Common Superficial Bursitis

MORTEZA KHODAEE

MORTEZA KHODAEE, MD, MPH

Am Fam Physician. 2017;95(4):224-231

Patient information: See related handout on bursitis of the elbow, knee, and heel, written by the author of this article.

Author disclosure: No relevant financial affiliations.

Superficial bursitis most often occurs in the olecranon and prepatellar bursae. Less common locations are the superficial infrapatellar and subcutaneous (superficial) calcaneal bursae. Chronic microtrauma (e.g., kneeling on the prepatellar bursa) is the most common cause of superficial bursitis. Other causes include acute trauma/hemorrhage, inflammatory disorders such as gout or rheumatoid arthritis, and infection (septic bursitis). Diagnosis is usually based on clinical presentation, with a particular focus on signs of septic bursitis. Ultrasonography can help distinguish bursitis from cellulitis. Blood testing (white blood cell count, inflammatory markers) and magnetic resonance imaging can help distinguish infectious from noninfectious causes. If infection is suspected, bursal aspiration should be performed and fluid examined using Gram stain, crystal analysis, glucose measurement, blood cell count, and culture. Management depends on the type of bursitis. Acute traumatic/hemorrhagic bursitis is treated conservatively with ice, elevation, rest, and analgesics; aspiration may shorten the duration of symptoms. Chronic microtraumatic bursitis should be treated conservatively, and the underlying cause addressed. Bursal aspiration of microtraumatic bursitis is generally not recommended because of the risk of iatrogenic septic bursitis. Although intrabursal corticosteroid injections are sometimes used to treat microtraumatic bursitis, high-quality evidence demonstrating any benefit is unavailable. Chronic inflammatory bursitis (e.g., gout, rheumatoid arthritis) is treated by addressing the underlying condition, and intrabursal corticosteroid injections are often used. For septic bursitis, antibiotics effective against Staphylococcus aureus are generally the initial treatment, with surgery reserved for bursitis not responsive to antibiotics or for recurrent cases. Outpatient antibiotics may be considered in those who are not acutely ill; patients who are acutely ill should be hospitalized and treated with intravenous antibiotics.

A bursa is a fluid-filled synovial pouch that can be deep or superficial and functions as a cushion to reduce friction between structures such as tendons, bone, or skin.¹ Superficial bursae are located in the subcutaneous tissue between bone and overlying skin. There are many superficial bursae in the body, but only olecranon, prepatellar, superficial infrapatellar, and subcutaneous (superficial) calcaneal bursitis have been reported. Historically, enlargement of a bursa has been called bursitis, although in many cases no true inflammatory process exists.² This article reviews the causes, locations, presentation, diagnosis, and management of superficial bursitis.

Clinical recommendation	Evidence rating	References
Bursal aspiration with fluid analysis should be performed in patients with suspected septic superficial bursitis.	C	³, ⁴, ⁸, ⁹, ¹⁶, ¹⁷, ^30–32
Initial management of superficial bursitis caused by microtrauma should consist of conservative measures such as padding, ice, elevation, and analgesics (only for pain).	B	^3–5, ⁸, ⁹, ²¹, ³⁵, ³⁹
Septic superficial bursitis should be treated empirically with systemic antibiotics covering Staphylococcus aureus and Streptococcus pyogenes. The antibiotic regimen can be modified, if needed, after culture andsensitivity results from the aspirated bursal fluid are available.	B	³, ⁴, ⁸, ⁹, ^16–19, ³⁰, ³⁵, ⁴⁸, ⁴⁹

Causes and Locations

Superficial bursitis is broadly classified as acute traumatic/hemorrhagic, chronic aseptic (due to microtraumatic or inflammatory causes), or septic (Table 1).

