Crystal arthropathies

Question 1

What molecule is innvolved in gout

Answer 1

Uric acid

Question 2

What % of the population have gout

Answer 2

1

Question 3

In which sex is gout more common

Answer 3

Men

Question 4

What crystals are deposited in gout, and where

Answer 4

Monosodium urate crystals

Soft tissues

Question 5

What happens if gout is left untreated

Answer 5

Joint destruction

Renal damage

Question 6

At what age does uric acid rise peak in men and women

Answer 6

men– puberty

women– menopause

Question 7

What is the peak age of onset of gout in men and women

Answer 7

men– 4th to 6th decade

women– 6th to 8th decade

Question 8

How many years are uric acid levels higher before gout onset

Answer 8

20

Question 9

What triggers a gout attack

Answer 9

Uncoated crystals or a sudden change in concentration

Question 10

What are uric acid crystals usually coated in

Answer 10

Serum proteins

Question 11

Can urate crystals cause gout attack if they are found in the synovial membrane

Answer 11

No

Question 12

Which joints does gout usually affect

Answer 12

Small, lower extremity joints

Question 13

What is podagra

Answer 13

Inflammation of first MTP joint

Question 14

Describe the onset of a gout attack

Answer 14

begins suddenly

maximum intensity within 8-12 hours

Question 15

Name some joints commonly affected by gout

Answer 15

Knee, ankle, toes, elbow, sometimes shoulder

Question 16

How does the joint appear/ feel in gout

Answer 16

Red, hot, tender, pain starts acuteley and usually at night

Question 17

How long does first attack of gout take to resolve if untreated

Answer 17

< 2 weeks

Question 18

In what % of gout does it initally present as polyarticular athritis

Answer 18

10

Question 19

What drug is commonly associated with polyarticular athritis upon first presentation of gout

Answer 19

Thiazide diuertic (esp old ladies)

Question 20

What can happen if gout is left untreated (5)

Answer 20

• Attacks become polyarticular
• More proximal and upper extremity joints involved
• Attacks more frequent and last longer
• Symmetrical, chronic polyarticular athritis
• Can affect other synovial structures

Question 21

What are tophi

Answer 21

Urate crystals in soft tissue

Question 22

In what % of untreatedd gout patients to tophi appear

Answer 22

50%

Question 23

When do tophi develop

Answer 23

After 10 years

Question 24

Uric acid is the end stage by product of the metabolism of which molecule

Answer 24

Purine

Question 25

How do humans remove uric acid

Answer 25

Via renal excretion and faeces

Question 26

What value is 'saturation' of serum urate

Answer 26

6.8mg/dL

Question 27

What may be develop if excretion is insufficient to maintain serum urate levels below saturation

Answer 27

Hyperuricemia

Question 28

Is over production of urate or under excretion more common in gout

Answer 28

Over excretion (90%)

Question 29

Describe the 'pathway' of risk factors leading to gout

Answer 29

- Elevated purine sources/ general risk factor lead to increased purines - This leads to xanthine - This leads to hyperuricemia - This leads to reduced renal clearance

Question 30

What are some causes of elevated purine sources

Answer 30

- Catabolism of purines - Tumour lysis syndrome - Diet

Question 31

What foods are high in purines

Answer 31

Beef, pork, lamb, seafood, beer, alcohol

Question 32

Risk factors for gout

Answer 32

``` Male Age, Obesity Kidney disease Ethnicity Polymorphisms ```

Question 33

What are the risks of hyperuricemia

Answer 33

``` Joint inflammation Kidney/ bladder stones Nephropathy CV disease Met. syndromes ```

Question 34

What can cause decreased renal clearance

Answer 34

Drugs like aspirin | Fructose

Question 35

What can cause under-excretion of uric acid

Answer 35

Renal insufficiency Dehydration Diuretics

Question 36

What must serum levels of urate be higher than for a gout diagnosis

Answer 36

5.88mg/dL

Question 37

What score out of 11 is required for a diagnosis of probable gout

Answer 37

6

Question 38

What, combined with score, is required to turn diagnosis from probable to definite gout

