Podcast
Questions and Answers
How are a-Sodium urate and Calcium pyrophosphate crystals differentiated?
How are a-Sodium urate and Calcium pyrophosphate crystals differentiated?
- By their smell when dissolved in a solvent
- By their size under normal light
- By their density under ultraviolet light
- By their color under polarized light (correct)
What is the classic clinical presentation of gout?
What is the classic clinical presentation of gout?
- Severe pain in the 1st MTP joint at night (correct)
- Acute abdominal pain after a heavy meal
- Intermittent back pain aggravated by bending forward
- Sudden chest pain after exercise
- Gradual onset of neck stiffness
In the mechanism of crystal-induced arthritis, what leads to complement activation?
In the mechanism of crystal-induced arthritis, what leads to complement activation?
- Monocytes engulfing the crystals
- Platelets secreting inflammatory cytokines
- Lymphocytes attacking the joint tissue
- Neutrophils releasing proinflammatory enzymes (correct)
Which factor does NOT affect serum uric acid level according to the text?
Which factor does NOT affect serum uric acid level according to the text?
What characterizes hyperuricemia in terms of serum uric acid levels?
What characterizes hyperuricemia in terms of serum uric acid levels?
What is the primary enzyme inhibited by allopurinol in the management of gout?
What is the primary enzyme inhibited by allopurinol in the management of gout?
Which of the following is NOT a characteristic of gout associated with hyperuricemia?
Which of the following is NOT a characteristic of gout associated with hyperuricemia?
Which condition is NOT associated with an increased risk of developing gout according to the text?
Which condition is NOT associated with an increased risk of developing gout according to the text?
Which condition can result from both impaired excretion and increased production of uric acid?
Which condition can result from both impaired excretion and increased production of uric acid?
What is the recommended initial management for an acute gout attack?
What is the recommended initial management for an acute gout attack?
Study Notes
Crystal Arthritis
- Two main types of crystal arthritis: sodium urate and calcium pyrophosphate
- Crystals are differentiated under polarized light with a red filter by their shapes and perfringence properties
- Crystals induce arthritis by:
- Being ingested by neutrophils, which release proinflammatory enzymes from their phagosomes into the joint
- Activating complement, attracting more neutrophils
Hyperuricaemia
- Defined as serum uric acid level greater than two standard deviations from the mean
- Mean value:
- Male: 7 mg/dl
- Female: 6 mg/dl
- Children: 3-4 mg/dl
- More common in males (10:1 ratio)
Gout and Hyperuricaemia
- Disease of kings, characterized by:
- Elevated serum uric acid level
- Recurrent attacks of arthritis
- Tophi (aggregated sodium urate crystals around joints)
- Renal disease (glomerular or tubular and interstitial)
- Urolithiasis
Causes of Hyperuricaemia
- Impaired excretion or increased production
- Decreased excretion:
- Diseases (chronic renal diseases, hypertension, myxedema, primary parathyroidism)
- Lead toxicity
- Certain drugs (thiazide, low-dose aspirin)
- Increased lactic acid production (alcohol, exercise, and starvation)
- Increased production:
- Congenital disorders (Lesch-Nyhan syndrome, G6PD deficiency)
- Myeloproliferative disorders (polycythemia)
- Lymphoproliferative disorders (leukemia)
- Carcinoma
- Psoriasis
Clinical Presentation of Gout
- Four clinical pictures:
- Asymptomatic hyperuricaemia
- Acute gouty arthritis
- Interval gout
- Chronic tophaceous gout
Factors Affecting Serum Uric Acid Level
- Age
- Sex (rare before menopause)
- Family history
- Certain diseases (diabetes, ischemic heart disease, hypertension, obesity, and type IV hyperlipidemia)
- Diet (rich in proteins) and alcohol consumption
Suspecting and Diagnosing Gout
- Clinical picture
- Elevated serum uric acid level
- Sure test: joint aspirate and polarized microscopy examination
Classic Gout Attack
- Middle-aged male awakes at night with acute severe pain in the 1st MTP joint after heavy meal and alcohol intake or using diuretics
Management of Gout
- Acute episode:
- Non-steroidal anti-inflammatory drugs in high dose for 48 hours, then reduced dose for one week
- Alternative: colchicine or steroids
- Drugs lowering serum uric acid:
- Allopurinol (300-600 mg, then maintenance dose of 100-300 mg)
- Inhibits xanthine oxidase enzyme
- Uricosuric drugs: increase urate excretion, may precipitate urate stone formation
- Diet: stop purine-rich diet, red meat, high-calorie diet, cholesterol-rich diet, alcohol, and spinach
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Description
Learn about the two main types of crystal-induced arthritis - Sodium urate and Calcium pyrophosphate, and how they are differentiated under polarized light. Explore how these crystals induce arthritis through the mechanism involving neutrophils, proinflammatory enzymes, complement activation, and more. Also, understand the definition of hyperuricaemia in relation to serum uric acid levels.
