Bursitis

Bursitis

KEY FACTS

Terminology

• Bursitis: Inflammation of lining of bursa

Imaging

• Majority of bursae are not visible on US unless distended with fluid or proliferative synovial tissue
• Acute bursitis: Thin-walled bursa distended with hypoechoic fluid, peribursal hyperemia
• Chronic bursitis: Thickening of bursal wall, more mature synovial proliferation, more echogenic content, & increased likelihood of intrabursal hyperemia
- Can simulate soft tissue mass or abscess
- If echogenic foci in distended bursa, consider crystal deposition
• Most bursae are accessible to US examination
- Use minimal transducer pressure to avoid effacement of superficial bursae
- Amiable to US-guided aspiration ± injection

Top Differential Diagnoses

• Cystic collection from underlying structure, e.g., parameniscal cyst
• Abscess or collection
• Cyst adjacent to bursa, e.g., epidermoid or hematoma

Clinical Issues

• Treatment
- Rest; antiinflammatory agents: US-guided corticosteroids ± long-acting, local anesthetic injection
- Excision for resistant cases

Diagnostic Checklist

• Small amount of fluid is normal in subacromial-subdeltoid bursa, deep infrapatellar bursa, & retrocalcaneal bursa
• Bursitis is common; infective bursitis is uncommon
• Synovial-type bursa are prone to every synovial-based pathology

Clinical photo shows a patient with posterior elbow swelling that has been present for years but recently increased in pain and size.

Clinical photo shows a patient with posterior elbow swelling that has been present for years but recently increased in pain and size.

Transverse US shows a large olecranon bursitis with a moderately thickened bursal wall . The bursa is distended by fluid and synovial proliferation and overlies the olecranon process . Olecranon bursae frequently have a thickened wall, internal debris, and septa. A noninflamed olecranon bursa is not visible on US.

Transverse US shows a large olecranon bursitis with a moderately thickened bursal wall . The bursa is distended by fluid and synovial proliferation and overlies the olecranon process . Olecranon bursae frequently have a thickened wall, internal debris, and septa. A noninflamed olecranon bursa is not visible on US.

Longitudinal US of the same bursa shows the distended, inflamed olecranon bursa with several thick internal septations , giving the bursa a multiloculated appearance. The normal triceps tendon insertion into the olecranon process is shown.

Longitudinal US of the same bursa shows the distended, inflamed olecranon bursa with several thick internal septations , giving the bursa a multiloculated appearance. The normal triceps tendon insertion into the olecranon process is shown.

Longitudinal color Doppler US shows moderate hyperemia of the thickened bursal wall and peribursal tissues. The internal content and septations show no hyperemia.

Longitudinal color Doppler US shows moderate hyperemia of the thickened bursal wall and peribursal tissues. The internal content and septations show no hyperemia.

TERMINOLOGY

Synonyms

• Bursopathy, student’s elbow (olecranon bursitis), ischial tuberosity (ischiogluteal) bursitis, trochanteric (hip) bursitis, prepatellar bursitis (housemaid’s knee), infrapatellar bursitis (preacher’s knee)

Definitions

• Bursitis: Inflammation of lining of bursa
- Bursa: Synovial-lined sac interspersed between tissues at areas of friction
- 2 types of bursae
  - – Synovial bursae: Constant synovial-lined bursae, which develop in utero in defined anatomical locations
  - – Adventitious bursae: Nonsynovial-lined bursae, which are acquired post partum due to friction between opposing tissues

IMAGING

General Features

• Best diagnostic clue
- Fluid-distended sac in typical location
• Location
• Size
- Few mm to several cm, depending on degree of bursal distension
• Morphology
- Communicating or noncommunicating bursa
  - – Communicating refers to bursa communicating with adjacent joint, e.g., iliopsoas bursa

Radiographic Findings

• Radiography
- Soft tissue swelling

Ultrasonographic Findings

• General
• Subacromial-subdeltoid bursitis
• Olecranon bursitis
- Common site for crystal deposition (echogenic foci within distended bursa)
• Ischial tuberosity bursitis: Large, irregular bursa with moderate wall thickening ± internal septa ± debris
• Iliopsoas bursitis: Large bursa beneath musculotendinous portion of iliopsoas muscle, anterior to hip joint capsule
- Usually associated with hip arthropathy, e.g., inflammatory arthropathy or osteoarthritis
• Trochanteric bursitis: Uncommon
- Most cases of trochanteric pain syndrome due to gluteus medius, minimus tendinosis, or tears
• Semimembranous bursitis: May become inflamed due to impingement against osteophytes over medial aspect of tibial plateau
• Pes anserinus bursitis: Large, distended bursa indented by 3 tendons (looks like goose foot)
- Prone to synovial proliferation
• Prepatellar bursitis: Often just subtle, hypoechoic, ill-defined band in prepatellar tissues
- Usually due to repetitive trauma from kneeling (e.g., housemaid, carpet layer)
- Occasionally infected (penetrating trauma)
• Infrapatellar bursitis: Similar to prepatellar bursitis but located more distally
• Retrocalcaneal bursitis: Small amount of fluid in retrocalcaneal bursa is seen in 35% of normal subjects
- Larger amount of fluid, bursal wall thickening, synovial proliferation, & peribursal or intrabursal hyperemia are indicative of bursitis
- Nearly always associated with Achilles tendinosis

MR Findings

• T1WI
- Homogeneous decreased signal intensity mass at typical location
• T2WI
• T1WI C+
- ± immediate bursal wall enhancement with delayed enhancement of bursal content

Imaging Recommendations

Tags: Diagnostic Ultrasound Musculoskeletal

Apr 9, 2020 | Posted by admin in MUSCULOSKELETAL IMAGING | Comments Off

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