Bursae are fluid-filled sac-like cavities or potential cavities that are located where friction occurs (eg, where tendons or muscles pass over bony prominences). Bursae minimize friction between moving parts and facilitate movement. Some communicate with joints.
Bursitis may occur in the shoulder (subacromial or subdeltoid bursitis), particularly in patients with rotator cuff tendinitis Rotator Cuff Injury/Subacromial Bursitis Rotator cuff injury includes tendinitis and partial or complete tears; subacromial bursitis may result from tendinitis. Symptoms are shoulder area pain and, with severe tears, weakness. Diagnosis... read more , which is usually the primary lesion in the shoulder. Other commonly affected bursae include olecranon (miner's or barfly’s elbow), prepatellar (housemaid’s knee), suprapatellar, retrocalcaneal, iliopectineal (iliopsoas), ischial (weaver’s bottom), greater trochanteric, pes anserine, and first metatarsal head (bunion) bursae. Occasionally, a bursa ruptures or develops a chronic communication with an adjacent joint.
Etiology of Bursitis
Bursitis may be caused by the following:
Chronic overuse and/or pressure
Inflammatory arthritis (eg, gout Gout Gout is a disorder caused by hyperuricemia (serum urate > 6.8 mg/dL [> 0.4 mmol/L]) that results in the precipitation of monosodium urate crystals in and around joints, most often causing recurrent... read more , rheumatoid arthritis Rheumatoid Arthritis (RA) Rheumatoid arthritis is a chronic systemic autoimmune disease that primarily involves the joints. Rheumatoid arthritis causes damage mediated by cytokines, chemokines, and metalloproteases.... read more , psoriatic arthritis Psoriatic Arthritis Psoriatic arthritis is a seronegative spondyloarthropathy and chronic inflammatory arthritis that occurs in people with psoriasis of the skin or nails. The arthritis is often asymmetric, and... read more , spondylitis Ankylosing Spondylitis Ankylosing spondylitis is the prototypical spondyloarthropathy and a systemic disorder characterized by inflammation of the axial skeleton, large peripheral joints, and digits; nocturnal back... read more )
Acute or chronic infection (eg, Staphylococcus aureus in acute infections and mycobacteria in chronic infections)
Idiopathic and traumatic causes are by far the most common. Acute bursitis may follow unusual exercise or strain and usually causes bursal effusion. The olecranon and prepatellar bursae are the bursae most often involved when an infection is present.
Chronic bursitis may develop after previous attacks of bursitis or repeated trauma. The bursal wall is thickened, with proliferation of its synovial lining; bursal adhesions, villus formation, tags, and milky deposits may develop.
Symptoms and Signs of Bursitis
Acute bursitis causes pain, particularly when the bursa is compressed or stretched during motion, and often limits range of motion. Passive range of motion may still be normal (eg, some patients with olecranon bursitis have normal flexion-extension of the elbow). Swelling, sometimes with other signs of inflammation (eg, erythema), is common if the bursa is superficial (eg, prepatellar, olecranon). Swelling may be more prominent than pain in olecranon bursitis. Crystal- or bacterial-induced bursitis is usually accompanied by erythema, pitting edema, pain, and warmth in the area around the bursa.
Chronic bursitis may last for several months and may recur frequently. Bouts may last a few days to several weeks. If inflammation persists near a joint, the joint’s range of motion may be limited. Prolonged limitation of motion may lead to muscle atrophy.
Diagnosis of Bursitis
Ultrasonography or MRI for deep bursitis
Aspiration for suspected infection, hemorrhage (due to trauma or anticoagulants), or crystal-induced bursitis
Superficial bursitis should be suspected in patients with swelling or signs of inflammation over bursae. Deep bursitis is suspected in patients with unexplained pain worsened by motion in a location compatible with bursitis. Usually, bursitis can be diagnosed clinically. Ultrasonography or MRI can help confirm the diagnosis when deep bursae are not readily accessible for inspection, palpation, or aspiration. These tests are done to confirm a suspected diagnosis or exclude other possibilities. These imaging techniques increase the accuracy of identifying the involved structures.
If bursal swelling is particularly painful, red, or warm or if the olecranon or prepatellar bursa is affected, infection and crystal-induced disease Overview of Crystal-Induced Arthritides Arthritis can result from intra-articular deposition of crystals: Monosodium urate Calcium pyrophosphate dihydrate Basic calcium phosphate (apatite) Rarely, others such as calcium oxalate crystals read more should be excluded by bursal aspiration. After a local anesthetic is injected, fluid is withdrawn from the bursa using sterile techniques; analysis includes cell count, Gram stain and culture, and microscopic search for crystals. Gram stain, although helpful if positive, may not be specific, and white blood cell counts in infected bursae are usually lower than those in septic joints. Urate crystals are easily seen with polarized light microscopy, but the apatite crystals typical of calcific tendinitis appear only as shiny chunks that are not birefringent. Cholesterol plate crystals can be seen in chronic rheumatoid bursitis.
