Crystalline arthropathies

Question 1

gout, serume urate, hyperuricemia

Answer 1

• Gout = Inflammatory arthritis developing as a consequence of urate deposition in the joint
• Serum urate = formed in process of purine metabolism/degradation
• Hyperuricemia = serum urate values in excess of 6.8 mg/dl

Question 2

Joints that are affected by acute gouty arthritis

Answer 2

• 1st MTP (podagra) - 90%
• mid-food
• ankle
• heel
• knee
• wrist
• etc

Question 3

Gout - stages

Answer 3

1. Asymptomatic hyperuricemia
   
   • elevated serum urate with no clinical manifestation of gout
2. Acute flares (if you have a first gout attack, you will have a second)
   
   • acute inflammation in the joint caused by urate crystallization
3. Intercritical segments
   
   • interval between acute flares
4. advanced gout
   
   • long-term gouty complications of uncontrolled hyperuricemia

Question 4

what is the key enxyme in purine degradation to uric acid

Answer 4

• Xanthine oxidase catalyzes the final conversion to uric acid
• Therapeutic target for gout

Question 5

Risk factors for the development of gout: DRUGS

Answer 5

• Diuretics = leads to INcrease uric acid reabsorption
• Low dose aspirin = increase in mean serum urate and decrease uric acid clearance
• Niacin, pyrazinamide, ethambutol = gout observed at higher incidence

Question 6

Rick factors for development of gout: TRANSPLANT PTS

Answer 6

• CYCLOSPORINE USE: AZATHIOPRINE = ALLOPURINOL INTERACTION –> leads to GOUT ATTACKS

Question 7

Gout - what compnay does it keep.

Answer 7

• Obesity
• metabolic syndrome
• DIABETES MELLITUS
• Heart failure
• hyperlipidemia
• hypertension

Question 8

Diagnosing gout

Answer 8

• Serum urate (may be normal or elevated with joint symptoms)
• Hx and Px
• SYNOVIAL FLUID ANALYSIS = GOLD STANDARD
  
  • MSU crystals visible with compensated polarized light
• Differentials:
  
  • CPPD (pseudogout), septic arthritis

Question 9

Radiographs in gout

Answer 9

• Acutely - often only soft tissue swelling
• Chronic
  
  • overhanging edge
  • erosions with demarcated round deficits with sclerotic margins
  • very destructive
  • (PRESERVED JOINT SPACES)

Question 10

termination of acute flare

Answer 10

• Resolution of acute flare by controlling crystal-induced inflammation and pain
  
  • NOT A CURE FOR GOUT
• NSAIDs, Colchicine, steroids/ACTH
  
  • steroids = resolution in 24-48 hours
• Critical issues are:
  
  • rapid initiation of therapy
  • appropriate duration of therapy (2 week process)

Question 11

Colchicine

Answer 11

• drug interactions with cyclosporine, statins, MACROLIDES
• can cause local tissue necrosis
• USE OF IV FORMULATION CONTROVERSIAL AND SHOULD BE USED WITH EXTREME CAUTION

Question 12

treating hyperuricemia and preventing disease progression

Answer 12

• Goals:
  
  • lower urate <6 mg/dL (6-point-oh to save the toe)
• therapy should be lifelong (intermittent therapy is bad)
• ALLOPURINOL = blocks conversion of hypoxanthine to xanthine to uric acid