Flashcards in 6.6. Rheumatology - Crystal Arthropathies Deck (36):
What characterises Crystal Arthropathies?
Deposition of Mineralised Material within the Joints and Peri-Articular Tissue
What are common Crystal Arthropathies?
3. Calcified Periarthritis / Tendonitis
What crystal deposition is associated with Gout?
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?
1. 2/3 - Endogenous production of Uric Acid from degradation or Purines
2. 1/3 - Dietary
What happens to the Uric Acid (produced Daily)?
1. 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?
By what methods does Overproduction cause Hyperuricaemia?
2. Severe Exfoliative Psoriasis
4. Inborn Errors of Metabolism
5. HGPRT Deficiency (Lesch-Nyan Syndrome)
What types of Malignancy can cause Hyperuricaemia, via Overproduction?
2. Tumor Lysis Syndrome
What types of Drugs can cause Hyperuricaemia, via Overproduction?
2. Cytotoxic Drugs
By what methods does Under-Secretion cause Hyperuricaemia?
1. Renal Impairment
5. Exercise, Starvation, Dehydration
6. 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?
2. Low-Dose Aspirin
What deficiency is assoiciated with Lesch-Nyan Syndrome?
Deficiency of the enzyme Hypoxanthine-Guanine Phosphoribosyl Transferase (HGPRT)
How is HGPRT Deficiency transferred in Lesch-Nyan Syndrome?
What is the function of HGPRT?
Note - related to Lesch-Nyan Syndrome
This plays a key role in the recycling of the Purine Bases (Hypoxanthine and Guanine)
What happens in the Absence of HGPRT?
Note - relates to Lesch-Nyan Syndrome
1. The Purine Bases cannot be salvaged, so are degraded / excreted as uric acid
2. Synthetic rate of Purines is accellerated - causing the overproduction of Uric Acid
How does Lesch-Nyan Syndrome present?
1. Intellectual Disability
2. Aggressive and Impulsive Behaviour
5. Renal Disease
Who commonly gets Gout?
Note - males have higher Urate Levels and increased prevalence at all ages
How is Gout Diagnosed?
3. Appropriate Invetsigation
How is an Acute Flare up of Gout managed?
3. Steroids (I/A, I/M, Oral)
When is the Hyperuricaemia of Gout managed?
1. Single attack of Polyarticular Gout
2. Tophaceous Gout
3. Urate Calculi
4. Renal Insufficiency
5. 2 x attacks in 1 year
6. Prophylactically prior to treating certain malignancies
Note - this is not treated if asymptomatic
What medications are used to treat the Hyperuricaemia associated with Gout?
1. Xanthine Oxidase Inhibitor (Allopurinol)
3. Uricosuric Agents (Sulphinpyrazone)
What are the rules of Lowering Uric Acid Levels?
1. Wait until the acute attack has settles
2. Use Prophylactic NSAID's / Low dose Colchicine/Steroids until Urate Levels are normal
3. Adjust Allopurinol dose according to Renal Function
What is the main treatment for Gout?
Adjusting Cardiovascular and Lifestyle Factors
Who commonly presents with Pseudogout?
What is the Aetiology of Pseudogout?
How does Pseudogout present?
1. Erratic flares, triggered by:
1. a) Trauma
1. b) Intercurrent Illness
2. Chondrocalcinosis (on X-Ray)
3. Pyrophosphate Crystals (on Biopsy)
What is the management of Pseudogout?
2. I/A Steroids
Note - there are no prophylactic therapies
What is Polymyalgia Rheumatica associated with?
Giant Cell Arteritis:
1. 20% of patients with PMR may have evidence of GCA
2. 50% of patients with GCA may have PMR
Who is commonly affected by Polymyalgia Rheumatica?
1. Elderly (>50)
2. Females (2:1)
How does Polymyalgia Rheumatica present?
1. Sudden onset of Shoulder / Pelvic Girdle Stiffness
2. High ESR (>50)
4. Malaise / Weight Loss / Fever / Depression
5. Arthalgia / Synovitis (occasionaly)
What is the Differential Diagnosis for Polymyalgia Rheumatica?
1. Myalgic Onset Inflammatory Joint Disease
2. Underlying Malignancy (Multiple Myeloma, Lung Cancer)
3. Inflammatory Muscle Disease
5. Bilateral Shoulder Capsulitis