What Causes Bursitis?

The term bursitis refers to inflammation and swelling of the bursa, a sac-like structure that forms under the skin to prevent two surfaces from rubbing together and causing damage. There are nearly 160 bursae in the body that cushion the joints and prevent bones, muscles and tendons rubbing together and causing friction related damage.

Bursitis refers to when a bursa becomes inflamed, usually through injury or repetitive movements. Athletes, for example, are more at risk of developing bursitis than the average person, as are gardeners or carpet fitters who repeatedly kneel in order to carry out their work. Bursitis can also be caused by infection or occur as a complication of other illnesses such as rheumatoid arthritis or gout.

Bursitis caused by injury

Injury and repetitive use of the joint is the most common cause of bursitis. This can irritate the tissue inside the bursa, leading to pain and inflammation. Bursitis can take a long time to develop and symptoms may only manifest after considerable overuse of the joint. Repetitive movement is therefore a particular risk for this type of injury.

Athletes, for example, are more at risk of developing bursitis than the average person, as are gardeners or carpet fitters who repeatedly kneel in order to carry out their work. Although any bursa can be affected, the condition usually involves the ankle, elbow, knee or hip. Sometimes referred to as “housemaid’s knee” or “clergyman’s knee,” bursitis in the knee may be caused by kneeling for extended periods while shoulder bursitis may affect javelin throwers or those who lift objects overhead for long periods.

Ankle bursitis is common among athletes, runners, walkers; hip bursitis may develop in those who sit on hard surfaces for prolonged periods; and the elbows are prone to bursitis in hockey players, athletes and dart players.

Bursitis caused by injury is more likely to occur as a result of chronic rather than acute joint injury.

Infections

Since bursae lie underneath the skin, they are prone to infection. Bacteria on the surface of the skin may gain entry to the bursa through cuts and grazes and this is referred to as septic bursitis. The clinical features associated with this condition include high fever, chills, shiver and cellulitis. The immune system usually prevents septic bursitis but individuals with a weakened immunity (e.g. the elderly, those with HIV infection, or people who have received chemotherapy) are at an increased risk of developing bursitis.

Inflammatory joint diseases

Several inflammatory joint diseases and other health conditions are also associated with an increased risk of bursitis. Examples include rheumatoid arthritis, gout, ankylosing spondylosis, systemic lupus erythematosus and scleroderma.