Acute bursitis should be distinguished from hemorrhage into a bursa, which should be considered particularly when a patient taking warfarin develops acute bursitis. Hemorrhagic bursitis can cause similar manifestations because blood is inflammatory. Fluid in traumatic bursitis is usually serosanguinous. Cellulitis Cellulitis Cellulitis is acute bacterial infection of the skin and subcutaneous tissue most often caused by streptococci or staphylococci. Symptoms and signs are pain, warmth, rapidly spreading erythema... read more can cause signs of inflammation but does not normally cause bursal effusion; cellulitis overlying the bursa is a relative contraindication to bursal puncture through the cellulitis, but if septic bursitis is strongly suspected, aspiration must be done.
Treatment of Bursitis
Rest followed by physical therapy
High-dose nonsteroidal anti-inflammatory drugs (NSAIDs)
Treatment of crystal-induced disease or infection
Sometimes, corticosteroid injection
For crystal-induced disease, see treatment of gout Treatment Gout is a disorder caused by hyperuricemia (serum urate > 6.8 mg/dL [> 0.4 mmol/L]) that results in the precipitation of monosodium urate crystals in and around joints, most often causing recurrent... read more and pseudogout Treatment Calcium pyrophosphate arthritis (CPP arthritis) involves intra-articular and/or extra-articular deposition of calcium pyrophosphate dihydrate (CPPD) crystals. Manifestations are protean and... read more .
For suspected infection, empiric antibiotics effective against S. aureus should be given initially (see treatment of staphylococcal infection Treatment Staphylococci are gram-positive aerobic organisms. Staphylococcus aureus is the most pathogenic; it typically causes skin infections and sometimes pneumonia, endocarditis, and osteomyelitis... read more ). Subsequent choice of antibiotic is determined by results of Gram stain and culture. Infectious bursitis requires drainage or occasionally excision in addition to antibiotics.
Acute nonseptic bursitis is treated with temporary rest or immobilization and high-dose NSAIDs Nonopioid Analgesics Nonopioid and opioid analgesics are the main drugs used to treat pain. Antidepressants, antiseizure drugs, and other central nervous system (CNS)–active drugs may also be used for chronic or... read more and sometimes with other analgesics. Physical therapy and voluntary movement should be increased as pain subsides. This may accelerate restoration of range of motion. Pendulum exercises are helpful for the shoulder joint.
In one study, corticosteroid injections relieved short-term (< 6 weeks) pain more than placebo (in patients with concurrent adhesive capsulitis), but they showed no benefit long term (1 Treatment reference Bursitis is acute or chronic inflammation of a bursa. The cause is usually unknown, but trauma, repetitive or acute, may contribute, as may infection and crystal-induced disease. Symptoms include... read more ). Corticosteroid injection should be considered if the bursal effusion is recurrent, infection has been excluded, and oral drugs and rest are inadequate. Aspiration and intrabursal injection of depot corticosteroids 0.5 to 1 mL (eg, triamcinolone acetonide 40 mg/mL) is the treatment of choice. About 1 mL of local anesthetic (eg, 2% lidocaine) can be injected before the corticosteroid injection. The same needle is used; it is kept in place and the syringes are changed. Dose and volume of the corticosteroid may vary according to the size of the bursa. Infrequently, a flare-up occurs within several hours of injection of a depot corticosteroid; the flare-up is probably a synovitis in reaction to crystals in the injection or to needle disruption of calcium deposits. It usually lasts ≤ 24 hours and responds to cold compresses plus analgesics. Oral corticosteroids (eg, prednisone) can be used to treat the primary problem if a local injection is not feasible.
Chronic bursitis is treated the same as acute bursitis, except that splinting and rest are less likely to help, and range-of-motion exercises are especially important. Rarely, the bursa needs to be excised.
1. Challoumas D, Biddle M, McLean M, et al: Comparison of treatments for frozen shoulder: A systematic review and meta-analysis. JAMA Netw Open. 3(12):e2029581, 2020. doi: 10.1001/jamanetworkopen.2020.29581. PMID: 33326025; PMCID: PMC7745103.
The usual causes of bursitis are injury and overuse, but infection and crystal-induced disease are possible.
Withdraw bursal fluid to diagnose bacterial or crystal-induced bursitis when the olecranon or prepatellar bursa is affected or when there is warmth, redness, tenderness, and pitting edema.
If no infection is present, treat most cases with rest, high-dose NSAIDs, and sometimes intrabursal corticosteroid injection.