Gout, repeated motion and overuse of a joint, certain vocations, injury, rheumatoid arthritis, spinal difficulties, and metabolic diseases such as diabetes are all risk factors for bursitis. Gout flares can cause inflammation of a bursa, most often the elbow bursa, resulting in gouty olecranon bursitis. This condition usually occurs after long-term exposure to high levels of uric acid or when treatment with allopurinol, a drug used to reduce the level of uric acid in blood, results in acute gout attacks. Bursae are fluid-filled sacks located between moving parts of joints to reduce friction. They are not true organs but instead act as shock absorbers. Bursae are found most commonly between bones and muscles that move relative to one another, including those of the shoulder, hip, knee, and elbow. There are three main types of bursae: gastrocnemius, subacromial, and iliotibial (or IT). Gastrocnemius bursae lie between the bone of the leg and the muscle tissue that bends over it; they are small and frequent sites of irritation caused by stone bruises or microfractures (tiny breaks) in the bone. The subacromial bursa is larger than the gastrocnemius bursa and lies beneath the acromion and the deltoid muscle.