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 – 2nd 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 – 1st line, prevents the production of uric acid; C/I - azothioprine S.E - diarrhea, nausea, RASH, itching, drowsiness, can cause LIVER TOXICITYfatal

• 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