Joint effusion

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

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

Diagnostic approachEdit

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]

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  Skyline view of the patella demonstrating a large joint effusion as marked by the arrow.

 
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  A schematic drawing showing the sail sign which represents an effusion.

Differential diagnosisEdit

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 = gout, rheumatoid arthritis, rheumatic fever

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

Septic arthritisEdit

Septic arthritis is the purulent invasion of a joint by an infectious agent^[5] with a resultant large effusion due to inflammation.^[6]

GoutEdit

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.^[7]

TraumaEdit

Trauma from ligamentous, osseous or meniscal injuries can result in an effusion.^[8] These are often hemarthrosis or bloody effusions.

TreatmentEdit

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The treatment for Joint effusion include icing, rest and medication as advised by your Doctor. 

This article uses material from the Wikipedia article  Metasyntactic variable, which is released under the  Creative Commons Attribution-ShareAlike 3.0 Unported License.