Gout - Diagnosis

Highlights	Complications	Medications
Introduction	Risk Factors	Lifestyle Changes
Causes	Diagnosis	Resources
Symptoms	Treatment	References

Diagnosis

Determining which joints are affected is the first step. A physical examination and medical history can reveal a number of significant indictors that help confirm or rule out gout. The following are some examples:

Gout is more likely if arthritis first appears in the big toe than if it first appears elsewhere.
The speed of the onset of pain and swelling is relevant; symptoms that take days or weeks rather than hours to develop probably indicate a disorder other than gout.
Abnormal enlargements in joints that had been affected by previous injury or osteoarthritis are possible signs of gout. This is particularly significant in older women on diuretics.

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Examination of Synovial Fluid

Examination of synovial fluid is the most accurate method for diagnosing gout. It may even be helpful in detecting gout during intercritical periods. The synovial fluid is the lubricating liquid that fills the synovium (the membrane that surrounds a joint and creates a protective sac). The fluid cushions joints and supplies nutrients and oxygen to cartilage, the slippery tissue that coats the ends of bones.

Procedure. The procedure for taking a sample of synovial fluid from an affected joint is called aspiration:

A needle attached to a syringe is inserted into the joint and suction is used to draw the fluid into the syringe.
Local anesthesia is avoided because it can reduce the effectiveness of aspiration, but normally the procedure is only mildly uncomfortable.
Following the procedure there can be some minor discomfort in the area where the needle was inserted, but it usually dissipates quickly.

Synovial fluid analysis is a series of tests performed on synovial (joint) fluid to help diagnose and treat joint-related abnormalities. To obtain a synovial fluid sample, a needle is inserted into the knee between the joint space. When the needle is in place, the synovial fluid is then withdrawn. The sample is sent to the lab for analysis.

Aspiration can cause infection, though this occurs in less than 0.1% of patients. Aspiration sometimes eases a patient?s symptoms by reducing swelling and pressure on the tissue surrounding the joint.

Analyzing the Fluid. After the sample is taken, it is sent to a laboratory, where a specialist examines the sample through a microscope under polarized light. This special light will reveal the presence of monosodium urate (MSU) crystals, which will nearly always confirm a diagnosis of gout. The laboratory can also test the sample for infection.