Crystal Associated Arthritis

Question 1

CA Pathogenesis

Answer 1

Crystals form in tissues when their constituents exceed their solubility threshold
(Usually avoided by the presence of inhibitors)

Favourable factors:

• decreased temperature
• decreased pH
• crystal nucleators

Crystals are disturbed-> trauma, illness, surgery, partial treatment-> shed in to synovial fluid/bursa-> inflammation

Question 2

Calcium pyrophosphat dehydrate crystals CPD epidemiology

Answer 2

Deposited at enthesis and hyaline cartilage
-> chondrocalcinosis 
Most commonly knees
30% >70y
Females

Question 3

CPD risk factors

Answer 3

Commonly idiopathic 
Age
OA
Metabolic
-haemachromatosis
-Wilsons
-hypothyroid
-hypoparathyroid 
Dehydration
Infection
Acromegaly 
Gout

Question 4

CPD clinical features

Answer 4

Incidental findings on X Ray
Pseudo-gout
-severe pain
-swelling
-tenderness
-erythema
-fever

Chronic:

• gradual onset
• pain
• stiffness
• decreased ROM
• OA and synovitis

Question 5

CPD investigations

Answer 5

Joint aspiration-> polarising light microscopy
X Ray
-chondrocalcinosis
-OA

Question 6

CPD management

Answer 6

Analgesia
Aspiration and corticosteroid injection
No prophylaxis

Question 7

Basic calcium phosphate BCD clinical features

Answer 7

Commonly a symptomatic 3-4% of pop 
Soft tissues
Pain
Erythema
Swelling
Fever

Supraspinatus tendon
Middle age
Spontaneous trauma

Question 8

BCD investigations

Answer 8

Aspiration
X-ray
-tendon associate calcinosis

Question 9

BCD management

Answer 9

Analgesia

Aspiration and steroid

Question 10

Gout epidemiology

Answer 10

Mono sodium irate mononuclate
1-4%
Men
7% of >75y
Most common inflammatory arthritis 
40-50y
Rare before menopause

Question 11

Gout risk factors

Answer 11

>0.36
Age
Male
Obesity 
Renal insufficiency 
Diuretics
Hypertension
Hyperglycaemia 
Metabolic syndrome

Question 12

Gout aetiology

Answer 12

Uris acid is the end product of purine metabolism
2/3 renal you excreted
Hyperuriciemia + genetic renal defect

Question 13

Acute gout clinical features

Answer 13

Rapid onset mono arthritis 
Developed over night
MTPJ joint 50% 
Sever pain
Shiney, warm, erythematous skin
Fever
Resolves spontaneously in 1-2w

Question 14

Chronic gout clinical features

Answer 14

Uncontrolled hyperuricaemia
Recurrent attacks
Asymetrical poly arthritis 
Tophi
-helix
-bursa
-tendon sheaths
-peri articular 
10% renal colic

Question 15

Gout investigations

Answer 15

Joint aspiration and polarising light -> strong negative bifringence 
Raised CRP and ESR 
X-ray 
-calcified soft tissue swellings
-punched out erosions with sclerotic regions
-cartilages erosion 
USS
-crystal depositions
BP and renal function 
Asses CV risk

Question 16

Acute gout management

Answer 16

Rest
Analgesia
Joint aspiration and injection
Avoid aspirin

Question 17

Chronic gout management

Answer 17

Reduce SUA to bellow 0.3
Don't start till acute episode subsides
1) Avoid/discontinue diuretics
Gradual wt loss
Increased fluid intake
Decrease alcohol and fructose

2) allopurinol -> inhibitor
100mg and NSAIDS
Measure monthly

3) febuxostat-> inhibitor
Sulfinpyrazone

Avoid shellfish and red meat