Bursitis
Bursitis is inflammation of a bursa, a synovial-lined sac that reduces friction between the skin, soft tissues and bone. This article focuses on the classic superficial bursitides: olecranon bursitis at the posterior elbow and prepatellar bursitis at the anterior knee.
Classification, Causes and Risk Factors
Bursitis refers to the inflammation of a bursa – a synovial-lined sac located between the skin and bone to reduce friction during movement
- Olecranon bursitis: inflammation of the olecranon bursa, located between the skin and the olecranon process at the posterior elbow
- Prepatellar bursitis: inflammation of the prepatellar bursa, located between the skin and the patella at the anterior knee
Bursitis can be classified as:
| Aseptic bursitis | Most common form of bursitis, characterised by sterile inflammation / fluid accumulation within the bursa
May occur after:
|
| Septic bursitis | Characterised by infection of the bursa, usually by bacteria
Infection may occur following:
|
Clinical Features
Olecranon Bursitis
Olecranon bursitis is also known as “student’s elbow”, “miner’s elbow”, “draftsman’s elbow”.
It is associated with repeated pressure or leaning on the elbow, such as in:
- Students or office workers who frequently lean on a desk
- Miners
- Plumbers
- Mechanics
- Gardeners
Typical presentation:
- Swelling over the olecranon process that appears over hours to days
- Fluctuant swelling on palpation
- ROM is usually preserved and painless (except at full flexion when the swollen bursa is compressed)
Features that may indicate septic bursitis:
- Painful, red, hot swollen bursa (esp. if progressively worsening)
- Marked tenderness over the bursa
- Presence of abrasion, laceration or puncture wound over the bursa
- Local cellulitis
- Fever
- Systemic features (e.g. tachycardia, hypotension, change in mental status)
Significant pain with passive elbow movement or a markedly reduced ROM should raise concern for septic arthritis or another intra-articular pathology, rather than simple bursitis.
Prepatellar Bursitis
Prepatellar bursitis is also known as “housemaid’s knee”, “carpet layer’s knee”, “coal miner’s knee”.
It is associated with repeated kneeling or crawling, such as in:
- Cleaners / housemaids who frequently kneel during cleaning
- Carpet layers
- Plumbers
- Roofers
- Concrete workers
- Miners
Typical presentation:
- Swelling over the anterior knee (directly over the patella) that develops over hours to days
- Fluctuant swelling on palpation
- ROM is usually preserved and painless (except at full flexion when the swollen bursa is compressed)
Features that may indicate septic bursitis:
- Painful, red, hot swollen bursa (esp. if progressively worsening)
- Marked tenderness over the bursa
- Presence of abrasion, laceration or puncture wound over the bursa
- Local cellulitis
- Fever
- Systemic features (e.g. tachycardia, hypotension, change in mental status)
Significant pain with passive knee movement or a markedly reduced ROM should raise concern for septic arthritis or another intra-articular pathology, rather than simple bursitis.
Investigation and Diagnosis
Bursitis is usually a clinical diagnosis. Investigations are not routinely required in clear, uncomplicated cases.
Consider the following investigations if indicated:
| Investigation | Indication / purpose / description |
|---|---|
| Bursal aspiration | Bursal aspiration should be performed if septic bursitis is suspected or if there is any doubt
Fluid should be sent for:
Clinical features alone cannot reliably differentiate septic from non-septic bursitis. Bursal aspiration with analysis of bursal fluid is required to confirm or exclude infection. |
| X-ray | Indicated if a bony pathology is suspected, such as:
|
| Blood tests |
|
Typical investigation findings in septic bursitis:
- Blood tests
- ↑ CRP and ESR
- ↑ WCC (or can be normal)
- Blood cultures may be +ve if there is sepsis
- Bursal aspiration
- Appearance: purulent or cloudy
- Cell count: ↑ WCC with neutrophil / polymorph predominance
- Gram stain may show organisms (can be -ve)
- Culture may grow bacteria (most common: Staphylococcus aureus)
- ↓ Glucose level compared to serum level
Management
Hospital admission criteria:
- Suspected septic joint (joint with limited ROM)
- Signs of severe infection or systemic toxicity
- Extensive cellulitis
- If expertise is not available in primary care (e.g. if bursal aspiration is necessary, or I&D of an abscess is necessary)
- Consider in those who are immunocompromised or have comorbid medical conditions (e.g. diabetes, RA)
Aseptic Bursitis
Initial management:
| Conservative self-care measures |
|
| Therapeutic aspiration | Consider to improve symptoms and joint function
Esp. if the effusion is large |
If there is no response to conservative measures and/or aspiration → consider corticosteroid injection
- Important: septic bursitis must be excluded before any injections as it may risk introducing organisms or aggravating infection
Consider referral if an aseptic bursitis does not respond after 2 months of conservative measures (refer sooner if their symptoms are pronounced, for example significant discomfort).
Septic Bursitis
Treat with oral antibiotics (where possible, start antibiotics AFTER bursal aspiration has been performed)
Choice of empirical antibiotics (before culture results are available):
- 1st line: flucloxacillin (to cover staphylococcal and streptococcal species)
- 2nd line (e.g. penicillin allergic): clarithromycin or erythromycin (for those who are pregnant or breastfeeding)
Admit or refer (depending on severity of symptoms) if there is inadequate response after 3-5 days of antibiotic treatment.
Also offer standard conservative self-care measures (same as those for aseptic bursitis):
- Rest the joint
- Avoid activities that can cause trauma or put direct pressure on the joint
- Use protective elbow or knee pads
- Apply ice to reduce swelling
- Simple analgesia (e.g. paracetamol or NSAIDs)
- Topical NSAIDs may be tried initially before using oral NSAIDs