pathology

Question 1

what is osteoarthritis

Answer 1

Most common form of joint disease. Results from damage to articular cartilage induced by an interaction of genetic, metabolic and biochemical factor, leading to an inflammatory response affecting cartilage, subchondral bone, ligaments, menisci, synovium and capsules

Question 2

what is the pathogenesis of osteoarthritis

Answer 2

• ageing and biochemical stress
• primary = insidious, no overt cause, age related
• secondary = predisposing condition, excess/inappropriate weight bearing, deformity, injury, systemic conditions

Question 3

what is cartilage made of

Answer 3

water, organic extracellular matrix components, mainly type 2 collagen and aggrecan or other proteoglycans

Question 4

what is the pathogenesis of osteoarthritis

Answer 4

structural changes include surface fibrillation and ulceration with loss of cartilage that exposes underlying bone to stress, producing microfractures and cysts leading to abnormal sclerotic subchondral bone and overgrowths at joint margins, called osteophytes

Question 5

what mechanisms can cause osteoarthritis

Answer 5

• abnormal stress and loading
• obesity
• matrix degradation
• tissue inhibitors metalloproteinases
• osteoprotegerin, RANK and RANK ligand
• aggrecanase
• inflammatory mediator release
• growth factors
• cell derived and/or cartilage breakdown products

Question 6

what are clinical features of oesteoarthritis

Answer 6

Causes mechanical pain with movement and/or loss of function

Early OA is rarely symptomatic unless accompanied by a joint effusion while advanced radiological and pathological OA is not always symptomatic

Question 7

what are symptoms of osteoarthritis

Answer 7

• joint pain with movement and/or weight bearing
• short lived morning joint stiffness
• functional limitations

Question 8

pathogenically what are the features of osteoarthritis

Answer 8

early

• damage to cartilage
• clusters of chondrocytes
• small fissures in cartilage
• fibrillation

late

• cartilage is completely worn away- bone on bone
• subchondral cysts
• surface becomes “polished” - eburnation
• remodelling to cope with stress
• formation of osteocytes

Question 9

what are signs of osteoarthritis

Answer 9

crepitus 
restricted movement 
bony enlargement 
joint effusion and variable levels of inflammation 
bony instability and muscle wasting

Question 10

what characterises inflammatory arthritis

Answer 10

synovial inflammation

Question 11

what are the 3 main subgroups of inflammatory arthritis

Answer 11

rheumatoid arthritis
spondyloarthritis
crystal arthritis

Question 12

what are tests for osteoarthritis

Answer 12

Plain radiographs show: Loss of joint space, Osteophytes, Subarticular and subchonral cysts

CRP might be slightly elevated

Question 13

what is rheumatoid arthritis

Answer 13

A chronic systemic inflammatory disease, characterised by symmetrical, deforming, peripheral polyarthritis

Question 14

what does rheumatoid arthritis present with

Answer 14

• symmetrical swollen, painful, stiff small joints of hands and feet worse in the morning

Question 15

what are early signs of rheumatoid arthritis

Answer 15

• inflammation, symmetrical
• look for tenosynovitis or bursitis
• no joint damage

Question 16

what are later signs of rheumatoid arthritis

Answer 16

• joint damage
• deformity
• ulnar deviation and flexion of the wrists and fingers
• boutonnieres and swan neck deformities of fingers or z deformity of thumbs

Question 17

what are clinical correlations of rheumatic arthritis

Answer 17

• vague systemic features: malaise, fever
• generalised musculoskeletal pain
• symmetrical: swollen, warm, painful, limited movement in the morning and after inactivity
• small joint involvement before big joint involvement

Question 18

what is the progression of rheumatic arthritis

Answer 18

• Joint swelling. Decreased range of movement. Joint fusion (ankylosis)
• Associated involvement of tendons and ligaments
• Unstable, very limited ROM
• Synovial herniation - cysts
• Joint effusion

Question 19

what is the immunology of rheumatoid arthritis

Answer 19

• Autoimmune inflammation triggered
• CD4+T helper cells may be critical
• Cytokine production results from initiation of inflammation:

IFNg activates macrophages and synovial cells
IL-17 recruits neutrophils
TNF and IL-1 stimulate production of proteases from synoviam
RANKL expressed on activated T cells stimulates bone reabsorption

Question 20

what is panes formation

Answer 20

type of extra growth in your joints that can cause pain, swelling, and damage to your bones, cartilage, and other tissue

Question 21

what are some extra-articular manifestations of rheumatic arthritis

Answer 21

• nodules: elbows, lungs, cardiac…
• small vessel vasculitis
• ocular: keratoconjunctivitis
• lungs: pleural disease, interstitial fibrosis, bronchiolitis
• cardiac: pericarditis

Question 22

what is crystal arthropathies: gout

Answer 22

typically presents with monoarthropathy with severe joint inflammation. >50% occur in the metatarsophalangeal joint of the big toe

Question 23

how is hyperurucaemia synthesised

Answer 23

From purine catabolism

Reflects abnormal purine metabolism

Question 24

how is hyperurucaemia excreted

Answer 24

Renal filtration
Reabsorbed in proximal tubule
Limited excretion from distil tubule

Question 25

what can cause hyperuraeceamia

Answer 25

• usually idiopathic
• known enzyme defect - HGPRT deficiency
• increased cell turnover

Question 26

what are clinical manifestations of gout

Answer 26

• unclear how crystals end up in joint

- causes secondary degenerative changes in joint