Gout By Shravya & Helen

Gout is… An inflammatory arthritis associated with hyperuricaemia and intra-articular sodium urate crystals

Gout is prevalent… Mainly in deveoped countries In Europe and USA it is approx 0.2% –Presence of hyperuricaemia is 5% In men more than women (10:1) Rarely presents before young adult or premenopausal females Prevalence in older females is increasing with increased diuretic groups Hyperuricaemia common in certain ethnic groups- Maoris

Gout presents... Typically in middle-aged male with sudden, agonising pain, swelling and redness of first MTP (60%) Can also be seen in ankle, foot, small joints of hand, wrist, elbow or knee Untreated, lasts ~7 days Recovery associated with desquamation of overlying skin In severe attacks, overlying cellulitis males gout difficult to distinguish clinically from infective cellulitis Chronic polyarticular seen mainly in elderly with long- standing diuretic use May see tophi (smooth white sodium urate deposits) in skin and around joints. –Also on pinna, fingers & Achilles tendon

Differentials include… Septic arthritis Haemarthrosis Pseudogout Palindromic RA Cellulitis

Causes of Gout… Hereditary Dietary purine increase Alcohol excess Diuretics Leukaemia Cytotoxics (tumour lysis) Renal impairment Gout is also a marker for conditions such as: –Hypertension –IHD –Metabolic syndrome

Pathogenesis Hyperuricaemia is a major determinant for developing gout Blood Uric acid levels depend on –balance b/w purine synthesis and ingestion og dietary purines –Elimination of urate by kidney & intestine Uric acid is produced in the last step in breakdown of purines –Uric acid is completely filtered by the glomerulus –It is then mostly reabsorbed in the proximal tubule and 50% secreted by the distal tubule –Low-dose aspirin blocks urate secretion –High-dose aspirin also blocks reabsorption  increased net excretion –Insulin resistance enhanses urate resorption 90% of pts with gout have impaired excraition of urate

Investigations Synovial Fluid Analysis – typical negatively birefringent needle- shaped MSU crystals → Can be extra or intracellular → Not sensitive Leucocytosis/ESR/CRP - raised during acute attack

Serum Uric Acid levels - ↑  Not specific in acute attack Radiography – Hallmarks of gout are normal mineralization, joint space preservation, sharply marginated erosions with sclerotic borders, overhanging edges, and asymmetric polyarticular distribution  Tophi seen in late gout

Treatment NSAIDS – naproxen or indomethacin  C/I: corticosteroids (prednisolone) Colchicine – 2 nd Line; used prophylactically;  C/I - GFR<10 mL/min; hepatic dysfunction, biliary obstruction, or inability to tolerate diarrhea  S.E doserelated - nausea, vomiting, abdominal pain, diarrhea, anaemia, neutropenia Allopurinol – 1 st line, prevents the production of uric acid; C/I - azothioprine  S.E - diarrhea, nausea, RASH, itching, drowsiness, can cause LIVER TOXICITY fatal Probenecid

Surgery – late or untreated gout  orthopaedic attention Avoid alcohol Arthrosclerosis and Gout associated  advice low-cholesterol diet Untreated gout can lead to severe joint destruction and renal impairment