revision lecture

Question 1

what are the key features of rheumatoid arthritis *

Answer 1

morning stiffness around teh joints

symetrical polyarthritis - typically involving the small joints of the hand/wrist

subcut nodules

rheumatoid factor

joint erosions on radiograph

Question 2

define rheumatoid factor *

Answer 2

Ab that racognise the Fc portion of IgG as their target Ag

IgM targetting IgG

IgM is pentameric so get big complex

Question 3

what is hyaluronic acid

Answer 3

a non-sulfated glycosaminoglycan

Question 4

collagen type in synovium *

Answer 4

1

Question 5

define reactive arthritis *

Answer 5

sterile inflamm synovitis following an infection

extra-articular manifestations - enthesopathy, skin inflammation (cricinate balanitis, keratoderma blennorrhagicum - this is psoarisis like skin lesions )

eye inflammation (conjunctivitis)

control the symptoms but patients get better over time

important to know the different features because if have all dont need to giev AB for eye - giev anti-inflamm and should get better

however - could be 1st manifestation of psoriatic arthritis, could be presentation fo ankylosing spondylitis

Question 6

infections associated with reactive arthritis *

Answer 6

Urogenital infections

enterogenic infections

may be the 1st manifestation of HIV or Hep C infection

need to think about these for treatment

Question 7

describe and give 2 examples of enthesopathy *

Answer 7

inflammation where a ligament, tendon, fascia or capsule insert into the bone

they are seronegative arthropathies

eg

achilles tendon - painful heel - inflamm where inserts into calcaneum - may be trauma or inflammatory arthropathy

plantar fascilitis - painful feet - inflammation at insertion of plantar fascia

dactylitis - swollen digits - inflammation at insertion of capsule and ligamnets in digits

Question 8

compare these featres of rheumatoid and reactive arth *

Answer 8

Question 9

summarise the pathological finding inosteoarthritis *

Answer 9

irreversible loss of articular cartilage

there are focal areas of damge to articular cartilage

new bone formation at joint margins - osteophytosis

changes in subchondral bone - sclerosis

Question 10

define proteoglycan *

Answer 10

glycoproteins containing sulfated glycosaminoglycan chains - eg aggrecan

Question 11

define glycosaminoglycan *

Answer 11

repeating polymers of disaccharides eg

chondroitin sulphate

keratin sulphate

hyaluronic acid

Question 12

what is the major collagen and proteoglycan found in articualr cartilage *

Answer 12

type 2 collagen

aggrecan

Question 13

describe the structure and composition of articular cartilage *(

Answer 13

type 2 collagen

aggrecan - monomers are arranged into supramolecular aggregates consisting of central hyaluronic acid filament and non-covalently linked aggrecan

negatively charged chemical groups of GAGs attract water into cartilage - 80% of the net weight is water

Question 14

compare the radiographic signs of rheumatoid arthritis and osteoarthritis *

Answer 14

joint space narrowing not present early in Rheum

get osteopenia around the immobile joint

Question 15

list the major HLA association for

ankyloising spondylitis and reactive arthritis

SLE

rheumatoid arthritis *

Answer 15

ank and reactive - HLA-B27

SLE HLA-DR3

rheum HLA-DR4

Question 16

summarise the composition of bone *

Answer 16

comprised of protein matrix (osteoid) and mineral hydroxyapatite

osteoclasts resorb bone and osteoblasts form it

Question 17

define osteoporosis *

Answer 17

predisposition to skeletal fractures resulting from a reduction in regional or total bone mass

bone chemistry is normal - serum ca, phos, pth and alkaline phosphtase

assesed by DEXA - defined by a T score

T score is comparison of pts mean bone mass to the mean of young normal subjects - mean of young normal subjects represents ‘peak bone mass’

T score calculates how many SDs pts score is above or below the peak bone mass

get osteopenia and fragility fractures

Question 18

define osteomalacia *

Answer 18

impaired mineralisation in mature bones, rickets is impaired mineralisation in immature bones

most frequently due to inadequate extracellular fluid conc of phosphate or ca

Question 19

causes of osteomalacia *

Answer 19

vit D def

abnormal vit D metabolism - eg liver or kidney disease

hypophosphtaemia - may be due to renal phosphate loss which can be determined by measureing urinary phosphate levels

Question 20

what are the biochemical changes in bone diseases *

Answer 20

Question 21

what is osteomalacia associated with *

Answer 21

low or normal serum ca

low phos - PTH drives phosphate out of the kidney

secondary hyperparathyroidism - high pth and serum alkaline phosphtase

osteopenia and pseudofractures eg looser ones

in rickets - flared ends of bones and bowing of long bones

Question 22

define pagets *

Answer 22

disroder of bone remodelling of unknown cause where there is increased bone resorption followed by increased formation = disorganised mosaic of woven and lamella bone

bone chemistry shows high alkaline phosphtase

increased cortical bone thicjness on radiographs eg sclerosis

abnormal bone causes pain and bone deformity and sometimes fractures

expansion of bone

Question 23

rare causes of OA *

Answer 23

metabolic and genetic

Question 24

describe the joint in OA *

Answer 24

have exposed bone

joint space narrowing becaus eof lack of articular cartilage

Question 25

why is it important to understand aggrecan in synovial joints *

Answer 25

targeting their breakdown could be useful for future therapies