Crystal Arthropathy Flashcards
Define Crystal Arthropathies?
Any arthropathy involving deposition of mineralised material in joints or periarticular tissue
I.e. Gout & Pseudogout
What is deposited in joints in Gout?
Monosodium Urate, crystals of Uric Acid
Describe the physiological passage of urate?
2/3rd plasma urate comes from purine breakdown
1/3rd comes from diet
Its then cleared mostly by the kidneys and some by the biliary tract
What are some causes of over-production of Urate?
- Malignancy
- Severe Exfoliative Psoriasis
- Drugs e.g. Alcohol
- HGPRT deficiency
- Inborn Metabolic errors
What are some causes of under-excretion of urate?
Renal Impairment (main cause for gout)
HYpertension
Hypothyroidism
Drugs e.g. Aspirin, alcohol, diuretics & cyclosporin
Lead poisoning
Exercise, starvation or dehydration
What is HGPRT deficiency also known as?
Lesch Nyan Syndrome
An X linked recessive disorder
How does Lesch Nyan Syndrome present?
Intelectual disability
Aggresive/Impulsive behaviour
Self-mutilation
Gout
Renal Disease
How does Gout present?
Swelling/nodules on joints
Red, hot and painful oints
Most commonly in the toe
The overlying skin may peel
May see white chalkish material under the skin/breaking through
Who gets gout?
Older men mostly.
Women increase in incidence a lot as they age
Why do older women get so much more gout than younger women?
Oestrogen is Uricosuric (i.e. helps excretion) so post-menopausal women get lots of gout
What are the risk factors for gout?
- Hypertension
- Alcohol
- Obesity
- High Cholesterol
- Smoking
- Diabetes
- Shellfish (purine rich)
How do we test someone to confirm gout?
Needle aspiration of the swollen joint:
- Cultures to rule out septic arthritis
- Polarising Microcospy to see the crystals & so confirm gout
What test is useful for managing chronic disease?
Uric Acid blood test
Not useful acutely but good for monitoring chronic levels and effectiveness of treatment
How can we manage an acute flare up of gout?
NSAIDs (Colchicine if NSAIDs not tolerated)
Steroids (Oral/IM/IA)
How do we manage long-term Hyperuricaemia?
1st line - Xanthine Oxidase Inhibitor (Allopurinol)
2nd line - Uricosuric agents e.g. sulphinpyrazone or probenecid