Answer 38

Urate crystals during acute attack

Question 39

What score is required for a diagnosis of 'not gout'

Answer 39

<4

Question 40

What are some differentials of gout

Answer 40

``` RA Pseudogout Psoriatic arthritis Septic arthritis Reactive arthritis ```

Question 41

How is synovial fluid used for a gout diagnosis

Answer 41

- Inflammatory - WBC >2000 - Predominance of polymorphonucleur neutrophils

Question 42

How do urate crystals appear in synovial fluid under polarising light

Answer 42

Needle like | High negatively birefringent

Question 43

Is the presence of hyperuricemia diagnostic

Answer 43

No

Question 44

Serum uric acid levels above what value should be treated

Answer 44

Above 11mg/dL

Question 45

What abnormalities would be seen in a person with gout on x-ray or ultrasound

Answer 45

- Soft tissue swelling - Increased blood flow - Maintenance of joint space - Erosion outside joint capsule. These erosions have overhanging edges called rat bites

Question 46

What does DECT stand for

Answer 46

dual energy computed tomography

Question 47

What abnormalities can be detected on a DECT scant

Answer 47

- Uric acid crystal deposits in all late stage patients, and in 60% of early

Question 48

What are the clinical uses of DECT

Answer 48

- Measure MSU volume - Changes in actual MSU treatment - Predict gout flare

Question 49

What does MSU stand for

Answer 49

monosodium urate

Question 50

How do tophaceous deposits lead to bone erosion

Answer 50

- MSU crystals surrounded by granulomatous tissue reaction - Produces pro-inflammatory cytokines - Stimulates osteoclasts via RANKL

Question 51

What pro-inflammatory cytokines are involved in gout

Answer 51

IL1, TNF, IL6

Question 52

4 ways to treat an acute attack of gout

Answer 52

- NSAID - Colchicine - Coticosteroids - IL1 biologicals

Question 53

When should NSAIDS be stopped

Answer 53

When symptoms absent for 2 days

Question 54

Why is colchicine second line

Answer 54

Narrow theurapeutic window | Toxicity risk

Question 55

Name 3 IL1 biologicals

Answer 55

Rilonacept Canakinumab Anakinra

Question 56

When are IL1 biologicals used

Answer 56

For patients who have severe and frequent flares

Question 57

Name 3 drugs used in the chronic management of gout

Answer 57

- Allopuinol - Probenecid - Rasburicase

Question 58

How does allopurinol work

Answer 58

Blocks xanthine oxidase reducing generation of uric acid

Question 59

How does probenecid work

Answer 59

Increases uric acid secretion, fewer significant adverse effects

Question 60

How does rasburicase work

Answer 60

Catalyses conversion of uric acid to allantoin

Question 61

What is the proper name for pseudogout

Answer 61

Calcium pyrophosphate deposition disease/ chondrocalcinosis

Question 62

What is psudogout

Answer 62

The acute deposition of calcium pyrophosphate crystals in and around joints

Question 63

What are the features of pseudo-osteoathritis

Answer 63

Osteophytes and soft tissue calcification seen on radiographs

Question 64

What is the underlying pathophysiology of pseudogout (in brief)

Answer 64

- Release of CPPD crystals into joint space - Phagocytosis of crystals by monocyte-macrophages or neutrophils - Release of cytokines causing inflammation

Question 65

What is the joint most commonly affected by pseudogout

Answer 65

Knee

Question 66

What can trigger an acute attack of pseudogout

Answer 66

Trauma | Rapid reduction of serum calcium conc.

Question 67

How does synovial fluid appear in pseudogout

Answer 67

- Mild to moderate inflammation | - Rhomboid shaped, weakly birefringent crystals

Question 68

How is pseudogout treated

Answer 68

Intra-articular corticosteroids | NSAIDs