Gout Flashcards
What is gout?
Gout is a potentially disabling and erosive inflammatory arthritis cused by the deposition of monosodium urate (Uric acid) crystals into joints and soft tissue
Who is most at risk of developing gout?
People between the ages of 20 and 80
It is more common in men than women
It is very rare in women before the menopause
What are the 2 pathways of developing hyperuricaemia?
Increased uric acid production
Reduced uric acid excretion
What are some causes of increased uric acid production?
- Inherited enzyme deficiency (Lesch Nyhan)
- Myeloproliferative or lymphoproliferative disorders
- Psoriasis
- High alcohol intake
- High dietary purine intake (Red meat, seafood, corn syrup)
What are some causes of reduced uric acid excretion?
- Chronic renal impairment
- Volume depletion (e.g. heart failure)
- Hypothyroidism
- Diuretics
- Cytotoxics (e.g. ciclosporin)
Where does uric acid in the body come from?
From purines gained from:
DNA metabolism
Dietary intake (Red meat, seafood)
Describe the breakdown of purines into uric acid
Purine =>
Hypoxanthine =>
Xanthine =>
Plasma urate =>
Uric acid
What uric acid level is described as hyperuricaemia?
> 0.42 mmol/L
How does hyperuricaemia lead to gout?
Hyperuricaemia =>
Precipitation of urate crystals in joints =>
Complement activation and phagocytosis =>
Neutrophil chemotaxis =>
Release of lysosomal enzymes, LTB4 and prostaglandins =>
Phagocytosis leads to release of IL-1, TNF. IL-6 and IL-8 =>
Tissue injury and inflammation
How does acute gout present?
Monoarthropathy with severe pain and hot, swollen joints
Abrupt onset which occurs overnight
What are the most commonly affected joints in gout?
MTP joints
Ankle joints
Knee joints
How long will symptoms of an acute gout flare up last without treatment?
10 days
How long will symptoms of an acute gout flare up last with treatment?
3 days
What is chronic topahaceous gout?
Chronic joint inflammation in gout and is often associated with diuretics
How will chronic tophaceous gout usually present?
This results in granulomatous tophi formation, containing eosinophilic debris and inflammation
These are usually painless
What tests are usually required in gout diagnosis?
Serum uric acid
Bloods
Polarised microscopy of synovial fluid
X-ray
What will be shown on blood tests in gout?
Raised inflammatory markers
What will be seen on polarised microscopy of synovial fluid in gout?
Needle-shaped, negative birefringent crystals
What will X-ray show in long-standing gout?
Joint erosion
What lifestyle modifications are required in gout?
Reduction of alcohol intake
Reduction of purine intake
How are acute gout flare-ups treated?
NSAIDs
Colchicine
Steroids
What medication can be given to prevent further flare-ups of gout?
Xanthine oxidase inhibitors (Allopurinol, febuxostat)
Uricosuric drugs (sulfinpyrazone, probenecid, benzbromarone)
What are some examples of Xanthine oxidase inhibitors?
Allopurinol
Febuxostat
What are some examples of uricosuric drugs?
Sulfinpyrazone
Probenecid
Benzbromarone