		Major risk factors
Location	Prevalence	Occupation, type of athlete, and other contributors	Body positions	Most common pathophysiologic mechanism	Other pathophysiologic mechanisms
Olecranon	Common	Miners, students, draftsmen, plumbers, heating and air conditioning technicians	Leaning on elbows	Chronic microtraumatic	Traumatic/hemorrhagic, aseptic inflammatory, septic
Olecranon	Common	Chronic hemodialysis	Leaning on elbows	Chronic microtraumatic	Traumatic/hemorrhagic, aseptic inflammatory, septic
Prepatellar	Relatively common	Coal miners, carpet layers, housemaids, plumbers, concrete finishers, roofers, wrestlers	Kneeling and crawling	Chronic microtraumatic	Traumatic/hemorrhagic, septic
Superficial infrapatellar/pretibial	Rare	Same as prepatellar bursitis	Kneeling and crawling	Chronic microtraumatic	Traumatic/hemorrhagic
Subcutaneous calcaneal	Rare	Figure skaters, dancers, rowers	Feet in improperly fitted footwear (e.g., too tight) or high heels	Chronic microtraumatic	Traumatic/hemorrhagic

ACUTE TRAUMATIC/HEMORRHAGIC

Acute traumatic/hemorrhagic superficial bursitis can occur in any superficial bursa, and is typically the result of a direct blow that causes bleeding into the bursa^2,3 (Figure 1). In patients with coagulopathies, and in those receiving anticoagulants, bleeding may occur spontaneously without trauma.¹

CHRONIC

Microtraumatic. Chronic microtrauma is the most common cause of superficial bursitis. Microtrauma results from chronic repetitive friction on the tissue overlying the bursa and its underlying bony prominence ^2–4 (Figure 2).

Olecranon bursitis, also known as miner's elbow, student's elbow, and draftsman's elbow, is the most common superficial bursitis.^2,4–9 Men are more likely to be affected than women, particularly men who perform manual labor (e.g., auto mechanics, carpet layers, plumbers, gardeners) or compete as wrestlers, gymnasts, or dart players.^3,5,6

Olecranon bursitis also occurs in patients on chronic hemodialysis.⁶ Although the pathophysiology is not clearly understood, as many as 7% of those undergoing hemodialysis develop olecranon bursitis in the arm containing the arteriovenous fistula.¹⁰ Repetitive microtrauma to the elbow from leaning on the arm of the chair during dialysis procedures may be the primary cause.

Prepatellar bursitis, also known as housemaid's knee, coal miner's knee, or carpet layer's knee, is the second most common superficial bursitis.^2,3,11 Repetitive compressive and sheer forces between the skin and the patella as a result of frequent kneeling are the main etiologic factors, and the condition is more common among persons with occupations that involve frequent kneeling.^2,3 Although superficial infrapatellar (pretibial) bursitis can also occur, it is a rare condition.^11,12

Subcutaneous calcaneal bursitis, also known as pump bumps, occurs in figure skaters¹³ but is an otherwise uncommon condition mainly caused by wearing improperly fitted footwear or Haglund deformity,¹⁴ a calcified prominence on the posterior and superior aspect of the calcaneus at the Achilles tendon insertion. Haglund deformity is usually caused by chronic microtrauma due to tight shoes, chronic Achilles tendonitis, or chronic childhood apophysitis.^13,14

Inflammatory. Joint crystal disease, most commonly gout (and rarely pseudogout), can cause a chronic inflammatory superficial bursitis. Superficial bursae are not typical locations for an acute gouty attack, but the olecranon and prepatellar bursae are most often affected when it does occur.^4,5 Acute gouty superficial bursitis is usually characterized by acutely swollen, red inflamed bursae, and in rare cases, it can progress to a chronic tophaceous gout with minimal or no pain (Figure 3).

Although rare, inflammatory arthritic disorders such as rheumatoid arthritis can also cause superficial bursitis.^4,5,15

SEPTIC

Septic superficial bursitis is also uncommon. It occurs more often in the olecranon and prepatellar bursae than in other superficial bursae⁹ (Figure 4). It usually arises from infection in nearby tissues, such as cellulitis, because of direct inoculation from trauma, or iatrogenically as a result of an attempt to aspirate an enlarged bursa^9,16 (Figure 5). Limited bursal blood supply means that hematogenous bacterial seeding is rare.⁹

Up to one-half of septic bursitis cases occur in patients with chronic systemic conditions such as diabetes mellitus and chronic kidney disease.^3,5 Patients with alcoholism and those who are immunocompromised are also at risk.

