Crystallopathies

Gout

Deposition of sodium monourate in the joints.

Risk factors: trauma, starvation, surgery, infection, diuretics.

Clinical features: severe pain, erythema and swelling in affected joint (classically MTP joint). Tophi in avascular areas. X-rays show soft tissue swelling in the early stages, later show juxta-articular punched-out lesions.

Diagnosis: Demonstrate negatively birefringent crystals, neutrophils.

Treatment

Acute attack: high NSAIDs (indomethacin, naproxen, etc.). Peptic ulcers, heart failure, anticoagulants: colchicine 1mg PO, then 0.5mg PO q2h until pain goes, D&V or 10mg given. Renal failure: steroids, expert advice.

Chronic gout: Start xanthine-oxidase inhibitor (allopurinol) 3/52 after attack. If unresponsive, add a uricosuric drug (probenecid). Avoid purine-rich food: offal, oily fish.