Gout and pseudogout

Question 1

Define gout

Answer 1

type of arthiritis caused by monosodium urate crystals

Question 2

risk factors for gout

Answer 2

Uric acid can increase in:
- Alcohol
- Medications – thiazide and loop diuretics, aspirin, ACEi and chemo.
- More uric acid in illnesses (due to higher cell turnover), e.g psoriasis and haemopathologies.
- Obesity - metabolic syn
- HTN
- Kidney damage (as uric acid is mainly excreted by the kidney, some in the stool).
- Diabetes
- Vascular disease
- Lipid disorders.
Others – Male, >50 yrs, FHx of gout.

Question 3

Typical presentation of gout

Answer 3

• Acute attack – sudden, burning pain in affected joint.
  o Pain – cannot touch bedsheets.
• Swelling, redness, erythema, stiffness in affected joint.
• Mild fever.
• Tachycardia in response to acute pain.

May have associated gout tophi = deposits of uric acid in subcutaneous tissue.
- Common in distal interphalangeal joints.

Question 4

Common sites for gout

Answer 4

• Base of the big toe (metatarsophalangeal joint) - PODAGRA
• Wrists
• Base of thumb (carpometacarpal joints)
• Knee
• Ankle

Question 5

How is gout diagnosed?

Answer 5

aspiration of synovial joint which shows:
- needle shaped monosodium urate crytsals
- neg birefringement of polarised light

XRAY which shows:
- lytic lesions
- punched out erosions with sclerotic borders and overhaning edges

Question 6

Mangement of acute gout flare up

Answer 6

• Rest, elevate affected joint, ice (usually resolve sin 10 days without tx).
• 1st line – NSAID (indomethacin)
• 2nd line – colchicine – used if NSAID unsuitable, e.g renal impairment, high risk if GI side effects, heart disease.
• 3rd line – intra articular administration of steroids.

Question 7

What is the prophylaxis treatment for gout and pseudogout:

Answer 7

Gout:
- Allopurinol
- Lifestyle – weight loss, hydration, minimize alcohol and purine rich foods.
- Review meds that cause hyperuricaemia – thiazide and loop diuretics, low dose salicylates, chemo.

No prophylactic Tx for pseudogout.

Question 8

What are the indications of prophylactic Tx with allopurinol for gout?

Answer 8

 More than 2/3 attacks per year
 Tophaceous gout
 X-ray changes showing chronic destructive joint disease
 Urate nephrolithiasis
 Patient experiencing severe and disabling polyarticular attacks

Question 9

What is pesudogout?

Answer 9

Ca2+ pyrophosphate crystals in joints.

Question 10

Risk factors for pseudogout?

Answer 10

• Old age
• Injury/ previous joint surgery
• Hyperparathyroidism
• hypoMg, Phos
• haemochromatosis

Question 11

what is the typical presentation of pseudogout?

Answer 11

• elderly
• painful, swelling, erythema, shiny in affected joint.
• Usually chronic condition – inflammation and pain in one joint (or oligioarticualr) – worsens over wks.
• can by asymp

Question 12

Where does pseudogout typically present?

Answer 12

• knee
• shoulder
• wrist
• hips

Question 13

how is pseudogout diagnosed?

Answer 13

synovial fluid aspiration which shows:
- Calcium pyrophosphate crystals
o Rhomboid shaped crystals
o Positive birefringent of polarised light

XRAY showing:
- Chondrocalcinosis
- LOSS - same as osteoarthiritis

Question 14

What is the difference in fluid aspiration and XRAY results between gout and pseudogout?

Answer 14

synovial fluid aspiration:
gout:
- negative birefringement of polarised light
- needle shaped monosodium urate crystals.

Pseudogout:
- Postive birefringement of polarised light
- Calcium pyrophosphate, Rhomboid shaped crystals

XRAY - in pseudogout shows Chondrocalcinosis (pathognomonic of pseduogout).

Question 15

Management of pseudogout

Answer 15

• Chronic asymp changes on XRAY that are asymp – no Tx
• Symp resolve spont over couple wks. Symp Mx
  o 1st line – NSAID
  o 2nd line – colchicine
  o 3rd line – oral steroids (or intra-articular steroid injection).