Pathology of Joints

Question 1

Why is use and movement essential for joint health?

Answer 1

because the movement squeezes the water out of cartilage and allows synovial fluid to come in and supply nutrients to the joint

Question 2

Is synovium an epithelium?

Answer 2

no - it doesn’t have basement membrane or junctional complexes

Question 3

What are the different types of synoviocites?

Answer 3

type A which is macrophage like and type B which is fibroblast like (to produce the hyaluronic acid)

Question 4

What is the pathogenesis of osteoarthritis?

Answer 4

begins with damage of the cartilage which activates chondrocytes, the chondrocytes proliferate and release enzymes (collagenases and MMPs) and cytokines which initiates inflammatory processes and depletes the matrix and results in further damage of the cartilage - constant wear and tear and damage results in the chondrocytes dying - when there is no longer enough cartilage in the joint this results in damage to the bone

Question 5

What bone changes are seen in osteoarthritis?

Answer 5

eburnation of bone (thickened, white and shiny bone), subchondral cysts (synovial fluid going into the bone), micro fractures, osteophytes

Question 6

What is the morphology of the cartilage in osteoarthritis?

Answer 6

fibrillation - shredded cartilage

Question 7

What are the signs and symptoms of osteoarthritis?

Answer 7

reuced RoM, crepitus, osteophytes, insidious onset, deep achey pain that is worse after activity

Question 8

How do you diagnose osteoarthritis?

Answer 8

x-ray - subchondral sclerosis, subchondral cysts, loss of joint space, osteophytes

Question 9

What are the risk factors for osteoarthritis?

Answer 9

age, obesity, previous injury, repetitive high use of joint, genetic

Question 10

What is the pathogenesis of rheumatoid arthritis?

Answer 10

autoimmune attack of joints - activates T helper cells, induces fibroblasts, macrophages, neutrophils, plasma cells, dendritic cells, osteoclasts and B cells - the end result of the inflammatory process is a breakdown of cartilage and bone

Question 11

What cytokines are involved in rheumatoid arthritis?

Answer 11

IL-1, IL-6, IL-17, TNF-alpha

Question 12

How does rheumatoid arthritis affect the skin?

Answer 12

subcutaneous nodules

Question 13

What is pannus?

Answer 13

granulation tissue that lines the joint in rheumatoid arthritis and invades into and erodes the bone

Question 14

What happens to bone in rheumatoid arthritis?

Answer 14

bony unions

Question 15

What does the synovium of rheumatoid arthritis look like histologically?

Answer 15

villous hyperplasia, mononuclear infiltrate, germinal centres

Question 16

What are the signs and symptoms of rheumatoid arthritis?

Answer 16

warm swollen joints, rheumatoid nodules, systemic symptoms (fever, weight loss, anaemia), morning stiffness that eases with activity - usually effects joints in hands and feet first

Question 17

Which joint is usually spared in rheumatoid arthritis?

Answer 17

DIP

Question 18

What are the features of a rheumatoid nodule?

Answer 18

granulomatous inflammation - epithelioid macrophages, central necrosis, lymphocytes and fibrosis

Question 19

How do you diagnose rheumatoid arthritis?

Answer 19

general inflammatory tests (CRP, ESR, FBE) and specific tests (RF and anti-CCP)

Question 20

What are the x-ray findings of rheumatoid arthritis?

Answer 20

juxta-articular osteopenia, subchondral erosions, uniform joint space loss

Question 21

What are the risk factors of rheumatoid arthritis?

Answer 21

genetic, female, age (25-55), smoking

Question 22

What is the pathogenesis of gout?

Answer 22

acute inflammatory response to urate crystals in the joint - inflammasome activation which triggers an inflammatory cascade

Question 23

Why does urate crystals precipitate in the joints?

Answer 23

because of the chemical composition of the synovial fluid, the lower temperature, low pH

Question 24

What do you see histologically in gout?

Answer 24

urate crystals, immune cells, and granulomatous inflammation if its chronic gout (epithelioid macrophages, multinucleate giant cells)

Question 25

What are the signs and symptoms of gout?

Answer 25

acute inflamed joint, tophi if chronic, severe pain, swelling, heat and redness

Question 26

How do you diagnose gout?

Answer 26

aspiration of the joint

Question 27

What are the risk factors for gout?

Answer 27

men, diet rich in purines, alcohol, genetics, ethnicity, obesity, hypertension, diabetes,