Gout and Pseudogout Flashcards
What is Gout?
Inflammatory arthritis caused by deposition of monosodium urate crystals in the synovium
What is Gout caused by?
Caused by chronic hyperuricaemia (uric acid > 0.45mmol/l)
What are the risk factors for Gout?
- Decreased excretion of uric acid-
- Male, older, post-menopausal women
- drugs (diuretics, aspirin, anti-hypertensives)
- hypertension
- CKD
- lead toxicity, - Increased production of uric acid
- Dietary - alcohol, sweetners, red meat, sea food
- myeloproliferative/lymphoproliferative disorders
- severe psoriasis
- Drugs - alcohol, warfarin, cytotoxics - Family history
- Lesch Nyhan syndrome
What is the presentation of Gout?
Patients experience several days of flares and often symptom free between episodes
episode tends to develop maximal intensity in 12 hrs
main features are
- pain
- swelling
- erythema
generally presents with a single swollen hot and painful joint
What is Gouty tophi
long term subcutaneous deposits of uric acid that develop typically in the small joints (DIP) and connective tissues of hands, elbows and ears
Which joints are most affected by Gout?
- Base of big toe (metatarsalphalangeal joint) (70%)
- Wrists
- Base of thumb - carpometocarpal joints
- Large joints such as knees and ankle
What is the risk of untreated Gout?
repeated acute episodes can damage the joints resulting in a more chronic joint problem
What investigations would you do to diagnose Gout?
Joint aspiration
- exclude septic arthritis (no bacterial growth)
- needle shaped crystals
- negatively birefringent under polarised light
- monosodium urate crystals
Joint - xray
- soft tissue swelling, effusion at early stage
- punched out lesions in juxta-articular bone (with sclerotic margins and overhanging edges)
- joint space is maintained until late disease
What is the management of Acute Gout?
- 1st line:
NSAIDs + PPI (e.g. ibuprofen)
or
Colchicine (for those with renal impairment of significant heart disease)
- main side effect of colchicine is dose dependant diarrhoea - Steroids can be considered if NSAIDs and colchicine contraindicated
- Intra-articular steroid joint injections
- If patient is already taking allopurinol - should be continued
What is the indication for long term management of Gout?
- all patients should be offered long term urate lowering therapy after first attack of gout
What is the long term management/prophylaxis of Gout?
1st line?
2nd line?
- Lifestyle modifications:
reduce alcohol, lose weight, avoid purine rich foods (meat, seafoods, yeast) - Allopurinol - xanthase oxidase inhibitor - reduces uric acid levels
100mg OD starting dose, titrate until serum uric acid <300 umol/l
Colchicine cover should be considered when starting allopurinol. NSAIDs if colchicine not tolerated
2nd line: Febuxostat
When should you initiate prophylaxis
should not start allopurinal prophylaxis until acute attack has settled
What is pseudogout ?
crystal arthropathy caused by deposition of calcium pyrophosphate crystals into the synovium
Who tends to be affected by pseudogout?
- older age >60
- haemochromatosis
- hyperparathyroidism
- low magneiusm, low phosphate
- acromegaly
How do you diagnose pseudogout?
- aspiration of synovial fluid
- no bacterial growth
- calcium pyrophosphate crystal
- rhomboid shaped crystals
- positively birefringent under polarised light - x-ray
- chondrocalcinosis - thin white line in the middle of joint space (along the meniscus) due to calcium deposition
- Osteoarthritis changes (LOSS)
