<unk>  is characterized by the inflammation of a bursa and the buildup of the fluid in the bursal sac. A bursa is a small, fluid-filled sac that acts as a cushion between a bone and other moving parts: muscles, tendons, or skin. Over 160 bursa are found throughout the body but relatively few of them can cause<unk> .
Based on the nature of the inflammation,<unk>  may be classified into 2 subtypes: septic and aseptic. The most common<unk>  subtypes include subacromial, olecranon, trochanteric, prepatellar, and retrocalcaneal.
Aseptic<unk>  can be caused by overuse or repetitive injury to the joint, abnormal and bony structure, and/or crystal deposit in the bursa. Additionally, septic<unk>  can be caused by bacterial infection of the bursa through a skin injury following repetitive trauma. Common causes of septic<unk>  include Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus spp.<unk>  must be differentiated from tendonitis, cellulitis, osteoarthritis, ligamentous injuries, and septic arthritis.
The symptoms of<unk>  differ based on the location of the inflammation. Focal swelling, pain, and redness are symptoms common to all forms of<unk> .
The diagnosis of<unk>  is usually made clinically. There are no diagnostic lab findings associated with<unk> . However, patients with septic<unk>  may have elevated ESR, CRP, and  white blood cell count.
Ultrasonography may be a useful tool for confirming the diagnosis of<unk> , while the aspiration of bursal fluids is usually reserved for the diagnosis of septic<unk> .
Medical therapy for non-septic<unk>  depends on the involved bursa and includes the RICE regimen (rest, ice, compression, elevation), NSAIDs, and/or corticosteroid injections. Restriction of activity is encouraged to prevent further injury and promote healing.  Antimicrobials are the mainstay of therapy for septic<unk> . Surgical management is often reserved for non-responders.
Based on the nature of the inflammation,<unk>  may classified into 2 subtypes: septic and aseptic.
Common anatomic locations of<unk>  include the shoulder, elbow, hip, knee, and ankle. The most common<unk>  subtypes include:
Subacromial<unk> 
Olecranon<unk> 
Trochanteric<unk> 
Prepatellar<unk> 
Retrocalcaneal<unk> <unk>  is characterized by acute or chronic inflammation of a bursa and buildup of fluid in the bursa sac. A bursa is a small, fluid-filled sac that acts as a cushion between a bone and other moving parts: muscles, tendons, or skin. Over 160 bursae are found throughout the body, though relatively few of them can cause<unk> .
Aseptic<unk>  can be caused by overuse and repetitive injuries to the joint, abnormal bony structure and crystal deposit in the bursa. It commonly affects the knee or elbow as a result of kneeling or leaning on the elbows longer than usual. Moreover, septic<unk>  can be caused by bacterial infection of the bursa through the skin injury following repetitive trauma.
The following images depict different cases of<unk> :
Prepatellar<unk>  - By Thomas Kees - Own work (Original text: eigenes Archiv (selbst photographiert)), CC BY-SA 3.0 de, https://commons.wikimedia.org/w/index.php?curid=25418133
Prepatellar<unk>  - By Atropos235 - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=4079323
Olecranon<unk>  - By en:User:NJC123 - en:Image:Bursitis_Elbow_WC.JPG, Public Domain, https://commons.wikimedia.org/w/index.php?curid=2814450
Prepatellar<unk>  - By Thomas Kees - Own work (Original text: eigenes Archiv (selbst photographiert)), CC BY-SA 3.0 de, https://commons.wikimedia.org/w/index.php?curid=25418133
Prepatellar<unk>  - By Atropos235 - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=4079323
Olecranon<unk>  - By en:User:NJC123 - en:Image:Bursitis_Elbow_WC.JPG, Public Domain, https://commons.wikimedia.org/w/index.php?curid=2814450
Common causes of<unk>  include:
Aseptic<unk> :
Prolonged pressure, overuse, or strenuous activity
Elbows and knees are most commonly affected because they are rested upon more than many parts of the body with bursae and they also tend to endure the most repetitive use.
Shoulder<unk>  is more commonly due to overuse of the shoulder joint and muscles.
Other inflammatory conditions (e.g., rheumatoid arthritis and spondyloarthritis)
Gout and pseudogout
Elbows and knees are most commonly affected because they are rested upon more than many parts of the body with bursae and they also tend to endure the most repetitive use.
Shoulder<unk>  is more commonly due to overuse of the shoulder joint and muscles.
Septic<unk> :
Staphylococcus aureus
Staphylococcus epidermidis
Streptococcus spp<unk>  symptoms and signs are relatively non-specific. Even after detailed history and physical examination, imaging studies are often necessary to rule out other musculoskeletal conditions.<unk>  must be differentiated from tendonitis, cellulitis, osteoarthritis, ligamentous injuries, and septic arthritis.<unk>  accounts for 400 visits per 100,000 visits to primary care clinic. The exact prevalence and incidence of<unk>  are unknown.
Common risk factors in the development of<unk>  include:
rheumatoid arthritis
osteoarthritis
gout or pseudogout
cellulitis
diabetes mellitus
use of systemic glucocorticoids
alcoholism
malignancy
leukopenia
having a hobby or job that involves repetitive motions (e.g., bicycling, playing baseball, gardening, setting tiles)
Screening for<unk>  is not recommended.<unk>  is often caused by overuse and repetitive injuries to the joint. Symptoms of<unk>  may develop rapidly within 2 to 3 days in an acute form. Patients with<unk>  usually present with edema, erythema, and tenderness over the involved joint. In most cases, after an appropriate lifestyle adjustment,<unk>  will gradually clear within a few days to weeks without any long-term consequences. If left untreated, acute<unk>  may lead to chronic<unk> , which can result in cicatricial adhesions, reduced mobility, and progressive pain.
With proper treatment and an activities adjustment, septic and aseptic<unk>  are associated with an excellent prognosis.
Bursitis
Amyloid arthropathy
Osteoarthritis
Osteochondritis
Shoulder arthritis
Septic arthritis
Synovitis
Synarthrosis