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24 Cards in this Set
- Front
- Back
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What is gout?
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- Severe pain and inflammation usually of one joint
- Usually affect 1st MTP (big toe) joint, ankles, or knees - Typically middle aged males |
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What is the characteristic finding in the synovial fluid of gout?
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Monosodium Urate (MSU) Crystals
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What is the main characteristic of gout?
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Hyperuricemia and MSU crystal deposition
Note: Hyperuricemia alone is NOT adequate for dx |
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Who normally is affected by gout?
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Middle aged men
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Uric acid the end product of what metabolism?
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End product of purine metabolism
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What are the 3 sources of urate?
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1. Ingestion of foods containing purines
2. Endogenous synthesis or purine nucleotides 3. Breakdown of tissue nucleic acid |
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What is the function of PRPP synthetase?
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Part of salvage pathway
Increases PRPP which then INCREASES purine synthesis - Ultimate consequence of PRPP sythetase superactivity is HYPERURICEMIA |
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What is the function of amidophosphoribosyltransferase?
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- Catalyzes the rate limiting step of de-novo purine synthesis
- Increased activity leads to hyperuricemia |
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What is the function of HGPRT?
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Catalyzes the single step salvage pathway
- DEFICIENCY leads to hyperuricemia |
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What is the function of Xanthine Oxidase (XO)?
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Catalyzes final 2 steps toward uric acid production
- once produced, the process toward urate production is irreversible |
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How is urate eliminated/excreted?
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1/3 excreted through GI tract
2/3 excreted by kidneys (in urine) |
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What transporter in the PCT is responsible for reabsporption of filtered urate?
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URAT1 (urate anion exchanger)
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Stimulaton of URAT1 leads to what?
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Leads to increased urate reabsorption and hyperuricemia
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What is hyperuriciema?
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High urate in BLOOD (not in urine)
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What are the 2 causes of hyperuricemia?
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1. Urate overproduction (10%)
2. Urate underexcretion (90%) |
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What are the 2 main causes of primary hyperuriciemia?
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1. HGPRT Deficiency
2. PRPP sythetase superactivity |
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Excessive dietary intake of what can lead to seconday hyperuricemia?
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Organ meats, sardines, anchovies, shellfish
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How does alcohol cause gout?
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Accerlerates ATP breakdown (overproduction)
Increases lactic acid accumulation which stimulates URAT1 (underexcretion) |
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What are tophi?
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Deposits of MSU crystals
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What organ is often affected by hyperuricemia?
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The kidney - occurs with precipitation of uric acid crystals in collecting ducts and ureters
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What recently disscovered intracellular pattern recognition receptor appears to have a key role in pathoenesis of acute gout?
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Inflammasomes
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What is the most important cytokine in gout?
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IL-1B --> results in activation of NH-kB
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How acute gout treated?
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NSAIDS, steroids
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How is chronic gout treated?
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Serum uric acid lowering agents
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