Crystal Arthropathies

Question 1

What are the investigations for crystal arthropathies?

Answer 1

• Aspiration of joint fluid with polarised light microscopy, culture and sensitivity. A raised WCC may be seen but it is < 50,000/mm3

Question 2

What is the crystal appearance in gout?

Answer 2

• Monosodium uric acid crystals which are negatively birefringent needle shaped.

Question 3

What is the crystal appearance in psudogout?

Answer 3

• calcium pyrophosphate crystals which are positively birefringent rhomboid shaped crystals

Question 4

What are the blood tests for crystal arthropathies

Answer 4

• Uric acid (gout only)
• Renal function (gout only) as renal impairment is a risk factor for gout
• Inflammatory markers

Question 5

What are the radiological investigations for crystal arthropathies

Answer 5

• Joint X ray or ultrasound
  Gout - Xray is good for baseline as changes occur after multiple attacks
  Pseudogout - May show condrocalcinosis and changes as seen in osteoarthritis

Question 6

What is the presentation of gout?

Answer 6

Arthritis of the 1st metatarsophalangeal joint. Presents with sudden, severe attacks of pain, swelling, redness and tenderness

Question 7

What are the non-modifiable risk factors for gout?

Answer 7

• Male biological sex
• Age over 50
• Family history of gout,
• Lesch-Nyhan syndrome

Question 8

What are the modifiable risk factors for gout?

Answer 8

• Obesity
• Hypertension
• CKD
• Diabetes
• Metabolic syndrome
• Medications eg, thiazide diuretics, ACE inhibitors and aspirin

Question 9

What are the triggers for gout?

Answer 9

• Foods high in purine (drinks high in fructose, meats, dried beans and seafood)
• Alcohol,
• Protein rich foods,
• Emotional stress,
• Fatigue,
• Illness,
• Chemotherapy,
• Trauma and surgery

Question 10

What are the symptoms for gout?

Answer 10

• Excruciating, sudden, burning pain.
• Swelling, redness, warmth and stiffness,
• Asymmetric joint distribution,
• Mild fever,
• Tachycardia

Question 11

What are the differentials of monoarthropathy?

Answer 11

1. septic arthritis,
2. Crystal arthropathy
3. Inflammatory arthritis

Question 12

What is the management of acute gout attacks?

Answer 12

• NSAIDs (Indomethacin)
• Colchicine (diarhoea can be problematic side effect),
• Steroids (can be intra-articular)
• Paracetamol

Question 13

What are the lifestyle changes for the prevention of gout?

Answer 13

• Reduce alcohol consumption,
• Reduced purine-based foods,
• Review thiazide/loop diuretics, chemo and aspirin

Question 14

What are the indications for allopurinol?

Answer 14

• More than 2/3 attacks per year,
• Tophaceous gout (masses of urate form in joint called tophi,)
• X ray changes,
• Urate nephrolithiasis
• Patient experiences severe, disabling polyarticular attacks
  (only started at least 2 weeks following attack, otherwise it may worsen an acute attack)

Question 15

What are the risk factors for psuedogout?

Answer 15

• Advanced age,
• Injury or previous joint surgery,
• Hyperparathyroidism,
• Haemochromatosis,
• Hypomagnesaemia,
• Hypophosphataemia

Question 16

What is the presentation of pseudogout?

Answer 16

• Inflammation and pain in one joint (may be more) commonly in wrist or shoulder
• Swelling, effusion, warmth and tenderness

Question 17

What is the treatment for pseudogout?

Answer 17

Same as for gout except there is no prophylaxis.
Treatment is usually with a course of NSAIDs (colchicine if NSAIDs are contraindicated, if both are contraindicated then steroids can be used)