Bursitis

Bursitis is painful inflammation of a bursa (a flat sac containing joint [synovial] fluid that reduces friction in areas where skin, muscles, tendons, and ligaments rub over bones).

A bursa normally contains very little fluid. If injured or overused, however, the bursa may become inflamed and fill with fluid.

Bursitis is usually caused by irritation from unusual uses or overuses. It may also be caused by injury, gout, pseudogout, rheumatoid arthritis, or certain infections, especially those caused by Staphylococcus aureus; often, the cause is unknown. Although the shoulder is most susceptible to bursitis, bursas in the elbows, hips (trochanteric bursitis), pelvis, knees, toes, and heels (Achilles tendon bursitis (see Section 5, Chapter 72)) commonly become inflamed.

Symptoms

Bursitis causes pain and tends to limit movement, but the specific symptoms depend on the location of the inflamed bursa. For example, when a bursa in the shoulder becomes inflamed, raising the arm out from the side of the body (as when putting on a jacket) is painful and difficult.

Acute bursitis occurs suddenly. The inflamed area is painful when moved or touched. The skin over bursas located close to the surface, such as near the knee and elbow, may appear red and swollen. Acute bursitis caused by an infection or gout (see Section 5, Chapter 70) is particularly painful, and the affected area is red and feels warm when touched.

Chronic bursitis may result from previous bouts of acute bursitis or repeated injuries. In some cases, the walls of the bursa thicken, and abnormal material with solid, chalky calcium deposits may accumulate. Damaged bursas are susceptible to additional inflammation when subjected to unusual exercise or strain. Long-standing pain and swelling can limit movement, causing muscles to waste away (atrophy) and become weak. Flare-ups of chronic bursitis may last a few days to several weeks and frequently recur.

Diagnosis and Treatment

A doctor suspects bursitis if the area around a bursa is sore when touched and specific joint movements are painful. If the bursa is noticeably swollen, the doctor may remove a sample of fluid from the bursa with a needle to test for causes of the inflammation, such as an infection or gout. X-rays are usually not helpful; however, they may be able to detect the calcium deposits of chronic bursitis.

Acute bursitis not caused by an infection is usually treated with rest, temporary immobilization of the affected joint, ice applied to the painful area, and a nonsteroidal anti-inflammatory drug (NSAID) (see Section 6, Chapter 78). Occasionally, stronger analgesics (such as an opioid) are needed. Often, when the bursa is not infected, a doctor may inject a mixture of a local anesthetic and a corticosteroid directly into the bursa. This treatment provides relief immediately or within a few hours to days. The injection may have to be repeated after a few months.

People who have severe acute bursitis may occasionally be given a corticosteroid, such as prednisone, by mouth for a few days. As the pain subsides, the person can perform specific exercises to increase the joint's range of motion.

Chronic, noninfected bursitis is treated in a similar way, although rest and immobilization are less likely to help. Rarely, when large calcium deposits occur in the shoulder, they may be irrigated through a wide-gauge needle (after being loosened, the sediment can be drawn out through the needle). This procedure may be performed in the doctor's office. Large deposits may need to be removed surgically.

Disabling bursitis in the shoulder may be relieved by several repeated injections of corticosteroids along with intensive physical therapy to restore the joint's function. Exercises can help strengthen weakened muscles and reestablish the joint's full range of motion. Bursitis often recurs if the underlying cause, such as gout, rheumatoid arthritis, or chronic overuse, is not corrected.

Infected bursas must be drained, and appropriate antibiotics given, often against Staphylococcus aureus.