Crystal Arthropathy

Question 1

What is the main cause of the hyperuricaemia in gout?

Answer 1

Reduced efficiency of renal urate clearance

Question 2

What are the causes of hyperuricaemia?

Answer 2

• Overproduction: malignancy, severe exfoliative psoriasis, drugs (ethanol, cytotoxic drugs), inborn errors of metabolism and HGPRT deficiency
• Under excretion: renail impairment, hypertension, hypothyroidism, drugs (alcohol, low dose aspirin, diuretics and cyclosporins), exercise, starvation, dehydration and lead poisoning

Question 3

What are the features of Lesch Nyan Syndrome?

Answer 3

• HGPRT deficiency
• X linked recessive
• Intellectual disability
• Aggressive and impulsive behaviour
• Self mutilation
• Gout
• Renal disease

Question 4

Are males or females more likely to get gout?

Answer 4

Males

Question 5

How can gout be investigated?

Answer 5

-Aspiration of the joint

Question 6

What can be seen on an aspiration of gout under the microscope?

Answer 6

Negatively birefringent needle shaped crystals

Question 7

How can an acute episode of gout be managed?

Answer 7

• NSAIDs
• Colchicine
• Steroids

Question 8

In what cases should a first episode of gout be treated?

Answer 8

• Single episode of polyarticular gout
• Trophaceous gout
• Urate calculi
• Renal insufficiency

Question 9

Which medicines can be used to lower uric acid levels?

Answer 9

• Xanthine oxidase inhibitor e.g. allopurinol
• Febuxostat
• Uricosuric agents e.g. sulphinpyrazone, probenecid and benzbromarone
• Canakinumab

Question 10

What are the rules for lowering uric acid levels?

Answer 10

• Wait until the acute attack has settled
• Use prophylactic NSAIDs or low dose colchicine/steroids until urate level is normal
• Adjust allopurinol dose according to renal function

Question 11

What are the most commonly affected joints in gout and pseudogout?

Answer 11

Gout - big toe

Pseudogout - knees

Question 12

What are the possible causes and triggers of pseudogout?

Answer 12

• Causes: familial, metabolic and idiopathic

- Triggers: trauma and intercurrent illness

Question 13

What can be seen on the aspiration of pseudogout under the miscroscope?

Answer 13

Positively birefringement rhomboid crystals - calcium pyrophosphate

Question 14

What is the management for pseudogout?

Answer 14

• NSAIDs

- I/A steriods

Question 15

What are the presenting features of polymyalgia rheumatica?

Answer 15

• Females
• Usually > 70yrs
• Sudden onset of shoulder +/- pelvic girdle stiffness
• ESR usually > 45
• Anaemia
• Malaise, weight loss, fever and depression
• Occasionally arthralgia/synovitis

Question 16

Which features suggest a diagnosis of polymyalgia rheumatica?

Answer 16

• Compatible history
• Age>50
• ESR>50
• Dramatic steroid response

Question 17

What is the differential diagnosis for polymyalgia rheumatica?

Answer 17

• Myalgic onset inflammatory joint disease
• Underlying malignancy e.g. multiple myeloma, lung cancer
• Inflammatory muscle disease
• Hypo/hyperthyroidism
• Bilateral shoulder capsulitis
• Fibromyalgia

Question 18

What is the treatment of polymyalgia rheumatica?

Answer 18

• Prednisolone 15mg per day initially
• 18-24 month course
• Bone prophylaxis