Gout & Pseudogout Flashcards
What is gout?
Hyperuricaemia and deposition of monosodium urate crystals causing attacks of acute inflammatory arthritis, gouti tophi, urate nephropathy and uric acid nephrolithiasis.
Discuss the pathophysiology of gout
- Uric acid exists as urate at physiological pH
- High levels of urate causes super-saturation and crystal formation
- Monsodium urate cystals deposit in joint and cause inflammatory response
What crystals are deposited in joints in gout?
Monosodium urate crystals
State some risk factors for gout
- Age >40yrs
- Male
- Obesity
- High purine diet (e.g. meat, seafood)
- Alcohol (especially beer)
- Diuretics
- Existing cardiovascular disease (e.g. dyslipidaemia, coronary artery disease, CHF)
- Existing kidney disease
- Family history
- Diabetes
- Smoking
- High fructose intake
State some symptoms of gout
- Joint pain
- Joint swelling
- Joint stiffness (which is worse after rest)
- Hot joint
- Joint tenderness
Typically presents with a single acute, hot, swollen and painful joint (it can affect more than one joint)
What might you find on clinical examination of someone with gout?
Joint is:
- Swollen
- Hot
- Tender
- Gouty tophi
What is gouty tophi?
Gouty tophi are subcutaneous deposits of urica acid typically affecting small joints and connective tissue of hands, elbows and ears. DIP are most affected in hands
Which joints are typically affected by gout?
- Metatarsophalangeal joint of great toe
- Wrists
- Carpometacarpal joint of first digit (thumb)
- Also affect large joints e.g. knee & ankle
Which joint is commonly involved in the first presentation of gout?
1st metatarsophalangeal joint
(podagra)
What is podagra?
Gout affecting the foot, typically the 1st metarsophalangeal joint
What are your differentials for someone presenting with gout-like symptoms?
Which one MUST you rule out
- Septic arthritis *MUST RULE OUT
- Pseudogout
What investigations would you do if you suspect gout, inlcude:
- Bedside
- Bloods
- Imaging
*Where appropriate, justify each
Bedside
- Arthrocentesis
Bloods
- FBC: rasied WCC in infection
- U&Es: urate nephropathy
- CRP: inflammation
- Uric acid level
Imaging
- X-ray of joint
Describe what the aspirated fluid will most likely look like if a pt has septic arthritis
- Septic arthritis: purulent
- Gout: cloudy
When you send aspirated fluid to the lab, what will it show if the pt has gout?
- No bacterial growth
- Needle shaped crystals
- Negative birefringement of polarised light
- Monsodium urate cyrstals
What might you see on x-ray of pt with gout?
- Typically joint space is maintained
- Lytic lesions in bone
- Punched out erosions
- Punched out erosions can have sclerotic borders with overhanding edges