Sodium urate crystals

Gout increased uric acid resulting in sodium urate crystals deposited in the joints... 

Hyperuricemia and chronic or episodic joint pain due to deposition of sodium urate crystals and consequent inflammation (gouty arthritis) are the hallmarks of gout. 

Gout is a metabolic disease in which there is a overproduction of purines. It is characterized by intermittent attacks of acute arthritis produced by the deposition of sodium urate crystals in the synovial tissue of joints. Drugs used for treating gout are allopurinol, probenecid, colchicine, and NSAIDs. 

Figure 25.18. Urate Crystals. Micrograph of sodium urate crystals. Joints and kidneys are damaged by these crystals in gout. [Courtesy of Dr. James McGuire.]...

A second aspect of the precipitation of acute attacks of gout is related to the inflammatory reaction produced by the injection of sodium urate crystals. The historical background for believing that such materials are related to the occurrence of acute attacks is reviewed by McCarty (MIO). Since synovial fluid from patients with acute attacks contains micro-crystalline sodium urate, it appeared reasonable to believe that the presence of these crystals would cause gouty attacks. A number of investigators showed that administration of a microcrystalline sodium urate resulted in attacks in normal human subjects, in dogs, and in gouty patients in a quiescent phase (FI, H12, M4). 

Gout An inflammatory event triggered by the crystallization of sodium urate crystals in the joints as a resnlt of increased levels of sodium urate in the blood. 

Hyperuricemia (gout) is a clinical condition characterized by elevated levels of uric acid that lead to the formation of sodium urate crystals that are found primarily in the joints of the extremities. Which of the following factors contributes most to the formation of urate crystals in the extremities ... 

E. One approach for the treatment of gout is to decrease the levels of uric add production to prevent the development of urate crystals. Allopurinol is an inhibitor of xanthine oxidase enzymatic activity. The administration of allopurinol is an effective treatment of gout because it decreases the amount of uric add produced, which in turn alleviates the formation of sodium urate crystals. 

Acute gout is triggered by the tissue deposition of sodium urate crystals which cause an inllammatory response. In the chronic situation, tophaceous deposits of sodium urate may form in the tissues (Fig. 4). Gout is exacerbated by alcohol. The reason for this is twofold. Ethanol increases the turnover of ATP and urate production. Ethanol in excess may cause the accumulation of organic acids w hich compete with the tubular secretion of uric acitl. Disorders such as ethanol intoxication, diabetic ketoacidosis and starvation lead to elevations of lactic acid. (3-hydroxybutyric acid and acetoacetic acid, and will cause hyperuricaemia. 

Acute gouty arthritis may be diagnosed by examination of synovial fluid from an acutely inflamed joint.. Sodium urate crystals will be observed within polymorphonuclear leukocytes viewed under polarizing light. 

Lotta Topaigne is being treated with allopurinol for gout, which is caused by an accumulation of sodium urate crystals in joints and joint fluid, particularly in the ankle and great toe. Allopurinol is a suicide inhibitor of the enzyme xanthine oxidase, which is involved in the degradation of purine nucleotides AMP and GMP to uric acid (urate). Although hypoxanthine levels increase in the presence of allopurinol, hypoxanthine does not participate in urate crystal formation and precipitation at this concentration. It is excreted in the urine. 

Tophi are accumulations of sodium urate crystals, which are deposited in peripheral areas of the body. The presence of tophi indicates the medication is not effective. 

Causes, Gout is caused by a defect in the body s natural process of breaking down purines (nucleoproteins, which are compounds of one or more proteins and nucleic acid). This results in the production of too much uric acid, which accumulates in the blood, where it combines with sodium to produce sodium urate. Crystals of uric acid are deposited in tissues around the joints. These deposits cause sudden attacks of swelling, most commonly in the feet. 

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