Crystal Related Joint Diseases Flashcards
Gout:
- Deposition of Monosodium Urate Crystals in tissue at physiologic pH
- Uric acid at pH 7.4 is in Urate form
- Two causes: Over production of urate or Decreased excretion of urate
- Loop Diuretics and Thiazide Diuretics are Not to be Used
- Pre-pubertal children and Pre-menopausal women cannot get gout
- Acute onset
- Podegra: Great toe at MPJ
- Erosions/PUNCH OUT LESIONS on bones
Purine Degradation pathway:
Purine -> Inosine -> Hypoxanthine -> Xanthine -> Uric Acid
Two reactions catalyzed by Xanthine Oxidase:
Hypoxanthine -> Xanthine
Xanthine -> Uric Acid
High fructose corn syrup and gout:
Increase Production of AMP causing increase in purines
Decreased excretion -> Lactic Acid is a by-product of metabolism and lactic acid decreases urate excretion
Drugs associated with hyperuricemia:
Cytotoxic chemotherapy Low-dose aspirin Ethanol Niacin Diuretics
Tophi:
Uric acid deposition in soft tissue
- EXTENSOR AREA OF LIMBS
- Ears
- Achilles tendon
Gout treatment:
NSAIDs to control immune response-> Indomethacin
Colchine: anti-inflammatory agent that inhibits neutrophil activation in MSU presence
Uricosuric Agents: Probenecid -> Inhibit URAT transporter bringing Uric acid back into blood
Xanthine Oxidase inhibitors: Allopurinol (Thiazide diuretics interfere with excretion of allopurinol increasing toxicity)
Calcium Pyrophosphate Dihydrate/Pseudogout:
- Deposits in hyaline and fibrocartilage of joints
- Most commonly the knee
- Larger joints affected than gout
- Also know it affects MCP joint
- Do a metabolic screening as it occurs with metabolic diseases
- If ONLY ONE OR TWO JOINTS AFFECTED ASPIRATE