Gout

Description

• An inflammatory arthritis caused by the accumulation of uric acid crystals in the joints. It often presents as sudden, severe pain, swelling, redness, and warmth in a joint.
• Characterized by deposition of monosodium urate (MSU) crystals in joints and soft tissues, resulting in arthritis, soft tissue masses called tophi, urate nephropathy, and uric acid nephrolithiasis
• The long limb, foot, ankle, and knee are preferentially involved, with the 1st metatarsophalangeal joint (podagra) characteristically affected.
• Flares are usually monoarticular. Polyarticular flares can be associated with pronounced systemic symptoms, including fever, chills, and delirium.
• Gout is related to a hyperuricemia (serum uric acid level >6.8 mg/dL).

Epidemiology

Etiology and Pathophysiology

Four pathophysiological stages:

• Development of hyperuricemia (from uric acid overproduction and/or renal underexcretion)
• Deposition of MSU crystals in joints and soft tissues (changes in uric acid solubility is caused by low temperature, trauma, or acidosis)
• MSU crystals are phagocytosed by synovial macrophages and monocytes resulting in an inflammatory response. The inflammatory response will present clinically as intense pain, swelling, erythema, and warmth.

Risk Factors

• Age >40 years
• Excessive purine consumption from diet (alcohol [especially beer], red meat, seafood, sugar-sweetened beverages)
• Diabetes mellitus, metabolic syndrome, obesity
• Congestive heart failure, chronic kidney disease (CKD), dyslipidemia, hypertension
• Smoking
• Urate-elevating medications: thiazide diuretics, loop diuretics (less of a risk vs. thiazides), niacin, aspirin
• High ambient and humid temperatures
• Transplant-associated gout can happen in immunosuppressed solid organ transplant recipients on low-dose prednisolone and calcineurin inhibitors (cyclosporine and tacrolimus) as these medications increase uric acid (1).
• Hyperuricemia from rapid cell turnover/tumor lysis syndrome (e.g., hemolysis, chemotherapy)

General Prevention

• Diet modification: Avoid purine-rich foods like red meat and shellfish. Reduce alcohol consumption (beer and liquor).
• Maintain fluid intake and avoid dehydration.

Commonly Associated Conditions

• Nontraumatic joint disorders
• Renal disease