* Brand names included here are provided as examples only. Their inclusion does not mean they are endorsed by Dartmouth-Hitchcock. Also, if a certain brand name is not mentioned, this does not mean or imply that the product is unsatisfactory

Many medicines used to treat infectious arthritis have side effects, so it is important for people to learn about the medicines they take. Even nonprescription drugs should be checked. Several groups of patients are at high risk for side effects from NSAIDs, such as people with a history of peptic ulcers or digestive tract bleeding, people taking oral corticosteroids or anticoagulants (blood thinners), smokers, and people who consume alcohol. Some patients may be able to help reduce side effects by taking some medicines with food. Others should avoid stomach irritants such as alcohol, tobacco, and caffeine. Some patients try to protect their stomachs by taking other medicines that coat the stomach or block stomach acids. These measures help, but they are not always completely effective.

Non-drug pain relief: People with infectious arthritis may find ways to relieve pain without drugs or medicines. Warm towels, hot packs, or a warm bath or shower to apply moist heat to the joint can relieve pain and stiffness. In some cases, cold packs (a bag of ice or frozen vegetables wrapped in a towel) can relieve pain or numb the sore area. (Check with a doctor or physical therapist to find out if heat or cold is the best treatment.) Water therapy in a heated pool or whirlpool also may relieve pain and stiffness. For infectious arthritis in the knee, patients may wear insoles or cushioned shoes to redistribute weight and reduce joint stress.

Exercise: Exercises after infection is under control can help to strengthen muscles and increase the range of motion. The doctor may prescribe an exercise program for you. It is important to always ask your doctor before starting any exercise that affects the area.

Surgical treatments

Depending on the severity of the swelling in the affected joint, the joint may need to be drained of fluid surgically. Surgical drainage of the joint may be required for individuals who do not respond well to medication or have infection in joints that are difficult to reach.

In some cases infectious arthritis damages the joint and requires reconstructive surgery. Reconstructive surgery can only happen after the infection has been treated.

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