Staphylococcus aureus is responsible for 80% to 85% of septic olecranon and prepatellar bursitis.^17–19 Other organisms that cause septic bursitis are Streptococcus pyogenes (most commonly group A) and, less commonly, Staphylococcus epidermidis.^5,9,17 Rarely, Escherichia coli and Candida species have grown from cultured septic superficial bursal aspirates.¹⁸

Clinical Presentation

Patients with chronic superficial bursitis typically present with swelling over the involved bursa and may report associated occupations or activities, but often have minimal or no pain. Other patients, particularly those with acute traumatic/hemorrhagic bursitis or septic bursitis, can present with significant pain, tenderness, and decreased range of motion. Clinical findings are summarized in eTable A.

		Acute	Chronic			Septic

		Traumatic/hemorrhagic	Microtraumatic	Crystal disease*	Rheumatoid arthritis*	Spontaneous or iatrogenic
Overall prevalence		++	+++	+	+	++
Related clinical findings
Clinical presentation
	Pain	+++	+/−	+++	++	+++
	Nonintact skin	+/−	−	−	+/−	++
	Redness	−	−	++	++	+++
	Decreased motion	+	+	++	++	+++
	History of trauma	+++	+/−	+/−	−	++
	Immune impairment	−	−	−	−	+++
Physical examination findings
	Bursal enlargement	++	+++	+	+	+
	Tenderness	++	+	++	++	+++
	Fever	−	−	−	−	++
	Erythema	−	−	++	++	+++
	Warmth	−	+	+/−	+/−	+++
	Surrounding edema	−	+	+/−	+/−	+++
	Lymphadenopathy	−	−	+/−	−	++
	Fluid drainage	+/−	−	−	−	+
Laboratory test results
	Leukocytosis	−	−	+	+	++
	Increased ESR and CRP levels	−	−	++	++	++
Bursal fluid analysis findings
Color and appearance		Hemorrhagic, serosanguineous	Clear, cloudy, serosanguineous	Cloudy, serosanguineous	Clear, cloudy, serosanguineous	Cloudy, purulent
White blood cells (mm³)		< 10,000	< 1,500	< 20,000	< 60,000	1,000 to 450,000
Gram stain		−	−	−	−	++
Crystals		−	−	+++	−	−
Fluid to serum glucose ratio		≥ 0.5	≥ 0.5	≥ 0.5	≥ 0.5	< 0.5
Positive culture		−	−	−	−	+++
Imaging characteristics
Plain radiography		Enlarged bursa	Enlarged bursa	Enlarged bursa, calcification	Enlarged bursa, calcification	Enlarged bursa
Ultrasonography		Enlarged bursa	Enlarged bursa, thickened bursal sac	Enlarged bursa, thickened bursal sac, calcification	Enlarged bursa, thickened bursal sac, calcification	Enlarged bursa, cellulitis
Color Doppler		Negative	Negative	Hyperemia	Hyperemia	Hyperemia
Magnetic resonance imaging		Enlarged bursa	Enlarged bursa, thickened bursal sac	Enlarged bursa, thickened bursal sac, calcification	Enlarged bursa, thickened bursal sac, calcification	Enlarged bursa, cellulitis
Treatment
Conservative management		Usual	Usual	Occasional	Occasional	No
Aspiration		Occasional	Rarely	Rarely	Rarely	Often
Corticosteroid injection		No	Rarely	Rarely	Rarely	No
Antibiotics		No	No	No	No	Yes
Surgery		No	Rarely	No	No	Rarely
Treat underlying etiology		NA	NA	Yes	Yes	NA

Findings in the history that point to the possibility of septic bursitis include a recent attempt to aspirate the bursa²⁰ (Figure 5A), history of skin trauma near an affected bursa (Figure 5B), and immunocompromising conditions such as diabetes or rheumatologic disorders.^3,5,21–23 A patient with a fever and superficial bursitis should be considered to have septic bursitis until proven otherwise,³ although lack of fever does not rule out the possibility of septic superficial bursitis.²¹ Warmth at the location of the bursa is an effective predictor of infection. One study found that a temperature differential of greater than 2.2°C of the skin overlying the affected bursa and the contralateral unaffected bursa was predictive of septic bursitis, with a sensitivity of 100% and specificity of 94%.²⁴ Skin temperature can be measured using an infrared thermometer.

