Gout

Question 1

Gout is characterised by what 4 factors?

Answer 1

1. Hyperuricaemia and deposition of urate crystals causing attacks of acute inflammatory arthritis.
2. Tophi around the joint and possible joint destruction.
3. Renal glomerular, tubular and interstitial disease.
4. Uric acid urolithiasis.

Question 2

What body parts are most commonly affected?

Answer 2

The big toe, foot, ankle, knee, fingers, wrist and elbow. But it can affect any joint.

Question 3

Who is most affected?

Answer 3

· More common in men.

· Rare in pre-menopausal women.

Question 4

What is the pathophysiology of gout?

Answer 4

· Gout develops spontaneously.
· Gout most commonly affects the first metatarsophalangeal joint and OA joints.
· Urate crystals in the joint interact with phagocytes and trigger an acute inflammatory response.

Question 5

What is the aetiology of gout?

Answer 5

· Causal relationship between hyperuricaemia (high urate level) and gout.

· Urate is a metabolite of purines (adenine and guanine) and the ionised form of uric acid.

· Hyperuricaemia doesn’t always lead to gout.

· Hyperuricaemia is due to impaired renal excretion:

• Under-excretion of urate in 90% of cases.
• Over-production of urate in 10% of cases.

Question 6

What risk factors are associated with gout?

Answer 6

· Older age.
· Male. 
· Consumption of seafood, meat and alcohol (especially beer) - high purine content. 
· Haematological cancer and chemotherapy (high cell turnover rate). 
· Diuretic use. 
· Ciclosporin or tacrolimus use. 
· Obesity.
· Insulin resistance. 
· Hypertension.

Question 7

List the typical signs and symptoms of gout.

Answer 7

· Rapid-onset severe pain.
· Joint stiffness.
· Most common affected joints are in the feet.
· Swelling and joint effusion.
· Tenderness.
· Tophi - nodular deposits of uric acid crystals in soft tissues of the body.
· Erythema and warmth.

Question 8

What investigations would you request if you suspected a patient had gout?

Answer 8

· Arthrocentesis with synovial fluid analysis:

• Not always needed if confident but will confirm the diagnosis.
• Excludes septic arthritis and differentiates with pseudo-gout.

· Uric acid level - >416micromol/L in men and >360micromol/L in women.

· X-ray of affected joint.

Question 9

Suggest some differentials.

Answer 9

· Pseudogout (calcium pyrophosphate deposition disease).
· Septic arthritis. 
· Trauma. 
· RA.
· Reactive arthritis. 
· Psoriatic arthritis.

Question 10

What differentiates pseudogout from gout?

Answer 10

Pseudogout can be an identical presentation

but it is more likely to affect wrist and knee joints.

Question 11

What are the treatment options for acute gout?

Answer 11

1st - NSAID (e.g. naproxen).
2nd - Colchicine.
3rd - Corticosteroids.

Question 12

What are the treatment options for recurrent gout?

Answer 12

1st - Xanthine oxidase inhibitor - ALLOPURINOL.
2nd - Probenecid or sulfinpyrazone.
3rd - IV pegloticase.

Plus - Suppressive therapy.

Question 13

Suggest some complications.

Answer 13

· Nephrolithiasis.

· Acute uric acid nephropathy.

Question 14

When does acute uric acid nephropathy occur?

Answer 14

Occurs most commonly in patients treated with cytotoxic agents.

Occurs with very high uric acid levels.