Gout

Study Notes

Gout is a type of microcrystal synovitis caused by monosodium urate crystal deposition in joints.
It results from abnormal uric acid metabolism.
This chronic disease can lead to tophi (skin deposits) and potential urate stone formation in the urinary tract.

Gout is the most common inflammatory arthritis in men and post-menopausal women.
It's rare in pre-menopausal women due to enhanced uric acid excretion by estrogen.
Incidence is increasing with rising obesity and metabolic syndrome.

Decreased Uric Acid Excretion (90% cases): Conditions like renal failure, lactic acidosis, lead poisoning, alcohol consumption, and certain medications (e.g., thiazides, loop diuretics, aspirin) can decrease uric acid excretion.
Increased Uric Acid Production: Conditions like myeloproliferative disorders, psoriasis, and high-purine diets can increase uric acid production.
Dietary Intake: Foods high in purines (red meat, shellfish, high fructose) contribute to increased uric acid levels.
Metabolic Syndrome: Obesity, diabetes, hypertension, dyslipidemia contribute to the development and progression of gout.

Uric acid levels depend on dietary purines and endogenous metabolism.
Xanthine oxidase plays a key role in converting hypoxanthine to xanthine to uric acid.
Imbalance in the synthesis and excretion of uric acid leads to crystal deposition in joints.

Acute Gout: Characterized by severe pain, tenderness, swelling, redness, and warmth in joints, predominantly the first metatarsophalangeal joint (podagra). Typically self-limiting within 5-14 days, worsening in early morning.
Chronic Gout: Symptoms include joint deformities, asymmetrical arthritis, functional impairment, and tophi (nodules on extensor surfaces). Renal complications (kidney stones and interstitial nephritis) can also occur.

Serum Uric Acid: May be normal during an acute attack.
Joint Fluid Analysis: Diagnostic for needle-shaped monosodium urate crystals.
Imaging: Normal X-rays during acute attacks; chronic gout can show erosions and punched-out lesions.
Other Tests: Complete blood count (CBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), renal function, and lipid profile are used for comprehensive evaluation.

Acute Gout: First-line treatment is colchicine (0.5mg 2-4 times a day). Non-steroidal anti-inflammatory drugs (NSAIDs) and corticosteroids are also used, as well as ice packs, and joint aspiration when appropriate. Biologic agents (e.g., anakinra) are reserved for resistant cases.
Chronic Gout: Treatment focuses on lifestyle modifications—reducing alcohol intake, weight loss, and limiting purine-rich foods. Urate-lowering therapy is also a cornerstone of management.