Crystal Arthritis - Gout Flashcards
What is Gout?
Crystal arthropathy, associated with blood uric acid levels.
Important Differential Diagnosis of Gout.
Septic Arthritis.
Risk Factors of Gout (7).
- Male.
- Obesity.
- High Purine Diet (e.g. Meat, Seafood).
- Alcohol.
- Diuretics.
- Existing CVD/Kidney Disease.
- Family History.
Clinical Features of Gout.
Single Acute Hot Painful Swollen Joint.
What are Gouty Tophi?
Subcutaneous deposits of uric acid, typically affecting the small joints and connective tissues of the hands, elbows and ears.
Which joints are most affected by gout in the hands?
DIPs.
Which joints are typically affected by gout? (3)
- Base of the Big Toe - Metatarsophalangeal joint (70% of 1st presentations) - “podagra”.
- Wrist.
- Base of the Thumb - Carpometacarpal Joint.
Clinical Presentation of Gout.
Flare - episodes lasting several days and reaching maximal intensity within 12 hours but symptom free between episodes.
Aetiology of Gout (2).
- Urate crystals are deposited in the joint.
2. Chronic Hyperuricaemia - Uric Acid > 0.45 mmol/L.
What can increased production of uric acid? (3)
- Myeloproliferative/Lymphoproliferative Disorder.
- Cytotoxic Drug.
- Severe Psoriasis.
What can decrease excretion of uric acid? (3)
- Drugs - Diuretics.
- Chronic Kidney Disease.
- Lead Toxicity.
What is Lesch-Nyhan Syndrome?
HGPRTase Deficiency - X-linked Recessive in boys : gout, renal failure, neurological deficits.
Diagnosis of Gout (2).
- Clinical Diagnosis + Aspiration of Fluid from Joint.
2. EXCLUDE SEPTIC ARTHRITIS.
What will Aspirated Fluid show in Gout? (4)
- No bacterial growth.
- Needle-Shaped Crystals.
- Negatively Birefringent of Polarised Light.
- Monosodium Urate Crystals.
What will an X-Ray show in Gout? (3)
MELP :
- Maintenance of joint space.
- Joint Effusion (Early Sign).
- Lytic Lesions in Bone.
- Punched out Erosions that have sclerotic borders with overhanging edges.
Investigation of Gout.
Uric acid levels should be checked after settling down (2 weeks later); during the flare, it can be high, normal or low.
How is an acute flare of Gout treated? (3)
1st Line - NSAIDs (maximum-dose for 1-2 days after settling) with PPI.
2nd Line - Colchicine (anyone with renal impairment or significant heart disease); side effect is GI Upset (Diarrhoea) but is dose-dependent.
3rd Line - Steroids.
What prophylaxis can be used against gout? (2)
- Allopurinol (after acute attack settles) - Xanthine Oxidase Inhibitor (reduces uric acid level) - Colchicine cover.
- Lifestyle Changes - lose weight, stay hydrated, minimise alcohol and purine foods.
