Crystal arthropathies Flashcards
What is gout?
A crystal arthropathy characterised by chronically high blood uric acid levels
What is the pathophysiology of gout?
Urate crystals are deposited in the joints, causing them to become hot, swollen and painful
What are gouty tophi?
They are subcutaneous deposits of uric acid, typically affecting the small joints and connective tissues in the hands, elbows and ears
Which joints are the most affected in the hands?
DIPs
How does it typically present?
With a single acute hot, swollen and painful joint
What is an important differential for gout?
Septic arthritis - life threatening
Risk factors for gout
Male Obesity High cholesterol Existing CVD/ renal disease Diet high in uric acid - meat and seafood Alcohol Diuretics Family history
What are the typical joints affected
Base of big toe (metatarso-phalangeal joint) DIPs in hands Wrists Base of thumb (carpometacarpal joint) Knee Ankle
How is gout diagnosed?
Clinically by aspiration of fluid from the joint
Aspirated fluid in gout will show
Negative for bacterial growth
Needle shaped crystals
Negative birefringent of polarised light
Monosodium urate crystals
On joint xray for gout, you will see:
Typically the joint space is maintained
Lytic lesions in the bone
Punched out lesions
Erosions can have sclerotic borders with overhanging edges
Management of gout:
First line: NSAIDS e.g. ibuprofen
Second line: colchicine
Third line: steroids
When are NSAIDs contraindicated?
In patients with nsaid allergy
Asthma
Hx of GI bleeding/ ulcers
Side effects of colchicine
GI upset
Diarrhoea
How can the side effects of colchicine be combatted?
The effects are dose dependent - start on low dose to cause less upset
When is prophylaxis against gout indicated?
AFTER the acute attack
What is the prophylaxis for gout
Allopurinol
What is allopurinol
Xanthine oxidate inhibitor - it reduces uric acid levels
What other advice would you give to a patient with gout as part of their management?
Lifestyle changes can reduce risk of developing gout/ acute attacks
Reduce alcohol and purine-based food intake (meat and seafood)
Drink more water
Exercise
Lose weight
When should allopurinol be stopped?
Never - unless SEs are intolerable once started can be continued through an acute attack.
But do NOT start it for the first time during an acute attack
What dose of colchicine is given?
500micrograms 2-4 times a day until symptoms are relieved. 6mg max course
