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
What should you do when starting or increasing allopurinol?
Give prophylactic NSAIDs or Colchicine/Steroids.
As allopurinol can actually trigger gout
When would we treat hyperuricaemia?
Only if:
- Tophaeceous (i.e. large crystals)
- Polyarticular
- Urate Calculi
- Renal Insufficiency
- 2nd attack in 1 yr
Never treat if asymptomatic
What crystals are deposited in pseudogout?
Calcium Pyrophosphate Dihydrate (CPPD)
Who gets Pseudogout?
Elderly women, mostly in the knee
What causes Pseudogout?
Triggered by trauma e.g. a fall or an interurrent illness
How does pseudogout present?
Acutely swollen joint usually after a fall
How do we test for pseudogout?
X-ray can be useful to see chondrocalcinosis in the joint
Needle aspiration to see CPPD crystals confirms q
how to treat pseudogout?
NSAIDs
IA steroids
What is Polymyalgia Rheumatica?
Condition involving stiffness and inflammation in the shoulder and pelvis
Often associated with GCA
How does PR present?
Sudden onset shoulder +/- pelvic girdle stiffness High ESR Anaemia Malaise & WEight loss Fever Depression ~Arthralgia
Who gets PR?
2F:1M
Usually >70yrs
How do we diagnose PR?
Patient:
>50yrs
>50 ESR
REsponds DRAMATICALLY to Steroids
DDX for PR?
Malignancy (Multiple myeloma or lung cancer) Hypo/hyperthyroidism Inflammatory muscle disease Bilateral Shoulder Capsulitis Fibromyalgia
How do we treat PR?
CCS for 18-24 months Bone prophylaxis (Ca, Vit D & Bisphosphonates)
