Crystal arthropathies

Question 1

Name 2 crystal arthropathies

Answer 1

Gout

Pseudogout

Question 2

Gout - definition

Answer 2

Inflammatory arthritis with needle shaped monosodium urate crystal deposition within a joint

Question 3

Gout - epidemiology

M/F, age

Answer 3

More common in males

Prevalence increases with age

Question 4

Gout - risk factors

Answer 4

Dehydration
Trauma
Surgery
Excess alcohol 
Thiazide diuretics 
Red meat

Question 5

Gout - commonly affected areas

Answer 5

Big toe
Knee
Ankle

Question 6

Gout - pathogenesis

Answer 6

Occurs due to excessive amounts of uric acid within tissues and body fluids
Increased uric acid levels due to:
- overproduction of uric acid OR
- reduced excretion of uric acid
This leads to formation of needle shaped monosodium rate crystals which activate the complement system and lead to the production of pro-inflammatory mediators

Question 7

Gout - what is uric acid?

Answer 7

End product of purine metabolism

Question 8

Gout - clinical features (acute)

Answer 8

Rapid onset 
Red, hot joint 
Severe pain 
Lasts 7-10 days then symptoms resolve 
May mimic septic arthritis

Question 9

Gout - clinical features (chronic)

Answer 9

Chronic joint inflammation after having multiple acute attacks
Tophi - large inflamed area, painless

Question 10

Gout - investigations

Answer 10

Bloods
- raised inflammatory markers 
- Increased WCC 
- measure serum urate 2 weeks following acute attack 
X-ray
- normal in initial acute attack 
- repeated attacks: erosions, osteophytes, joint destruction
Joint aspirate 
- To ensure it is not septic arthritis 
- analyse a sample of synovial fluid 
- crystals are needle shaped 
- negative birefringence

Question 11

Gout - management (acute)

Answer 11

NSAIDs
- (use colchecine for people who can’t tolerate NSAIDs)
Steroids
Opioid analgesics

Question 12

Gout - management (recurrent attacks)

Answer 12

Allopurinol

• urate lowering therapy
• don’t start until attack has settled as they may initiate another flare
• no need to stop for acute flare if already taking it
• inhibits xanthines to reduce levels of uric acid

Question 13

Pseudogout - definition

Answer 13

Inflammatory arthritis associated with rhomboid shaped calcium pyrophosphate deposition within a joint

Question 14

Pseudogout - epidemiology

Age

Answer 14

Elderly

Question 15

Pseudogout - commonly affected areas

Answer 15

Affects fibrocartilage so common in …
Knees
Ankles
Wrists

Question 16

Pseudogout - pathogenesis

Answer 16

Calcium pyrophosphate deposition occurs in cartilage and other soft tissues in the absence of acute inflammation

Question 17

Pseudogout - investigations

Answer 17

Joint aspirate
- rhomboid shaped crystals 
- weakly positive birefringence result 
X-ray
- chondrocalcinosis

Question 18

Pseudogout - management

Answer 18

NSAIDs
(use colchicene if unable to take NSAIDs)
Steroids