Gout النقرس (داء الملوك)
INSTRUCTION Examine this patient's hands or examine the feet. SALIENT FEATURES History · Usually acute pain at the base of great toe, worse at night and associated with redness. · Occasionally multiple joints involved. · Systemic symptoms, e.g. low-grade fever. Examination Chronic tophaceous deposit with asymmetrical joint involvement. Proceed as follows: · Tell the examiner that you would like to proceed as follows: · Examine the helices of the ears, olecranon bursae and Achilles tendons for tophi. · Examine the feet or hands. Note. Uric acid crystals are negatively birefringent, needle shaped and may be deposited in bursae and bone marrow. They are demonstrable in synovial fluid within leukocytes and free in the fluid during attacks of gouty arthritis. They react with nitric acid and ammonium hydroxide to give a purple colour (murexid test). DIAGNOSIS This patient has a painful great toe with swelling of the joint (lesion) due to gout (aetiology) and is unable to walk because of the pain (functional status). QUESTIONS What is the basic pathophysiology of gout? Gout is a metabolic disorder of purine metabolism. It is characterized by hyper-uricaemia due to either overproduction (75%) or underexcretion (25%) of uric acid. What are the different clinical manifestations of gout? · Asymptomatic hyperuricaemia. · Acute arthritis. · Chronic arthritis. · Chronic tophaceous gout. How would you treat an acute attack of gout? Prescribe an NSAID such as indometacin (indomethacin). Refractory gout may require steroids. What factors may precipitate acute gouty arthritis? Drugs (diuretics, aspirin), copious consumption of alcohol, dehydration, surgery, fasting, food high in purines (sweetbreads, liver, kidney and sardines). ADVANCED-LEVEL QUESTIONS Under what circumstances would you treat hyperuricaemia ? Frequent attacks of acute arthritis, renal damage and consistently raised serum uric acid levels. Before attempting to lower serum uric acid levels it is prudent to use colchicine to prevent acute attacks. What is the drug of choice for controlling hyperuricaemia? Allopurinol (a xanthine oxidase inhibitor). What drugs would you use if the patient was allergic to allopurinol? Uricosuric drugs such as probenecid, sulfinpyrazone. What is pseudogout? Pseudogout is an acute arthritis resulting from the release of calcium pyrophosphate dihydrate crystals (deposited in the bone and cartilage) into the synovial fluid. Gout was recognized as early as the 4th century BC. Two concepts have prevailed: that it occurs mainly in sexually active mature men and that gastronomic and sexual excesses may precipitate acute attacks. Antonj van Leewenhoeck (1632-1723) described the microscopic appearance of urate crystals from gouty tophus. In 1847, Alfred Garrod, in London, identified uric acid in the serum of a gouty man. James Wyngaarden, contemporary Professor of Medicine, Duke University, USA, whose chief interest is metabolic and genetic diseases.Gout