Gout

Gout is a metabolic disorder characterized by recurrent episodes of acute inflammatory arthritis caused by deposition of monosodium urate crystals in joints and soft tissues, often associated with hyperuricemia.

Definition

Epidemiology

Prevalence: 1–4% in most developed countries, higher in men
More common in males than females, though incidence increases in postmenopausal women
Typically affects adults aged 40–60 years
Increasing prevalence due to lifestyle factors and aging population
Strong association with obesity, hypertension, chronic kidney disease, and metabolic syndrome

Etiology

Hyperuricemia due to overproduction or underexcretion of uric acid
Dietary factors: high purine intake (red meat, seafood), alcohol (especially beer), sugary drinks
Genetic predisposition affecting urate transporters
Medications: diuretics, low-dose aspirin, cyclosporine
Renal impairment reducing uric acid excretion
Comorbid metabolic disorders (obesity, hypertension, diabetes)

Pathophysiology

Supersaturation of uric acid in blood leading to crystal formation
Deposition of monosodium urate crystals in joints and periarticular tissues
Activation of NLRP3 inflammasome and innate immune response
Inflammatory cytokines (IL-1β, TNF-α) mediate acute arthritis
Chronic deposition leads to tophi formation and joint damage
Crystal-induced inflammation causes pain, swelling, redness, and warmth
Progressive gout can result in joint destruction, nephrolithiasis, and chronic kidney disease