Bursitis is an inflammation of a bursa, which is a fluid-filled sac located near the bones around the joints and between muscle attachments at a joint. They cushion and lubricate the movement of tendons and muscle over bone. Bursitis is not arthritis; arthritis is a change within the joint and bursae are outside of the joint.
The joint most commonly affected with bursitis is the shoulder. Other joints that may develop bursitis include the elbow, the knee (this is also known as housemaid's knee), the hip, and the base of the big toe (part of what is called a bunion). Bursitis may be acute or chronic. With the chronic form, symptoms of pain and swelling tend to come and go over cycles of weeks or months.
Bursitis can start in four different ways:
Trauma or injury: Ordinarily, a muscle-pull shouldn't affect a bursa. An injury that causes deep bruising, however, could provoke a brief inflammation of a bursa. This will often clear up without treatment.
Overuse: Many forms of bursitis have nicknames like "housemaid's knee," "miner's elbow," and even "tailor's bottom." Inflammation can result from repetitive strain placed on a joint, or continual pressure on the bursa itself (e.g., by kneeling).
Inflammatory arthritic disease: Conditions like rheumatoid arthritis and gout can lead to the release of inflammatory agents into the bursae. Also, calcium-based crystals can form in the sacs, causing friction and tearing.
Infection: Many common bacteria can infect the bursae.
Symptoms and Complications
The essential symptom of bursitis is pain that is localised near the joint, often accompanied by redness, stiffness, tenderness, and swelling. The pain is likely to be worse when you make unaccustomed movements or strain the joint muscles. Many other diseases can cause joint pain, so it's important that you see a health care professional for a proper diagnosis. Very red, hot skin and extreme pain is often a sign of either crystal-induced arthritis or a bacterial infection.
Severe or long-lasting bursitis of the shoulder, for example, can lead to reduced movement or use of the joint and result in muscle atrophy (wasting). Permanent changes in the shape of the bursa, such as thickening or enlarging can occur and the surrounding tissues can become chronically inflamed.
Making the Diagnosis
Before making a diagnosis of bursitis, a number of possibilities need to be ruled out. Muscle injuries, joint injuries, local internal bleeding, synovitis (inflammation within the joint), and cellulitis (skin infection) can all cause bursitis-like symptoms. Your doctor may ask you to take tests for rheumatoid arthritis and osteoarthritis.
If the joint is hot, red, and swollen, your doctor will want to check for bacteria. It's vital to know if the bursa is infected, because the standard treatment for noninfectious bursitis does not treat infection and in some situations may suppress the immune system.
Treatment and Prevention
A mild bout of bursitis that is not caused by bacteria is usually treated with rest or a splint, ice packs, acetylsalicylic acid* (ASA), or other anti-inflammatory medications. Physiotherapy treatments like ultrasound may be helpful.
If these treatments don't work you may be given an injection of corticosteroids mixed with local anesthesia. These medications are injected directly into the bursa. The injection can cause local side effects, such as acute reaction, infection, and bleeding. The injection usually causes fewer, if any, of the side effects that can occur from corticosteroids taken by mouth.
Corticosteroids are potent anti-inflammatories that usually reduce the inflammation, though often only temporarily. If corticosteroid injections don't help, the same medication might be given in pill form. It’s important to discuss the benefits and risks of corticosteroids taken by mouth because of the more serious risks of side effects from oral corticosteroids. Corticosteroids are never given to people with bacterial infections, which are treated with antibiotics.
Sometimes your doctor will draw some fluid out with a needle to see if there are signs of more serious disease. The fluid usually reappears.
When you are recovering from bursitis, it’s important to exercise the joint’s full range of motion so that you do not end up with a contracted joint. Your doctor or therapist will give you a detailed plan, depending on which joint is used and the amount of muscle loss. Physiotherapy and ultrasound are other types of treatment your doctor may suggest.
*All medications have both common (generic) and brand names. The brand name is what a specific manufacturer calls the product (e.g., Tylenol®). The common name is the medical name for the medication (e.g., acetaminophen). A medication may have many brand names, but only one common name. This article lists medications by their common names. For information on a given medication, check our Drug Information database. For more information on brand names, speak with your doctor or pharmacist.