Joint effusion

Joint effusion
A traumatic right knee effusion. Note the swelling lateral to the kneecap as marked by the arrow.
Specialty	Orthopedics, rheumatology

A joint effusion is the presence of increased intra-articular fluid. ^[1] It may affect any joint. Commonly it involves the knee (see knee effusion).

Diagnostic approach

The approach to diagnosis depends on the joint involved. While aspiration of the joint is considered the gold standard of treatment, this can be difficult for joints such as the hip. Ultrasound may be used both to verify the existence of an effusion and to guide aspiration. ^[2]

• 
  Skyline view of the patella demonstrating a large joint effusion as marked by the arrow.
• 
  A schematic drawing showing the sail sign which represents an effusion.

Differential diagnosis

Synovial fluid examination ^{[3] [4]}

Type	WBC (per mm3)	% neutrophils	Viscosity	Appearance
Normal	<200	0	High	Transparent
Osteoarthritis	<5000	<25	High	Clear yellow
Trauma	<10,000	<50	Variable	Bloody
Inflammatory	2,000–50,000	50–80	Low	Cloudy yellow
Septic arthritis	>50,000	>75	Low	Cloudy yellow
Gonorrhea	~10,000	60	Low	Cloudy yellow
Tuberculosis	~20,000	70	Low	Cloudy yellow
Inflammatory: Arthritis, gout, rheumatoid arthritis, rheumatic fever

There are many causes of joint effusion. It may result from trauma, inflammation, hematologic conditions, or infections. ^[1]

Septic arthritis

Septic arthritis is the purulent invasion of a joint by an infectious agent ^{[5] [6]} with a resultant large effusion due to inflammation. ^[7] Septic arthritis is a serious condition. It can lead to irreversible joint damage in the event of delayed diagnosis or mismanagement. It is basically a disease of children and adolescence. ^[6]

Gout

Gout is usually present with recurrent attacks of acute inflammatory arthritis (red, tender, hot, swollen joint). It is caused by elevated levels of uric acid in the blood that crystallizes and deposits in joints, tendons, and surrounding tissues. Gout affects 1% of individuals in Western populations at some point in their lives. ^[8]

Trauma

Trauma from ligamentous, osseous or meniscal injuries can result in an effusion. ^[9] These are often hemarthrosis or bloody effusions.^{[ citation needed ]}

Treatment

The treatment for joint effusion includes icing, rest and medication as advised by a doctor. ^[10]

See also

• Swelling (medical)
• Intermittent hydrarthrosis

References

1. Mathison DJ, Teach SJ (November 2009). "Approach to knee effusions". Pediatr Emerg Care. 25 (11): 773–786, quiz 787–788. doi:10.1097/PEC.0b013e3181bec987. PMID   19915432. S2CID   1701019.
2. Marx, John (2010). "Chapter 53". Rosen's emergency medicine: concepts and clinical practice (7th ed.). Philadelphia: Mosby/Elsevier. ISBN   978-0323054720.
3. Flynn JA, Choi MJ, Wooster DL (2013). Oxford American Handbook of Clinical Medicine. US: OUP. p. 400. ISBN   978-0-19-991494-4.
4. Seidman AJ, Limaiem F (2019). "Synovial Fluid Analysis". StatPearls. StatPearls Publishing. PMID   30725799 . Retrieved 2019-12-19.
5. "septic arthritis" at Dorland's Medical Dictionary
6. El-Sobky, T; Mahmoud, S (July 2021). "Acute osteoarticular infections in children are frequently forgotten multidiscipline emergencies: beyond the technical skills". EFORT Open Reviews. 6 (7): 584–592. doi:10.1302/2058-5241.6.200155. PMC   8335954 . PMID   34377550.
7. Marx, John (2010). "Chapter 134". Rosen's emergency medicine: concepts and clinical practice (7th ed.). Philadelphia: Mosby/Elsevier. ISBN   978-0323054720.
8. Chen LX, Schumacher HR (October 2008). "Gout: an evidence-based review". J Clin Rheumatol. 14 (5 Suppl): S55–62. doi:10.1097/RHU.0b013e3181896921. PMID   18830092. S2CID   6644013.
9. Johnson MW (April 2000). "Acute knee effusions: a systematic approach to diagnosis". Am Fam Physician. 61 (8): 2391–2400. PMID   10794580.
10. "A to Z: Joint Effusion". KidsHealth.