6.6. Rheumatology - Crystal Arthropathies Flashcards
What characterises Crystal Arthropathies?
Deposition of Mineralised Material within the Joints and Peri-Articular Tissue
What are common Crystal Arthropathies?
- Gout
- Pseudogout
- Calcified Periarthritis / Tendonitis
What crystal deposition is associated with Gout?
Monosodium Urate
What crystal deposition is associated with Pseudigout?
Calcium Pyrophosphate Dihydrate
What crystal deposition is associated with Calcified Periarthritis / Tendonitis?
Basic Calcium Phosphate Hydroxy-apatite (BCP)
What is a Tophus?
A Massive accumulation of Uric Acid
What contributes to the bodies Urate pool?
- 2/3 - Endogenous production of Uric Acid from degradation or Purines
- 1/3 - Dietary
What happens to the Uric Acid (produced Daily)?
- 70% - Excreted via the Kidney
2. 30% - Eliminated into the Biliary Tract, and converted into Allantoin (by Bacteria Uricase)
What are the 2 methods by which Hyperuricaemia can occur?
- Overproduction
2. Under-Secretion
By what methods does Overproduction cause Hyperuricaemia?
- Malignancy
- Severe Exfoliative Psoriasis
- Drugs
- Inborn Errors of Metabolism
- HGPRT Deficiency (Lesch-Nyan Syndrome)
What types of Malignancy can cause Hyperuricaemia, via Overproduction?
- Lymphoproliferative
2. Tumor Lysis Syndrome
What types of Drugs can cause Hyperuricaemia, via Overproduction?
- Ethanol
2. Cytotoxic Drugs
By what methods does Under-Secretion cause Hyperuricaemia?
- Renal Impairment
- Hypertension
- Hypothyroidism
- Drugs
- Exercise, Starvation, Dehydration
- Lead Poisoning
Why does Hyperuricaemia result in the vast majority of people with Gout?
Reduced Efficiency of Renal Urate Clearance
What types of Drugs can cause Hyperuricaemia, via Under-Secretion?
- Alcohol
- Low-Dose Aspirin
- Diuretics
- Cyclosporin