Week 1 Flashcards
(77 cards)
1
Q
Main types of arthritis
A
Osteoarthritis
RA
Infectious
Spondyloarthropathies.
2
Q
Which type f joint does arthritis attack?
A
- synovial
- joint space that allows movement
- e.g. knee, shoulder
3
Q
Describe osteoarthritis
A
- degeneration of articular cartilage due to aching and biomechanical stress
4
Q
Early Path Changes in Arthritis
A
- damage to cart
- clusters if xhrondrocyres
- small cart fissures
5
Q
Histology of OA Cartilage
A
- can see small fissure in cartilage
- fibrillation
- eventually cartilage disappears
6
Q
Radiological Correlations of Arthritis
A
- loss of joint space/cart loss
- subchondral sclerosis/eburnation
- subchondral cysts/syno fluid conjugation
7
Q
Describe rheumatoid arthritis
A
- AI, younger, female, systemic
- extra articular lesions are common (even without joint symptoms)
- progressive disease but can show periods of remission
8
Q
Pres of rheum arthritis
A
- systemic (malaise and fever)
- gen MSK pain
- joint involvement becomes more
- symmetrical swelling, warmth, pain, worse in morning
- small joints before large
9
Q
Causes of RA
A
- genetic
- HLA DRB1
- AI inflam
- environmental
- smoking, infections
10
Q
What happens in RA acute phase?
A
Pannus formation
Hyperplastic and reactive changes in synovium
Results in cart destruction and acute symptoms
11
Q
What happens in RA chronic phase?
A
Joints begin to fibrose and become deformed
More severe and debilitating symptoms
12
Q
Examples of extra-articular manifestations of RA
A
Skin - rheumatoid nodules
Ocular - keratoconjunctivitis
Oral - saliv gland swelling
GI - mesenteric vasculitis
Pulm - pleurisy
Cardiac - endocarditis
Renal - glomerulonephritis
Neuro - periph neuropathy
Haem - anaemia
13
Q
Describe spondyloarthritides
A
Ankylosing - destructive process, bony fusion around joints
Reactive and enteris - AI vs infective
14
Q
Describe psoriatic arthritis
A
> 10% pts
Hands and feet esp
Asymmetrical
15
Q
Describe infectious arthritis
A
Haematogenous spread of orgs
Single joint
Systemic infective features, aspirate purulent fluid
E.g. mycobacterium, Lyme’s disease, viral
16
Q
Two main types of crystal arthropathy
A
Gout - urate metabolism
Pseudo-gout - calcium oyrophosphate
17
Q
Describe hyperuricaemia
A
Urate is by-product of purine catabolism
Excreted renally
Usually idiopathic or enzyme HGPRT defic
18
Q
How does hyperuricaemia lead to crystal arthopathy?
A
Crystals settle in joint spaces
Esp in joints of lower temperatures (feet etc)
Long history of hyperuri predisposes to gout/arth
Mimics infective arth
19
Q
Clin pres of hyperuricaemia
A
Secondary degen of joint
Despos of crytslas in soft tissues (gouty tophus)
Renal disease (stones, direct depos in tubules/IS tissue)
20
Q
Describe calcium oyrophosphate arthropathy manifestations
A
Larger joints, often asympto
Joint pain is varied
Less inflam than gout (50% cases have sig joint damage)
21
Q
Phys function of skeletal muscle
A
Maintenance of posture
Purposeful movement in relation to external environment
Respiratory movements
Heat production
Contribution to whole body metabolism
22
Q
How can you ID muscle striation?
A
Under a light microscope as alternating dark bands (caused by myocin thick filaments) and light bands (caused by actin thin filaments)
23
Q
Striated vs unstriated
A
Stri - skeletal, cardiac
Un- smooth
24
Q
Voluntary vs involuntary control of muscles
A
Vol - skeletal
Invol - cardiac, smooth
25
Define the motor unit
The motor unit is a single alpha motor neuron
and all the skeletal muscle fibres it innervates
26
Fewer muscle fibres per motor unti corresponds with?
Muscles serving finer movements e.g intrinisc hand muscles and extra-ocular muscles
27
E.g. where power more important than precision?
Thigh muscles
28
What is myofibril?
