Topic 5: Joint Disease Flashcards Preview

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Flashcards in Topic 5: Joint Disease Deck (34):
1

What are some functions of synoviocytes?

-phagocytose dead/dying tissue
-secrete synovial fluid
-maintain homeostasis within joint

2

What are some functions of the synovial membrane?

-produce lubricin and hyaluronic acid (maintains integrity of AC)
-nutrient exchange

3

What are the functions of AC?

-frictionless motion
-even distribution of joint load
-disperse energy from loading

4

What are the properties of AC?

-avascular --> no inflammatory response
-aneural --> no source of pain
-alymphatic
-hypocellular --> low density of chondrocytes

5

What type of inflammation is OA?

dysregulated para-inflammation

6

What is the onset age of OA?

50-60yrs

7

What types of problems occur as a result of OA?

synovitis, alterations of joint capsule, degeneration of menisci and ligaments, AC breakdown, osteophyte formation, subchondral bone oedema + swelling

8

Role of synovium in OA

-decreased levels of HA and lubricin
-decreased cartilage protecting factors and increased degradation factors
-synovial inflammation precedes structural changes

9

Role of AC in OA

-over-expression of degradation enzymes
-fibrillation

10

Role of biomechanical influences in OA

-mal-alignment: abnormal load distribution
-loss of mensical tissue: alterations in load transmission, increased peak load stresses
-cartilage lesions: exposure of sub-chondral bone
-joint instability and ligament laxity: increased translation

11

Role of obesity in OA

adipokines - pro-inflammatory

12

Role of age-related changes in OA

-increased SASP secretion
-oxidative stress/damage
-decreased growth factors
-increased AGE formation (advanced glycation end-product)

13

Inducers of OA

Endogenous
-cell-derived alarmins
-tissue-derived metabolites
-ECM-derived
-AGEs

14

Sensors of OA

PRRs
-osteocytes and chondrocytes in sub-chondral bone
-tissue-resident macrophages
-synoviocytes
-chondrocytes

15

Effectors of OA

-AC chondrocytes
-tissue-resident macrophages and mast cells
-fibroblasts in ligament capsule
-osteocytes and chondrocytes in sub-chondral bone
-synoviocytes

16

Clinical features of OA

-crepitus
-decreased muscle strength
-joint instability
-deformities - genu varus/valgum
-pain in joint
-loss of ROM
-joint enlargement

17

Pathology of OA

-cartilage loss - decreased matrix material produced
-cartilage softening --> cracking, flaking, fibrillation, fissuring --> exposure of subchondral bone --> eburnation
-sunchondral cysts
-local muscle weakness

18

What is the onset age of RA?

25-50 years

19

What is the gender bias of RA?

females 2.5:1

20

What is an antigen?

cause immune response to produce antibodies

21

What is an antibody?

immunoglobulins, specific, adaptive immune system

22

What is an auto-antigen?

endogenous, body attacks self

23

Aetiology of RA

-Rh factors produce (auto-antibodies that react with immunoglobulins)
-immune complexes lodge in walls of synovial joints and blood vessels and attract immune cells

24

Inducers of RA

-endogenous - genetic factors
-PAMPs and DAMPs - cell-derived alarmins (Rh factors), tissue-derived inducers, pathogen-derived alarmins
-exogenous: microbial (PAMPs, virulence factors), non-microbial (allergens, irritants)

25

Sensors of RA

PRRs
-chondrocytes
-synoviocytes
-B + T cells
-osteocytes + condrocytes in sub-chondral bone
-tissue-resident macrophages

26

Effectors in RA

-AC chondrocytes
-tissue-resident macrophages
-synoviocytes
-osteocytes and chondrocytes in sub-chondral bone
-T + B cells
-antigen-antibody complexes

27

What is pannus?

-collection of fibroblasts, T + B lymphocytes
-fills joint space and contributes to fibrillation of AC
-releases cytokines and enzymes

28

What is the onset age of RA?

25-50yrs

29

What are some potential causes of RA?

stress, genetics

30

Does Rh trigger RA?

no, because not everyone with RA has Rh factors

31

Clinical features of RA?

-joint pain + tenderness
-swelling
-flu-like symptoms
-decreased ROM
-joint deformities

32

What are whole body features of RA?

-subcutaneous nodules, vasculitis, pericarditis, nodules in sclera, renal sclerosis, sleep disturbances

33

What is the pattern of joint involvement in RA?

bilateral, polyarticular

34

What is the pattern of joint involvement in OA?

weight-bearing synovial joints usually