Diagnosis

The differential diagnosis of superficial bursitis is broad and extends beyond distinguishing infection (septic bursitis) from other causes. Conditions that might be mistaken for bursitis, such as joint effusions, septic and inflammatory arthritis, cellulitis, and Morel-Lavallée lesions (shearing of the skin and subcutaneous tissues from the underlying fascia), must be indentified.^9,25,26 A variety of tests can be helpful in making these distinctions.

IMAGING

Plain radiography is indicated if there is recent trauma with concern for fracture, a foreign body, calcification, or bony abnormality (e.g., Haglund deformity)^1,4,21 (Figure 6).

Ultrasonography can be useful for visualizing an enlarged bursa when there is significant soft tissue edema caused by cellulitis, making it difficult for physical examination to determine whether a bursa is involved^5,27 (Figure 1B).

Color Doppler can be performed as part of diagnostic ultrasonography to help visualize an inflammatory process (hyperemia). A negative color Doppler test result strongly decreases the likelihood of inflammatory bursitis (septic or aseptic). When there is concern for septic bursitis and aspiration of the bursa is unsuccessful, magnetic resonance imaging should be performed (Figure 6). Although the presence of enhancement on imaging cannot differentiate between the inflammatory changes of septic vs. aseptic bursitis, the absence of enhancement indicates that septic bursitis is not present.^5,28,29

BLOOD TESTING

Peripheral blood in patients suspected of having septic bursitis should be sent for blood cell count with differential and C-reactive protein and erythrocyte sedimentation rate testing. Patients with septic bursitis will typically exhibit leukocytosis and have elevations in these test levels. However, these markers may also be elevated in patients with aseptic inflammatory bursitis (eTable A). Additionally, lack of elevated levels and absence of leukocytosis do not rule out the possibility of septic bursitis, particularly at the beginning of an infectious process.²¹

Because the presence of diabetes increases the chance of infection, blood glucose level should be measured to exclude the disease. Blood cultures should also be obtained, particularly in those who are immunocompromised.⁷

ASPIRATION

If uncertainty about the cause of bursitis still remains after conducting a history and physical examination and reviewing applicable blood test and imaging results, particularly if there is a suspicion of septic bursitis, aspiration of the bursal fluid should be performed under sterile conditions with a large-bore (18- to 22-gauge) needle if it has not been done already.^{3,4,8,9,16,17,30–32} Ultrasonography can help with needle placement when aspiration might be difficult (e.g., when assuring needle insertion into a smaller bursa or avoiding adjacent cellulitis).^5,27

Aspiration should be performed using the Z-track method, with the needle inserted into the skin while the overlying skin is pulled horizontally before it is advanced into the bursa.³³ This method prevents leakage of bursal fluid after aspiration and entry of skin bacteria into the bursal sac. Videos demonstrating the technique are available online.

Bursal aspiration should be performed before antibiotics are administered¹⁶; otherwise, antibiotics will diminish the likelihood of isolating the offending organism.

Aspirated fluid should be sent for blood cell count, Gram stain, culture, glucose measurement, and crystal analysis^{3,4,6,9,16,17,21,22,30,34–36} (eTable A). Bursal fluid that is cloudy or purulent in appearance is more likely to represent septic bursitis.

In addition to aiding in diagnosis, bursal aspiration can improve symptoms and reduce bacterial load.^3,5,16 The use of a compressive bandage after aspiration may also help reduce reaccumulation of fluid.^3,16,37 One small study involving joint and soft tissue injections indicated that aspiration in patients on a therapeutic anticoagulation regimen is safe and does not significantly increase the risk of hematoma or bleeding.³⁸

When the bursitis is clearly aseptic and noninflammatory (e.g., absence of acute trauma, pain, tenderness, fever, and warmth), and the patient has full range of motion, bursal aspiration is not recommended because it can potentially lead to iatrogenic septic bursitis.^{1,3–5,8,9,21,35}