Clinical Background
Gout is caused by crystalline deposition in tissues and joints.
Epidemiology
- Prevalence - 2% in males >30, females >50
- Age - unusual in patients <30 years
- Sex - M>F
Risk Factors
- Elevated uric acid
- Obesity
- Diuretic therapy
- High purine diet
- Alcohol use
- Common triggers in patients with a history of gout - trauma, surgery, psoriasis, flare-ups, diuresis, starting or stopping allopurinol, infections
Pathophysiology
- Uric acid is a byproduct of purine catabolism
- Hyperuricemia is common in gout and is caused by altered purine metabolism
- When solubility limits of uric acid or urate are exceeded, monosodium urate crystals deposit in joints, kidneys and soft tissue
Clinical Presentation
- Usually single joint involvement
- More common in lower extremities
- Most common in first metatarsophalangeal (MTP) joint
- Pain, erythema and swelling of joint
- May cause fever, leukocytosis and/or cellulitis over joint
- Chronic gout
- Tophi depositions in soft tissue
- Joint destruction and erosion
Treatment
- Acute therapy includes NSAIDS, steroids and colchicine
- Chronic therapy includes urate-lowering drugs
Diagnosis
Diagnosis
- Use criteria from the American College of Rheumatology (1977)
| American College of Rheumatology Criteria for Gout |
Gout may be diagnosed if one of the following criteria is present:- Monosodium urate crystals in synovial fluid present during an attack
- Tophi confirmed with crystal examination
- At least six of the following findings:
- Asymmetric swelling within a joint on a radiograph
- First metatarsophalangeal joint is tender or swollen (ie, podagra)
- Hyperuricemia
- Maximal inflammation developed within one day
- Monoarthritis attack
- More than one acute arthritis attack
- Redness observed over joints
- Subcortical cysts without erosions on a radiograph
- Suspected tophi
- Synovial fluid culture negative for organisms during an acute attack
- Unilateral first metatarsophalangeal joint attack
- Unilateral tarsal joint attack
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|
- Laboratory testing
- Synovial fluid examination for cells and crystals; gold standard for diagnosis is presence of uric acid crystals in fluid
- Serum uric acid; may be elevated; however, lack of elevation does not rule out gout
- Complete blood count (CBC); modest leukocytosis may be present; may be helpful in discriminating septic joint from gout
- Blood urea nitrogen (BUN) and creatinine to evaluate renal function
Differential Diagnosis
- Other crystalline arthritis; eg, pseudogout
- Reactive arthritis
- Cellulitis
- Septic arthritis
Tests generally appear in the order most useful for common clinical situations
| Test name: Crystals
|
| ARUP #: 0009500 |
| Methodology: Manual/Polarized Microscopy
|
| Use: Gold standard for diagnosis of gout |
| Limitations: Lack of crystals does not rule out gout |
| Test name: Uric Acid, Serum or Plasma
|
| ARUP #: 0020026 |
| Methodology: Spectrophotometry
|
| Use: Aid in diagnosis of gout |
| Limitations: Lack of elevation does not rule out gout |
| Test name: CBC with Platelet Count
|
| ARUP #: 0040002 |
| Methodology: Automated Cell Count
|
| Use: Differentiate gout from septic joint |
| Test name: Urea Nitrogen, Serum or Plasma
|
| ARUP #: 0020023 |
| Methodology: Spectrophotometry
|
| Use: Assess renal function in gout |
| Test name: Creatinine, Serum or Plasma
|
| ARUP #: 0020025 |
| Methodology: Spectrophotometry
|
| Use: Assess renal function in gout |
Additional Tests Available
| Test name: Uric Acid, Urine
|
| ARUP #: 0020481 |
| Methodology: Spectrophotometry
|
| Comments: |
References
Guidelines
Zhang W, Doherty M, Pascual E, Bardin T, Barskova V, Conaghan P, Gerster J, Jacobs J, Leeb B, Liote F, McCarthy G, Netter P, Nuki G, Perez-Ruiz F, Pignone A, Pimentao J, Punzi L, Roddy E, Uhlig T, Zimmermann-Gorska I. EULAR evidence based recommendations for gout. Part I: Diagnosis. Report of a task force of the Standing Committee for International Clinical Studies Including Therapeutics (ESCISIT). Ann Rheum Dis.
2006;
65(
10):
1301-1311.
Cited References
Eggebeen AT. Gout: an update. Am Fam Physician.
2007;
76(
6):
801-808.
General References
Akahoshi T, Murakami Y, Kitasato H. Recent advances in crystal-induced acute inflammation. Curr Opin Rheumatol.
2007;
19(
2):
146-150.
Becker MA, Jolly M. Hyperuricemia and associated diseases. Rheum Dis Clin North Am.
2006;
32(
2):
275-2vi.
Chen LX, Schumacher HR. Gout: can we create an evidence-based systematic approach to diagnosis and management?. Best Pract Res Clin Rheumatol.
2006;
20(
4):
673-684.
Corrado A, D'Onofrio F, Santoro N, Melillo N, Cantatore FP. Pathogenesis, clinical findings and management of acute and chronic gout. Minerva Med.
2006;
97(
6):
495-509.
Keith MP, Gilliland WR. Updates in the management of gout. Am J Med.
2007;
120(
3):
221-224.
Lillicrap M. Crystal arthritis: contemporary approaches to diseases of antiquity. Clin Med.
2007;
7(
1):
60-64.
Underwood M. Diagnosis and management of gout. BMJ.
2006;
332(
7553):
1315-1319.
Underwood M. Gout. Clin Evid.
2006;
(
15):
1561-1569.
Medical Reviewers
Lehman, Christopher M., M.D. Co-Medical Director, University Hospital Clinical Laboratory; Associate Professor, Clinical Pathology, University of Utah
Roberts, William L. , M.D., Ph.D. Medical Director, Automated Core Laboratory at ARUP Laboratories; Professor, Pathology, University of Utah
Comprehensive Review: May 2008
Last Update: July 2008
