Gout and Pseudogout Flashcards
gout pathophysiology
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.
gout risk factors and clinical features
Risk Factors Male Obesity High purine diet (e.g. meat and seafood) Alcohol Diuretics Existing cardiovascular or kidney disease Family history
Typical 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.
It typically presents with a single acute hot, swollen and painful joint. The obvious and extremely important differential diagnosis is septic arthritis.
diagnosis of gout
exclude septic arthritis
aspiration: No bacterial growth Needle shaped crystals Negative birefringent of polarised light Monosodium urate crystals
Xray of affectedjoint
xray of gout
Typically the space between the joint is maintained
Lytic lesions in the bone
Punched out erosions
Erosions can have sclerotic borders with overhanging edges
gout management of acute flare
acute flare:
NSAIDs (ibuprofen)
cholchicine (second line / inappropriate for NSAIDs / renal impairment) side effect is GI upset like diarrhoea.
steroids (third line)
allopurinol should not be given within 4-6 weeks of an acute episode as it may precipitate another episode of acute gout.
gout prophylaxis
allopurinol (xanthine oxidase inhibitors) reduces the uric acid levels
lifestyle changes. weight loss, minimise consumption of alcoho, purine based food.
do not initiate allopurinol until after acute attack is settled.
pseudogout
crystal arthropathy
caused by calcium pyrophosphoate crystals
deposited in the joint causing joint problems
AKA chondrocalcinosis
associated with haemachromatosis
pseudogout clinical feautres
older adult with a hot, swollen, stiff, painful knee. Other joints that are commonly affected are the shoulders, wrists and hips.
can be a chronic condition and affect multiple joints. It can also be asymptomatic and picked up incidentally on an xray of the joint.
pseudogout diagnosis
excluse septic arthrits
- aspirate for synovial fluid: No bacterial growth Calcium pyrophosphate crystals Rhomboid shaped crystals Positive birefringent of polarised light
-xray:
thin white line in the middle of the joint space caused by calcium deposition
L – Loss of joint space
O – Osteophytes
S – Subarticular sclerosis
S – Subchondral cysts
pseudogout management
chronic asymptomatic- no action
symptoms resolve over week NSAIDs Colchicine Joint aspiration Steroid injections Oral steroids
severe case: joint washout (arthrocentesis)
mono arthritis
consider septic arthritis!
don’t start or stop allopurinol or uricosurics during acute gout
aspirate a mono arthritis
acute gout
lasts 3 days
treatment is NSAIDs (naproxen)and coltechiaen
short term oral steroids (prednisolone)
once septic arthritis is excluded then give IA steroid injection.
if never been on allopurinol then don’t start this until the acute gout has resolved because this will worsen the symptoms. you should wait 2-3 weeks
crystal arthritis
monosodium urate monohydrate= gout
calcium pyrophosphate= pseudogout
hyroxyapetitie
oxalate
snthetic glucocorticoids
gout risk factors
risk factor for CVS obsess, elderly male excess alcohol diuretics- CCF, HTN renal insufficiency fhx
rare in pre-menopausal women (oestrogen)
crystals neutrophil phagocytosis = release of cytokine = neutrophil chemostaxis - inflammation
purine
diet purines (300-600mg/day)
cell break down (e.g. if malignancy then there is a higher production)
= all this is ‘total purines’ which is broken down into an uric acid pool and excreted in faeces and urine.
