Calcium Pyrophosphate Deposition Disease (CPDD)

Question 1

What is CPDD

Answer 1

Acute inflammatory AND mechanical monoarthopathy of the larger joints (normally) characterised by the deposition of pyrophosphate crystals in the joint

Question 2

Epidemiology

Answer 2

Females >50

Question 3

Aetiology

Answer 3

Mostly idiopathic! We don’t know xo xo

Secondary to joint trauma, familiar chonedrocalcinosis, hyperPTH, haemochromatosis, gout

Joint trauma/surgery

Question 4

Pathophysiology

Answer 4

Deposition of CPP crystals in articular cartilage, synovium and periarticular structures
Crystals cause inflammation –> CK and proteases released which damages the cartilage
Crystals also cause mechanical (non-inflammatory) damage

Question 5

History

Answer 5

Rapid onset severe pain
Joint stiffness and tenderness
Asymmetrical mono arthritis –> knee
Malaise and fever

Question 6

Examination

Answer 6

Tenderness to palpation
Erythema, swelling, heat

Question 7

Investigations

Answer 7

Biochemical:
Serum calcium: elevated or normal
PTH to exclude hyperparathyroid
Iron studies to exclude haemochromatosis

Arthrocentesis:
Polarised light microscopy:
+ birefringent rhomboid shaped crystals
WCC >2000

X-Ray:
Can see calficiation/radio-opaque structures but ti isn’t diagnostic

Question 8

DDx

Answer 8

Gout
Septic arthritis

Question 9

Mx actue attack

Answer 9

Cool packs + rest
Aspiration
NSAIDs or colchicine
+/- intra-articular steroids

Question 10

Mx chronic attack

Answer 10

Asymptomatic don’t need treatment
Treat underlying cause
Sometimes they give DMARD

Question 11

Complications

Answer 11

Can get rapidly progressive OA