Bursitis

Acute or chronic inflammation of a bursa.

The causes include acute or chronic trauma, CPPD crystal deposition disease, and infection. Occasionally, bursae are involved in systemic inflammatory diseases such as rheumatoid arthritis.

Symptoms, Signs, and Diagnosis

Before treatment, the cause must be determined. If the history and physical examination do not yield obvious degeneration or trauma, the bursal fluid must be aspirated and examined for crystal deposits or infection. Aspiration and examination of subdeltoid or trochanteric bursae are rarely necessary before treatment unless signs of infection exist. A bursal fluid WBC count >= 2000/µL suggests an inflammatory process. The fluid should be examined microscopically for crystals, and a Gram stain should be performed to exclude infection.

Subdeltoid (subacromial) bursitis: The subdeltoid bursa is located between the deltoid muscle and the joint capsule, extending under the acromion and coracoacromial ligament. Subdeltoid bursitis results in painful shoulder movement, particularly abduction and extension. Patients with subdeltoid bursitis tend to awaken at night when they turn on the affected shoulder. The pain often radiates down the arm in the C-5 dermatome. Pain primarily over the anterior shoulder aggravated by forearm supination against resistance is more likely to reflect bicipital tendinitis.

Subdeltoid bursitis is the most common cause of nonarticular shoulder pain. It is often accompanied by inflammation of the supraspinatus tendon, and the two problems may be impossible to differentiate.

Physical examination reveals tenderness over the lateral shoulder and the subacromial space. Pain can be elicited if the arm is abducted and then actively moved toward the body against resistance. Patients report pain on moving the arm downward through the arc of abduction at about 90°.

Trochanteric bursitis: The trochanteric bursa lies between the gluteus maximus and the tendon of the gluteus medius. Trochanteric bursitis usually results in a dull, aching pain or a burning, tingling sensation over the lateral hip. The pain may also be referred to the L-2 dermatome. Pain is worse with activity and after sitting with the affected leg crossed over the other. Sleep disturbances and an inability to lie on the affected side are common.

Physical examination reveals localized tenderness over the bony prominence of the greater trochanter. External rotation with abduction of the hip is often painful, although the range of motion is normal.

Anserine bursitis: The anserine bursa is located about 4 cm (1.6 inches) below the medial aspect of the knee. It lies under the pes anserinus (the combined insertion of the tendinous expansions of the sartorius, gracilis, and semitendinous muscles). Anserine bursitis results in knee pain that is worse at night but may be improved by placement of a pillow between the knees.

Physical examination may reveal point tenderness over the bursa and, occasionally, mild to moderate swelling.

Olecranon bursitis: The bursa of olecranon lies between the skin and the olecranon process. Olecranon bursitis usually results in swelling and tenderness over the most proximal part of the ulna.

Physical examination reveals no tenderness or pain in the elbow, which exhibits full range of motion.

Treatment

If microcrystalline disease and infection are absent, the most successful treatment is fluid aspiration and injection of the bursal sac with a corticosteroid. Aspirin or another NSAID is also effective.

Infection is most commonly due to gram-positive organisms that colonize the skin: Staphylococcus aureus and group A streptococci. Antibiotics should be used; they may be given orally if the patient has no systemic symptoms (eg, high fever). An infected bursa should not be drained openly but repeatedly aspirated.

The patient should be encouraged to move the affected area, particularly the shoulder, but should avoid stressful exercise that may irritate it. Limited shoulder movement and frozen shoulder can become severe and long-term if range-of-motion exercises are neglected.