Gout Flashcards
What is gout?
Gout is a type of crystal arthropathy associated with chronically high blood uric acid levels. Urate crystals are deposited in the joint causing it to become hot, swollen and painful.
Gouty tophi are subcutaneous deposits of uric acid typically affecting the small joints and connective tissues of the hands, elbows and ears. The DIP joints are most affected in the hands. It typically presents with a single acute hot, swollen and painful joint. The obvious and extremely important differential diagnosis is septic arthritis.
Risk factors?
Male
Obesity
High purine diet (e.g. meat and seafood)
Alcohol
Diuretics
Existing cardiovascular or kidney disease
Family history
Typical affected joints ?
Base of the big toe (metatarsophalangeal joint)
Wrists
Base of thumb (carpometacarpal joints)
Gout can also affects large joints like the knee and ankle.
Diagnosis?
Gout is diagnosed clinically or by aspiration of fluid from the joint. Excluding septic arthritis is essential as this is a potential joint and life-threatening diagnosis.
Aspirated fluid will show:
No bacterial growth
Needle shaped crystals
Negatively birefringent of polarised light
Monosodium urate crystals
Joint x-ray
Typically the space between the joint is maintained
Lytic lesions in the bone
Punched out erosions
Erosions can have sclerotic borders with overhanging edges
Management?
During the acute flare:
NSAIDs (e.g. ibuprofen) are first-line
Colchicine second-line
Steroids can be considered third-line
Colchicine is used in patients that are inappropriate for NSAIDs, such as those with renal impairment or significant heart disease. A notable side effect is gastrointestinal upset. Diarrhoea is a very common side effect. This is dose-dependent meaning lower doses cause less upset than higher doses.
Prophylaxis?
Allopurinol is a xanthine oxidase inhibitor used for the prophylaxis of gout. It reduces the uric acid level.
Lifestyle changes can reduce the risk of developing gout. This involves losing weight, staying hydrated and minimising the consumption of alcohol and purine-based food (such as meat and seafood).