These are specialised contractile intracellular structures
The predominant structure of
skeletal muscle fibre
29
What is the functional unit of an organ?
the smallest component capable of performing all the functions of that organ
30
4 sarcomere zones
(Found between 2 Z lines)
A band
H zone
M line
I band
31
Define excitation contraction coupling
the process whereby the surface action potential results in activation of the contractile structures of the muscle fibre
32
Factors affecting tension developed by contracting muscle fibres
- frequency of stimulation and summation of contractions and
- length of muscle fibre at the onset of contraction
- thickness of muscle fibre
33
How can a stronger contraction be created?
summation of twitches, repetitive fast stimulation of skeletal muscle giving it no time to relax
34
Difference between isotonic and isometric ocntractions
Isotonic contraction: used for (1) body movements and for (2) moving objects. Muscle tension remains constant as the muscle length changes
Isometric contraction: used for (1) supporting objects in fixed positions and for (2) maintaining body posture. Muscle tension develops at constant muscle length
35
3 types of joints
Synovial
FIbrous
Cartilinigous
36
Describe fibrous jounts
Bones united by fibrous tissue
Doesn’t allow any movement
Example are bones of the skull in adults
37
Describe cartilaginous joints
Bones united by Cartilage
Allow limited movement
Examples are Intervertebral Discs; Pubic symphsis; Part of the sacroiliac joints; Costochondral joints
38
Describe synovial joints
Bones separated by a cavity (containing synovial fluid) and united by a fibrous capsule lined w synovial membrane
The articular surfaces of bones are covered with cartilage
39
2 types of synovial joints
Simple - one pair art surface
Compound - >1 pair art surface
40
Roles of joints in purposeful motion
Stress distribution
Confer stability (aided by joint shape)
Joint lubrication (IS fluid, synovium)
41
Functions of synovial fluid
Lubricates Joint
Facilitates joint movements - reduces friction
Minimise wear-and-tear
Aids in the nutrition of articular cartilage
Supplies chondrocytes with O2 and nutrients, removes CO2/waste products
42
Features of synovial fluid
Continually replenished
High viscosity (hyalauronic acid, varies w movement)
Contains few cells
43
Changes in synovial fluid during joint movement
Rapid movement is associated with decreased viscosity and increased elasticity
These properties of synovial fluid become defective in a diseased joint e.g. in osteoarthritis
44
Abnormal synovial fluid???
Red - traumatic synovial tap, haemmorhagic arth
Incr WBC - inflam and septic arth
45
Function of articular cartilage
Provides a low friction lubricated gliding surface (no wear and tear)
Distributes contact pressure to subchodral bone
(determined by mech properties of cart)
46
Features of articular cart
Hyaline, elastic. sponge-like
Extracellular matrix (made by chondrocytes) - water, collagen, proteoglycans (decr with age)
47
Role of water, collagen and proteoglycan in ECM
Water - resiliency, strength, nutrition and lubrication system
Collagen - tensile strength and stiffness
Proteoglycan - compressive props w load bearing
48
How can joint disease occur with regards to ECM?
Joint disease can also occur if the rate of ECM degradation exceeds the rate of its synthesis
49
What are the catabolic and anabolic factors of cartilage matrix turnover?
Catabolic - Stimulate proteolytic enzymes and inhibit proteoglycan synthesis (IL-!)
Anabolic - Stimulate proteoglycan synthesis and counteract effects of IL-1 (IGF-1)
50
What can go wrong in a joint?
Cartilage and synovial composition deteriorate, repeated wear and tear - osteoarthritis
Synovial cell proliferation/inflammation - RA
Deposition of salt crystals - gout
Injury/inflammation to periarticular structures, soft tissue rheumatism - tendonitis
51
Descrube osteomyelitis
Inflammation of bone and medullary cavity, usually located in one of the long bones.
Hametogenous (monobac) - adults (vert), kids (longs)
Contiguous (polimicro) - kids (inj,surg), old (press sore, vasc insuff), DM (ST inf, neuropathy)
52
Clin pres of chronic and acute osteomyelitis
Acute - abrupt onset intense pain, +/- erythema, chronic discharging sinus, sympto few days/weeks
Chronnic -long infection months/years, sequestra
53
Management of osteomyelitis
Perc aspirate, deep surg cultures
Sinus drain if staph or resistant orgs
Antibios before culture if septic, ST infection
54
Types of osteomyeltis
Open fractures (staph A, gm-, aggressive debridement)
Diabetes/ Vascular insufficiency/ neuropathy (gm+, debridement/antimicros)
Haematogeneous osteomyelitis (PWID, kids, lines, staph gm+
Vertebral osteomyelitis (disc space infection, treatment path spec, drainage!!!, skeletal TB)
Specific hosts and pathogens
Unusual groups (sickle cell, gauchers)
55
Define epi/peri/endomysium
Epi - CT that surrounds the muscle as a whole
Peri - CT around a single fascicle
Endo - CT around a single muscle fibre is the endomysium
56
3 types of skeletal muscle
Type I: relatively slowly contracting fibres that depend on oxidative metabolism.
