<prompt> True about gout is -Most common joint involved is first meta transophaiangeal of big toeChondro-calcinosisPyrophosphate crystalsPositive birefringent  <response>: A most common joint involved in first metatarsaphalangeal of big toe 1097 - Davidson 21st 77-80 Apley 9th.GOUTTrue crystal deposition disease, presence of monosodium urate monohydrate MSU crystals, especially the firstMTP joint and small joints of feet and hands. Bursitis - commonly of the olecranon bursaCrystal associated arthritis and deposition in connective tissueCrystalAssociation Monosodium urate monohydrate Acute gout Chronic tophaceous gout Calcium pyrophosphate dehydrateAcute pseudo goutChronic pyrophosphate arthropathyChondrocalcinosis Basic calcium phosphatesCalcific periarthritis calcinosis Cholesterol Chronic effusion in RA Calcium oxalate Acute arthritis in dialysis patientsConfirmation of diagnosis - negatively birefringent urate crystals in the synovial fluids Hyperuricaemia is not diagnostic and is often seen in normal middle aged men X-ray acute attack shows only soft tissue swelling chronic: - Joint space narrowing, secondary osteoarthritis. Tophi appears as characteristics punched out cyst or deep erosions in para-articular bone ends. Bone destruction is more marked may resemble neoplastic disease.GOUTPSEUDOGOUT Smaller joint Large joint Pain intense Pain moderate Joint inflamed Joint swollen Hyperuricaemia Chondrocalcenosis Uric acid crystals Calcium pyrophosphate crystals Meniscus calcification may be seen on X-ray knee joint. 