1. Gout
MDEMO Student Presentation

2. Structure of presentation
• What is gout?
• Epidemiology
• Pathogenesis
• Clinical features
• Differential diagnoses
• Investigations
• Management
• Summary

3. What is gout?
• Crystal-induced inflammatory arthritis
• Associated with hyperuricaemia
• Usually monoarticular – ‘podagra’ of
1st
MTP joint

4. Epidemiology
• UK prevalence 0.5 - 1%
• Hyperuricaemia in 5%
• Classically affects middle-aged males
• Male:female ratio 10:1
• Menopause can precipitate gout

5. Henry VIII suffered from gout...
Podagra: acute gout in 1st
MTP
joint

6. Pathogenesis
• Serum urate ↑ after puberty & menopause
• Urate production-elimination imbalance
• Urate crystalises with ↑ concentration
• Hyperuricaemia seen with:
• ↑ age, obesity, high-protein diet, alcohol
• Positive family history

7. Pathogenesis
• Urate overproduction due to:
• Excess purine ingestion
• Excess purine synthesis
• Inborn error of metabolism (<1%)
• Impaired urate excretion by kidneys

8. Pathogenesis – purine
metabolism
Cell nucleic acids
hypoxanthine
xanthine
urate
xanthine oxidase

9. Examples of purine-rich foods

10. Inflammation
• Neutrophils
• Pro-inflammatory enzymes
• Complement activation
• Inflammatory arthritis

11. Clinical features
• Hyperuricaemia may cause:
• ‘Gout’ – acute urate synovitis
• Chronic polyarticular gout
• Chronic tophaceous gout
• Urate kidney stones

12. Soft tissue tophi

13. Clinical features of gout
• Classic acute nocturnal agonising pain
• Precipitants may be obtained from history
• 1st
MTP joint affected in >50% - podagra
• Mild pyrexia

14. Differential diagnoses
• Acute septic arthritis
• Infective cellulitis
• Chondrocalcinosis – pseudogout
(pyrophosphate crystals)

15. Investigations
• History & Examination
• Joint fluid microscopy
• Serum urate – may be raised:
Male >420 μmol/l Female >360 μmol/l
• Urea and creatinine to assess renal function

16. Negatively
birefringent
crystals:
urate
Positively
birefringent
crystals:
pyrophosphate

17. Management
• Aims
• manage symptoms
• prevent exacerbations
• reduce serum urate
• Acute and long-term strategies

18. Management – medical
• Acute: NSAIDs, colchicine, steroids
• Long-term:
Prophylaxis with xanthine oxidase
inhibitors
• allopurinol
• febuxostat – recent (2008)
• Uricosurics – e.g. probenecid
• Mammalian urate oxidase – experimental

19. Purine metabolism
Cell nucleic acids
hypoxanthine
xanthine
urate
xanthine oxidase
allopurinol febuxostat
--

20. Management – lifestyle
• Weight loss
• Diet – reduction of
• Calories
• Lipids
• Protein-rich foods
• Alcohol
...but keep hydrated

21. Gout summary
• Crystal-induced inflammatory arthritis
• Associated with hyperuricaemia
• Males >> Females
• Podagra – 1st
MTPJ symptoms
• Investigations
• Differential diagnoses
• Acute and long-term management