bursitis

Bursitis is inflammation of a bursa, a small fluid-filled sac that cushions bones, tendons, and muscles near joints. Bursae reduce friction and allow smooth movement. The condition most commonly affects the shoulder, elbow, hip, and knee, but can occur at any joint.

Causes include repetitive motion, prolonged pressure, or a sudden injury, leading to noninfectious bursitis. Infections can cause septic bursitis, typically by bacteria such as Staphylococcus aureus, and require urgent treatment. Chronic bursitis may be related to inflammatory conditions like rheumatoid arthritis or gout.

Symptoms include localized swelling, warmth, redness, pain with movement or pressure, and restricted joint motion. Fever or malaise may occur with septic bursitis.

Diagnosis involves clinical exam and history; tests may include ultrasound or MRI to assess the bursa. Aspiration of bursal fluid can help distinguish infection from inflammatory causes and analyze cell counts, crystals, or culture. Blood tests may support evaluation for infection or inflammatory disease.

Treatment depends on the cause. Noninfectious bursitis often improves with rest, ice, compression, elevation, and nonsteroidal anti-inflammatory drugs or analgesics. Persistent or symptomatic cases may benefit from aspiration to remove fluid or a corticosteroid injection if infection is not suspected; physical therapy can restore movement. Septic bursitis requires antibiotics and sometimes surgical drainage.

Prognosis is generally good with appropriate treatment, though bursitis can recur. Prevention includes avoiding prolonged kneeling or pressure on joints, using padding or supportive devices, gradual increases in activity, and management of underlying conditions.