Calcium Pyrophosphate Deposition Disease

Question 1

CPP in short

Answer 1

Deposition of CPP crystals into joints

Variety of clinical presentation from chronic polyarticular pain to acute inflammatory mono

Question 2

CPP pathogenesis up to the deposition of crystals

Answer 2

Inorganic pyrophosphate made from ATP

Chondrocyte membrane known as ANKH controls efflu of ATP out of condrocytes and is therefore responsible for concentration of ePPi

High amounts of PPi in synovial space increases formation of crystals

Alkaline phosphatase degrates Pi, making it unavailable for crystallization

Any process that decrease alkaline phosphatase will favor formation

Stress on chondrocytes increases ATP release and therefore favors crystal formation

Question 3

Effect of the crystals…pathologic

Answer 3

Induce infalmmatory reaction and increase release of matrix metalloproteinase from synoviocytes and chorndorcytes

Leads to cartilage degeneration

Also depostis in artticular cartilabe and alters mech processes

Question 4

Other diseases that are associated with CPPD and why

Answer 4

Joint diseases because of chondrocyte stress (osteoarthritis, gout)

Metabolic conditions (hypophosphatasia with low alkaline phosphatase)

Also hyperparathyroidism, hypomagnesaemia, hemochromatosis, hypothyroidism, Wilson’s dz

Question 5

CPPD epidemiology

Answer 5

Maybe 5% over 60…40% over 80

Question 6

Acute CPPD

Answer 6

Pseudogout

Acute mono or oligo artthritis…most in knee, wrist, elbow and or ankle

Tends to be asymmetric with multiple joints in the same limb affectred

Systemic sx may be present

Tend to be precipitated by physuologic stress…resolve slowly

Question 7

Chronic CPPD

Answer 7

POlyarticular involvement with similar joints to osteoarthritis

Chronic CPPD (different than OA), has intermittent flares characterized by an acute inflamm arthritis and progressive joint damage

Chronic also affects the shoulder, wrist, and MCP joints

Rarely presents like rheumatoid arthritis

Question 8

Acute dx

Answer 8

Over 60 with acute mono or oligo pain

Evelated or ESR and CRP

If joint effusion, then arthrocentesis…look for positively birefringent, rhomboid shaped crystals in synovial fluid (pathognomonic)

Question 9

Chronic dx

Answer 9

Over 60 with chornic polyarticlar…esp wrists or MCP joints with bouts of inflamm arthritis

If severe OA and joint degeneration, could also have CPPD dz

Question 10

Radiography CPPD

Answer 10

Visualization of chondrocalcinosis (calcifciation of cartilage)

Common in menisci of the knee, triangular cart of radioulnar wrist, or glenoid labrum

Can also use ultraosund to detect hyperechoic linear densitiies

Question 11

Acute manamgnet

Answer 11

Anti-inflam therapy

Intra-articular GCs…alternatives are NSAAIDs and colchicine

Question 12

Chronic managment

Answer 12

NSAIDs and colchicine may decreasefreq of acute flares