Type IIA: relatively fast contracting, but are also reasonably resistant to fatigue.
Type IIB: fast contracting fibres that depend on anaerobic metabolism.
57
Examples of non-neoplastic bone disease
Osteoporosis
Osteomalacia
Hyperparathroidism
Avascular necrosis
Paget’s Disease
58
Osteoporosis can be secondary to...
Endocrine - Cushing's
GI - malabs
Drugs - corticosteroids
Misc - immobilisation
59
Main cause of osteomalacia?
Vit D defic (malabs, insuffiecient sun exp)
Leads to hypocalcaemia and elevated PTH
Bone becomes weakened and prone to fracture
60
Describe avascular necrosis
Necrosis of bone and marrow
The result of loss of effective vascular supply
Can result from fractures (scaphoid, femoral head)
Caused by e.g. alc, steroid, decomp, SC, CT disorder
61
Describe hyperparathyroidism
Incr secretion of PTH activates osteoclasts which elevates serum calcium
Causes osteoporosis,brown tumours, osteitis fibrosa cystica
62
Describe Paget's disease
Asympto abnormality of bone turnover
Causes - genetic (RANKL), viral (measles, RSV)
Results in - thick excess bone with abnormal reversal lines (mosaic pattern), Bone matures but is soft and porous
63
3 stages of Paget's
Osteolytic
- Resorption pits with large osteoclasts
Mixed
- Osteoclasis and osteoblastic activity
Osteosclerotic.
64
Most common orgs of prosthetic infection
Shoulder - coag neg staph
Hip/knee - gm pos coag neg staph (aureus!!!!), strep, enterococcus, E coli
65
Define biofilm
Microbe-derived sessile community
66
Treatment of coag neg staph PJI infection?
Vancomycin
67
Describe septic arthritis
Inflammation of the joint space caused by infection.
Can be - blood borne, local infection, direct inoculation
Staph aureus!!!!!
Joint fluid - culture, microscopy (exclude crystals)
68
Treatment of staph aureus septic arthritis/
Flucloxacillin!!!!! (ceftriaxone if <5)
69
Microbes assoc w pyomyositis (skeletal muscle abscess)
90% staph
Psuedomonas, beta haem strep, enterococcus, clostridial
70
Describe mynecrosis
Clostridial gas gangrene of an extremity, spontaneous or secondary to injury
Pitfalls - Absence of fever, cutaneous manifestations, pain/syst syptoms attributed to trauma or other causes
71
Describe tetanus
Gm +ve anaerobic spores,
Causes spastic paralysis - Lock Jaw, trismus, risus sardonicus
Treatment - debridement, antitoxin, supposrtive, vax, survivors NOT IMMUNE
72
Cause of myasthenia gravis
Myasthenia gravis is caused by autoantibodies to the nAChR – since the antigen-antibody complex has a half life of 2 days, this means that there is progressive loss of functional nAChR’s
Thymus is hyperplastic and so produces these autoantibodies.
ACh inhibitors - symptom management
73
4 processes in physiology of pain
Transduction - noxious stim -> elec activity
Transmission - nerve impulse propagated
Modulation - mod of pain transmission e.g. NTs
Perception - conscious experience
74
What is a nociceptor?
Sensory afferent neurons normally activated by intense noxious stimuli
First order neurons that relay info to second orders via synaptic transmission
75
2 types of second order neurones in terms of pain response
STT - pain perception (location, intensity)
SRT - autonomic response (pain, arousal, emotion, fear)
76
How can pain be classified?
Mechanisms - nociceptive/inflam/path
Time course
Severity
Source of origin
77
Describe the 3 types of mechanical pain
Nociceptive - injury to tissue by nox stim, only from intense stim, adaptive, early warning
Inflam - activ of immune syste by injury/infection, heightened pain sensitivity to nox stim, adaptive
Path - dysfunctional (no ID damage: IBS, fibro, maladaptive), referred (distant from origin site)
