day 2 - pathology of bones and joints Flashcards Preview

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Flashcards in day 2 - pathology of bones and joints Deck (18):
1

osteoporosis incidence

Higher in Caucasian and Asian!
One of the most common conditions of the elderly!
Affects more than 75mil. people
Estimate to cause 8.9 million fractures/year
(EUA, EU, Japan- WHO) !
worldwide
(WHO)

2

osteoporosis overview

generalised
localised / regional

Primary

Secundary:
osteogenesis imperfecta , Turner syndrome, rheumatoid arthritis, glucocorticosteroid use, systemic mastocytosis, hyperthyroidism, adrenal disease, malignancy, steroid or anticoagulant therapy, chronic alcoholism, multiple myeloma, and immobilisation!

3

def osteoporosis

Women with bone mineral density values of more that 2.5 standard deviation (SD) below
that of normal adult mean value ! are at risk of fracture = Osteoporosis!

4

def osteopenia

Women with bone density values of more that 1 SD below that of normal adult mean value = osteopenia!

5

most likely sites of fractures in osteoporosis

hip = neck of femur!
Wrist (Colles’)
Vertebral!

6

explain RANKL pathway

Receptor activator of nuclear factor kappa-B

RANK (receptor) is expressed on the surface of osteoclast precursors and mature osteoclasts.

RANKL, produced by osteoblasts (and other cells) interaction with its receptor, RANK, promotes osteoclast differentiation, increased bone resorption by mature osteoclasts and extension of osteoclast survival via suppression of apoptosis.

Osteoprotegerin (OPG) is a glycoprotein, secreted by osteoblasts and bone marrow stromal cells, is a natural inhibitor of RANKL. OPG blocks the interaction of RANKL with RANK by acting as a ‘decoy receptor’.

Oestrogene limits the amount of RANK ligant expression by ostoblasts.

7

effect of menopause on bone loss

Rapid bone loss at menopausal period – 3% / year in the spine for 5 years

0.5% per annum subsequently

Women may lose up to 40% of bone mass

Presentation of disease 20 years after the menopause

8

If bone loss occurs in all women after the menopause, why does everyone not get osteoporosis?

Peak bone mass – 20 – 30 years of age

More bone available to lose before reaching fracture threshold
Genetic / familial
Race
Gender

9

risk factors for lower bone density

Life style / exercise! Smoking! Alcohol!
!
Diet – low calcium!
Endocrine diseases – ! hyper and hypothyroidism!
Addison disease - Adrenal
Rheumatoid arthritis!
Drugs!
Steroids!
Anticonvulsants

10

prevention of bone loss drugs

anti-resorptive agents
!
Oestrogens
cancer risk – breast and endometrium
value of lower levels ?
!
Bisphosphonates
!
RANKL inhibitors (denosumab)
!


11

types of joint disease

DEGENERATIVE
Osteoarthritis / degenerative joint disease

INFLAMMATORY / AUTOIMMUNE
rheumatoid arthritis
spondiloar thropathies

METABOLIC
Gout

• TRAUMA
• INFECTION
• NEOPLASM

MAY REPRESENT ONE MANIFESTATION OF A MULTI-SYSTEMIC DISORDER

12

what is osteoarthritis

Degenerative changes in the articular cartilage (biochemical / metabolic).

Reactive change in the subchondral bone and the synovium.

Males and females are equally affected with exponential increase in prevalence after age 50.

Monoarticular / polyarticular Weight-bearing joints: knee, hip, spinal joint

Non weight-beating joints: hands and feet (more frequent in women)

Joint pain, stiffness and function impairment Loss of quality of life

13

OSTEOARTHRITIS / DEGENERATIVE JOINT DISEASE causes

Primary (90%): unknown cause
Changes in proteogycan and collage II lead to altered load-bearing properties.

Secondary (10%): as a consequence of pre-existing joint disease that predisposes to the joint failure.
(ex. deformity, RA, metabolic disorder, crystal deposition disease)

14

structure of articular cartilage

Lamina splendens: -superficial flat chondrocytes
!
Middle layer:-round chondrocytes
!
Calcified cartilage: -chondrocytes organised in clusters

Lamina ondulans
!
Subchondra compact bone

15

cartilage structure in osteoarthritis

Roughened cartilage with erosion, depression & linear grooves
!
Whitish areas of fibrous and cartilage repair !
Loss of cartilage with exposure of bone that becomes marble-like (EBURNATION)

16

what are osteophytes in osteoarthritis

Osteophytes - new bone formation at edge of joint !
cause is not understood !
can compress nerves and inflict pain

17

what might you see on an X-ray of an osteoarthritic joint

Narrowing of articular space
!
!
Peripheral osteophyte

18

what happens in rheumatoid arthritis

Systemic autoimmune disease that manifests as a synovial arthropathy
!
Inflammatory arthritis starting as a non-suppurative proliferative synovitis; changes spread to articular cartilage, subchondral bone and peri-articular tissue
!
Cartilage destruction, bone erosion and joint ankylosis.

hand deformities

Immunologically mediated generalised disease which nearly always affects the joints

Familial predisposition (HLA-DR4 and HLA-DR1)
3F:1M

Progressive symmetrical peripheral polyarthritis Chronic inflammation and bone destruction

Small joints of hands and feet followed by elbow, ankle and knee joints
!
PAIN, SWELLING, LIMITED MOBILITY

Erosive joint disease in RA
An overgrowth of fibroblastic and inflammatory cells (pannus) over the cartilage = cartilage is destroyed