Crystal Arthritis

Question 1

Presentation of gout

Answer 1

Acute monoarthropathy with severe joint inflammation

Question 2

Which joints can gout affect?

Answer 2

>50% = MTP joint of big toe
Ankle
Foot
Small joints of hand,
Wrist, 
Elbow
Knee

Question 3

Cause of Gout

Answer 3

Deposition of monosodium urate crystals in and near joints

Question 4

Is gout more common in males or females?

Answer 4

Males 4:1 females

Question 5

What are the causes of gout

Answer 5

Hereditary
Increased dietary purines
Alcohol excess
Diuretics
Keukaemia
Cytotoxics

Question 6

Which diseases if gout associated with?

Answer 6

CVD
HTN
DM
Chronic renal failure

Question 7

What does polarised light microscopy of the synovial fluid of a joint affected by gout show?

Answer 7

Negatively birefringent urate crystals

Question 8

What investigations would you perform if you suspected gout?

Answer 8

Polarised light microscopy of the synovial fluid
Serum urate (usually raised, may be normal)
Xray

Question 9

What x-ray findings would you get in gout?

Answer 9

Early: soft tissue swelling
Later: Punched out erosions in juxta-articular bone
Much later: loss of joint space

Question 10

1st line medical treatment of acute gout

Answer 10

High dose NSAID or COX2-i (e.g. etoricoxib 120mg/24hr PO)

Question 11

What are the contraindications to 1st line Tx of acute gout and alternative treatment

Answer 11

Peptic ulcer, heart failure, anticoagulation

Colchicine 0.5mg/6-12 hrs PO, max 6mg per course)

Question 12

Supportive treatment of gout

Answer 12

Rest, elevation, ice

Question 13

Prevention of gout (lifestyle)

Answer 13

Lose weight
Avoid: 
- prolonged fasts, 
- alcohol excess
- purine rich meats (liver, kidney)
- low dose aspirin

Question 14

When should you prescribe allopurinol for prophylaxis of gout?

Answer 14

> 1 attack in 12 months, tophi or renal stones

Wait until 3 weeks after an acute episode

Question 15

Dose of allopurinol for prophylaxis of gout

Answer 15

100mg/24hr titrating up every 2 weeks until plasma urate <0.3mmol/L

Question 16

What else do you prescribe with allopurinol and why?

Answer 16

Cover with regular NSAID (for up to 6 weeks) or colchicine (up to 6 months)

To prevent an attack triggered by allopurinol

Question 17

What should you do with the dose of allopurinol if a pt suffers an acute attack

Answer 17

If established on treatment, avoid stopping allopurinol in acute attack

Question 18

Types of Calcium pyrophosphate deposition (CPPD)

Answer 18

Acute CPP crystal arthritis (pseudogout)
Chronic CPPD (inflammatory RA-like polyarthritis)
Osteoarthritis with CPPD

Question 19

Risk factors of CPPD

Answer 19

Old age
Hyper parathyroidism
Haemachromatosis
Hypophosphataemia

Question 20

What does polarised light microscopy of the synovial fluid of a joint affected by CPPD show?

Answer 20

Weakly positive birefringent urate crystals

Question 21

What x-ray findings would you get in CPPD?

Answer 21

Soft tissue calcium deposition

Question 22

Management of acute attacks of CPPD

Answer 22

Rest
Cool packs
Aspiration and intra-articular steroids

Question 23

Prevention of acute attacks of CPPD

Answer 23

NSAIDS (+PPI) +- colchicine

Question 24

Management of chronic CPPD

Answer 24

Methotrexate and hydroxychloriquine

Question 25

Two complications of gout

Answer 25

Tophi (urate deposition) in pinna, tendons, joints

Renal disease (stones, interstitial nephritis)