Pathophysiology Gout can be considered a disorder of metabolism that allows uric acid/urate to accumulate in blood and tissues. When tissues becor aturated,., forming crystals. In addition, thE CryS are less soluble under acid conditions y reactive urate crystals are normally coated with serum protei ns(apolipoprotein apo]E or apo B)that physically inhibit th e binding of the crystals to cell receptors. A gout attack may be triggered by either a release of uncoated crystals(eg, due t o partial dissolution of a microtophus caused by changing ser um urate levels) or precipitation of crystals in a supersaturate d microenvironment (eg, release of urate due to cellular dam age) 浙医二院
7 浙医二院 Pathophysiology Gout can be considered a disorder of metabolism that allows uric acid/urate to accumulate in blood and tissues. When tissues become super saturated, …, forming crystals. In addition, the crystals also are less soluble under acid conditions. reactive urate crystals are normally coated with serum protei ns (apolipoprotein [apo] E or apo B) that physically inhibit th e binding of the crystals to cell receptors. A gout attack may be triggered by either a release of uncoated crystals (eg, due t o partial dissolution of a microtophus caused by changing ser um urate levels) or precipitation of crystals in a supersaturate d microenvironment (eg, release of urate due to cellular dam age)
Clinical---History Podagra is the initial joint manifestation in ca-o gout ca ses. Eventually, it is involved in of cases Other than the great toe, the most common sites of gouty arthritis are the ankle, wrist, and knee. In early gout, only 1 or 2 joints are usually involved Gout attacks begin abruptly and reach maximum intensit y within 8-12 hours. The joints are and exquisite y tender; even a bed sheet on the swollen joint is uncomf ortable. Untreated, the first attacks resolve spontaneously in less than 2 weeks. Gout initially presents as polyarticul ar arthritis in 10% of patients 浙医二院
8 浙医二院 Clinical---History Podagra is the initial joint manifestation in 50% of gout ca ses. Eventually, it is involved in 90% of cases. Other than the great toe, the most common sites of gouty arthritis are the ankle, wrist, and knee. In early gout, only 1 or 2 joints are usually involved. Gout attacks begin abruptly and reach maximum intensit y within 8-12 hours. The joints are red, hot, and exquisitel y tender; even a bed sheet on the swollen joint is uncomf ortable. Untreated, the first attacks resolve spontaneously in less than 2 weeks. Gout initially presents as polyarticul ar arthritis in 10% of patients
Clinical---History The pattern of symptoms in untreated gout changes over time. The attacks become more polyarticular. Although m ore joints may become involved, inflammation in a given j oint may become less intense. More proximal and upper. extremity joints become involved. Attacks occur more freq uently and last longer Eventually, patients may develop chronic polyarticular art hritis. Patients with gout are profoundly more likely to dev elop renal stones 浙医二院
9 浙医二院 Clinical---History The pattern of symptoms in untreated gout changes over time. The attacks become more polyarticular. Although m ore joints may become involved, inflammation in a given j oint may become less intense. More proximal and upperextremity joints become involved. Attacks occur more freq uently and last longer. Eventually, patients may develop chronic polyarticular art hritis. Patients with gout are profoundly more likely to dev elop renal stones
Clinical-Physical Examination The classic location of tophi is along the helix of the ear., includin g the fingers, toes, prepatellar bursa, and along the olecranon. Rar ely, a creamy discharge may be present All manitestations of gout in the eye are secondary to deposition of urate crystals within the ocular tissue Gout. Chronic tophaceous gout Gout. Tophaceous deposits on elbow in an untreatedpatientwithend Gout Tophaceous deposits in ear stage renal disease 10
10 浙医二院 Clinical--Physical Examination The classic location of tophi is along the helix of the ear …, includin g the fingers, toes, prepatellar bursa, and along the olecranon. Rar ely, a creamy discharge may be present . All manifestations of gout in the eye are secondary to deposition of urate crystals within the ocular tissue •Gout. Tophaceous deposits on elbow •Gout. Tophaceous deposits in ear •Gout. Chronic tophaceous gout in an untreated patient with endstage renal disease
Workup -Approach Considerations 少 Arthrocentesis关节穿刺术 of the affected joint is mandatory for all pati ents with new onset of acute monoarthritis. Tophi also may be aspi rated for crystal analysis under polarizing microscopy Septic arthritis must be diagnosed and treated promptly, because ir reversible damage can occur wIthin and the joint can be completely destroyed within 24-48 hours Send joint fluid for fluid analysis, including cell count and differentia I, Gram stain, culture and sensitivity, and microscopic analysis for c rystals In gout, crystals of monosodium urate (MSU) appear as ped intracellular and extracellular crystals. pseudogout shows cal cium pyrophosphate,焦磷酸盐(CPP) crystals, which appear shorter th an MSU crystals and are often 长斜方形的 浙医二院
11 浙医二院 Workup –Approach Considerations Arthrocentesis关节穿刺术 of the affected joint is mandatory for all pati ents with new onset of acute monoarthritis . Tophi also may be aspi rated for crystal analysis under polarizing microscopy Septic arthritis must be diagnosed and treated promptly, because ir reversible damage can occur within 4-6 hours, and the joint can be completely destroyed within 24-48 hours. Send joint fluid for fluid analysis, including cell count and differentia l, Gram stain, culture and sensitivity, and microscopic analysis for c rystals. In gout, crystals of monosodium urate (MSU) appear as needle-sha ped intracellular and extracellular crystals. ..pseudogout shows cal cium pyrophosphate焦磷酸盐 (CPP) crystals, which appear shorter th an MSU crystals and are often rhomboidal.长斜方形的