Crystal Arthropathies

Question 1

What is gout?

Answer 1

The formation of uric acid crystals in and around the joints

Question 2

What causes gout? (2)

Answer 2

Under excretion of uric acid: diabetes, CKD, drugs (aspirin, thiazides), dehydration
Overproduction of uric acid: alcohol, purine-rich foods (red meat, shellfish), fructose-sweetened drinks, increased cell turnover

Question 3

What are the clinical presentations of gout? (3)

Answer 3

Painful, tender swollen joint that’s red and warm
Commonly affects 1st metatarsal joint, feet & ankles
May have fever

Question 4

Describe a typical gout patient (4)

Answer 4

Obese man with toe pain who had an alcohol and shellfish binge last night

Question 5

How would you investigate gout? (4)

Answer 5

Aspirate joint (rule out septic arthritis)
Polarised light microscopy = negatively birefringent needle-shaped crystals
Bloods: raised WBC, ESR and urate
X-ray: early = soft tissue swellings, later = rat bite/ punched out erosions

Question 6

How would you treat gout non-pharmacologically? (4)

Answer 6

Lifestyle changes:

• Weight loss
• Less alcohol
• Hydration
• Dairy products (have protective effect)

Question 7

How would you treat acute gout? (4)

Answer 7

• NSAID
• If c/i = colchicine
• Steroids may be used
• Rest + elevate joint, ice packs may help

Question 8

How would you manage gout in the long term?

Answer 8

Allopurinol (if c/i febuxostat)

Question 9

When would you start prophylactic treatment in a pt being treated for acute gout?

Answer 9

After 3 weeks as allopurinol can trigger another attack

Question 10

Which groups are more likely to be affected by gout?

Answer 10

Middle-aged men

Question 11

Which groups are more likely to be affected by pseudogout?

Answer 11

Older females (7th decade +)

Question 12

What type of crystals are found in gout? (3)

Answer 12

Negatively birefringent, needle-shaped monosodium crystals

Question 13

What is pseudogout?

Answer 13

Accumulation of calcium pyrophosphate dihydrate crystals (CPPD) within joints

Question 14

What are the causes of pseudogout? (6)

Answer 14

Elderly
Direct trauma
Illness
Hypothyroidism
Hyperparathyroidism
Surgery

Question 15

What are the clinical presentations of pseudogout? (4)

Answer 15

Symmetrical RA-like polyarthritis and synovitis
Hot, swollen, tender, painful and red joint
Fever
Joint stiffness

[Knee commonly affected]

Question 16

How would you investigate pseudogout? (4)

Answer 16

Joint aspiration
Polarised light microscopy = positively birefringent rhomboid-shaped crystals
X-ray: chondrocalcinosis
Bloods: raised WBCs and calcium

Question 17

How would you treat acute pseudogout?

Answer 17

NSAIDs (+PPi) and colchicine

Cool packs, rest, aspiration, steroids

Question 18

What type of crystals are found pseudogout? (3)

Answer 18

Positively birefringent, rhomboid-shaped calcium pyrophosphate crystals