The Crystal Arthropathies II Flashcards
Explain if presence of hyperuricemia is diagnostic? [1]
What level of uric acid found would indicate treatment is immediately needed? [1]
No: because 5-8% of population have elevated serum uric acid levels (>7mg/dL (0.07mg/ml))
If higher than 11mg/dL (0.11mg/ml) should be treated
What will a doppler ultrasound show in a gout patient? [5]
Doppler ultrasound
* soft tissue swelling
* increased blood flow
* vasodilation
* maintenance of joint space
* erosion outside the joint capsule
How would you treat acute gout / gout attack? [4]
NSAIDs:
* Start with highest dose for 2-3 days & taper down over 2 weeks
Colchicine:
* 2nd line (narrow therapeutic window and risk of toxicity)
Corticosteroids
* For those that can’t use NSAID or colchicine
IL1 biologicals
* Rilonacept, canakinumab, anakinra
* Reduces length of attack and reoccurrences
* Used for patients who have severe and frequent flares
How long should gout symptoms be absent for before stopping NSAID treatment for gout? [1]
2 days
Which IL1 biologicals can be used to treat acute gout? [3]
Rilonacept, canakinumab, anakinra
What type of diet is recommended for gout patients? [2]
Low purine diet AND diet high in vitamin C
Will doppler ultrasound imaging show damage in first gout attack? [1]
In the first attack however, you will not see any damage: Recurrent attacks is when damage starts to show
What x-ray findings are present in gout patients? [1]
Rat-bite erosions form on the main shaft of the bone where tendons are inserting/joint capsule is inserting
Describe a new technique for visualising gout [1]
Dual energy computed tomography (DECT): able to detect the uric acid crystals deposited in the joint & soft tissue
Describe the pathogenesis of rat-bite erosions
rat-bite erosions are due to osteoclasts eroding the bone in joints with gout
TNF-alpha, IL-1, etc will convert synovial macrophages to osteoclasts
The crystals tend to get lodged in the deeper folds of the joint capsule, meaning the osteoclasts will attack the shaft of the bone
Why are IL-1 biologicals not as useful for treating gout than RA? [1]
have to be used daily, yet with gout flares they are only used acutely for short periods of time. Only used if a patient has severe and frequent flare due to their extreme cost.
What is the treatment aim for chronic gout? [1]
A to lower the uric acid levels to get below the saturation point, preventing fluctuations in the serum
Describe how you treat chronic gout [5]
Allopurinol:
* Blocks xanthine oxidase, which is responsible from converting xanthine (which comes from purines in the diet) to urate
Febuxostat:
* non-purine selective inhibitor of xanthine oxidase
uricosuric:
* increases uric acid excretion
Probenecid:
* increases the secretion of uric acid
* fewer side effects than allopurinol.
Rasburicase:
* Catalyses conversion of uric acid to allantoin
Which ARB can be used to treat chronic gout? [1]
Losartan
Describe the pathogenesis of pseudogout [2]
Deposition of calcium pyrophosphate in and around joints onto the surface of the articular cartilage and the fibrocartilage:
- Release of calcium pyrophosphate crystals into the joint space
- followed by neutrophils, macrophages etc phagocytosing the crystals: cytokine release and inflammation.
- The crystals are not as shiny or sharp/needle like, meaning they don’t cause NETosis and the attack is much milder, with a slower onset.
Where is a common place for pseudogout to occur? [2]
Explain why [1]
Wrist and the elbow due to big amounts of fibrocartilage that can be deposited with CPP.
Describe the diagnosis of pseudogout [3]
Diagnosis of pseudogout is based on synovial fluid analysis and plain film radiography:
* mild to moderate inflammation SF analysis
* the crystals are rhomboid shaped, weakly birefringent and not as sharp/shiny or big as the MSU crystals of gout.
Ultrasound:
* calcification within the soft tissue, and articular cartilage
Which cell type is primarily involved in pseudogout CPP formation? [1]
Chondrocytes are the principle cell involved in the formation and deposition of CPP.
Which cell type is primarily involved in pseudogout CPP formation? [1]
Chondrocytes are the principle cell involved in the formation and deposition of CPP.
What would the shape, size and birefringence of pseudogout crystals be like? [3]
Shape
* rhomboid
Size:
* small (0.5 - 10 microns)
Birefringence:
* weakly positive on plane-polarised light
Which is the most commonly affected joint by pseudogout? [1]
Knee is most commonly affected joint but can affect any joint
Decribe the difference in gout and pseudogout:
- Crystal structure & appearance
- Symptoms
- Joint most commonly affected
Crystals:
* MSU very shiny under polarised light & needle like
* CPP crystals are not as shiny and are rhomboid shaped
Symptoms
* gout: has very painful acute attacks that come on sudden
* pseudo gout: more slowly progressing
Joint:
* Gout: 1st MTP joint
* Pseudogou: knee or wrist
Cholesterol crystals are sometimes seen in which MSK disease? [1]
RA
