Overview of Bursitis
Bursitis is inflammation of a fluid-filled sac (called a bursa; plural is bursae) located in the joints (where two bones or a bone and a tendon meet). Bursae contain synovial fluid, which lubricates the joints. They reduce friction between the bones and muscles, tendons, and ligaments.
Inflammation of a bursa results in pain, tenderness, and swelling. Bursitis commonly occurs in the shoulders, hips, elbows, knees, heels, and wrists. The condition sometimes can develop with tendonitis, which is inflammation of a tendon (fibrous tissue that connects muscle to bone).
Types of Bursitis
Bursitis can be acute (develop suddenly) or chronic (long-lasting). The condition can be classified according to the part of the body affected, or according to the cause (e.g., septic bursitis, which is caused by infection).
Common types of bursitis include the following:
- Achilles bursitis (affects the area where the Achilles tendon attaches to the heel bone)
- Anserine bursitis (also called gooselike bursitis; affects the knee and causes pain when climbing stairs)
- Iliopsoas bursitis (affects the hip and upper thigh)
- Ischial bursitis (develops as a result of prolonged periods of sitting and pivoting on hard surfaces; also called weaver's bottom)
- Olecranon bursitis (affects the back of the elbow)
- Prepatellar bursitis (develops as a result of kneeling on hard surfaces; also called housemaid's knee)
- Retrocalcaneal bursitis (affects the back of the heel)
- Subacromial bursitis (also called subdeltoid bursitis; develops in the shoulder as a result of repetitive overhead motion)
- Trochanteric bursitis (affects the hip and upper thigh)
Incidence & Prevalence of Bursitis
Bursitis is very common, even in people who are otherwise healthy. The condition can occur at any age and affects both men and women.
Bursitis Causes & Risk Factors
Common causes for acute bursitis include infection (called septic bursitis) and injury (trauma). Septic bursitis occurs when a bursa is infected by microorganisms, such as bacteria. This condition is more common in bursae that are close to the skin (e.g., those in the wrists and elbows).
Injury to a joint (e.g., falling onto the knees, bumping an elbow) can cause swelling (edema), resulting in acute bursitis. This type of trauma often causes severe pain and swelling.
Chronic bursitis can occur as a result of overuse or diseases and conditions, such as gout, rheumatoid arthritis, diabetes, and thyroid disease. Performing repetitive motions (e.g., typing, climbing stairs, running, biking, throwing a ball, swinging a tennis racquet, swimming) increases the risk for developing chronic bursitis. Over time, repetitive motions can cause minor injuries to the bursae that result in irritation and inflammation.
Other activities, such as kneeling or sitting on hard surfaces, regularly sleeping in one position for too long, or using improper body mechanics when lifting or reaching also can cause bursitis.