6 - multiple sclerosis and inflammation Flashcards

1
Q

fill this in for the action potential in neurones

A
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2
Q

describe the Node of Ranvier

A
  • no myelin sheath
  • where Na+ channels are located
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3
Q

what is the composition of the myelin sheath?

A

lipids
> galactocerebroside

glycoproteins
> myelin basic protein (MBP)
> myelin oligodendrocyte glycoprotein (MOG)
> myelin associated glycoprotein (MAG)

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4
Q

how does conduction speed differ in unmyelinated vs myelinated axons?

A

0.5-10 m/s for unmyelinated vs 150 m/s for myelinated

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5
Q

what is multiple sclerosis?

A

slow progressive CNS disease characterised by destruction of the myelin sheath around the axons in the brain and spinal cord

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6
Q

multiple sclerosis is an immune attack against what?

A

oligodendrocyte (and/or Schwann cells)

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7
Q

what does the immune attack in MS lead to?

A

several neurological symptoms, including loss of sensations (touch, taste), motor coordination impairment, vision impairment (involuntary eye movement)

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8
Q

where can pathology occur in MS?

A

white AND grey matter — lesions occur all over the CNS

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9
Q

what is the clinical-radiological paradox?

A
  • some have few lesions but lots of disability
  • some have lots of lesions but not as much disability

new lesions are not always linked to relapses

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10
Q

what are some symptoms and signs of lesions in the cerebrum?

A

symptoms:
- cognitive impairment (decreased processing speed, decreased memory)
- sensory and motor deficit
- depression
- seizures (rare)
- focal cortical deficit

signs:
deficit in attention, reasoning and executive function (early), dementia (late), upper motor neurone signs

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11
Q

what are some signs and symptoms of lesions in the optic nerve?

A

symptoms:
- loss of vision
- delayed VEP (visual evoked potential)

signs:
- scotoma
- reduced visual acuity
- colour vision
- pupillary defect

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12
Q

what are some signs and symptoms of lesions in the cerebellum and cerebellar pathways?

A

symptoms:
- tremor
- clumsiness, poor balance

signs:
- postural and action tremor
- dysarthria
- limb in coordination
- gait ataxia

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13
Q

what are some signs and symptoms of lesions in the brainstem?

A

symptoms:
- vertigo
- impaired speech
- impaired swallowing

signs:
- dysarthria (difficulty speaking)

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14
Q

what are some signs and symptoms of lesions in the spinal cord?

A

symptoms:
- weakness
- stiffness and spasms

signs:
- upper motor signs
- spasticity

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15
Q

what is spasticity?

A

an abnormal increase in muscle tone or stiffness of muscle

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16
Q

lesions in where is a bad prognostic marker?

A

spinal cord

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17
Q

describe benign MS

A
  • 10-20% of all MS patients
  • very short episodes of mild neurological symptoms
  • symptoms do not worsen during subsequent attacks
  • return to normal between attacks
18
Q

describe relapsing remitting / relapsing persistent MS

A
  • 85-90% of all MS patients
  • unpredictable attacks (relapses) lasting 24 hours or more followed by periods of months to years of improvement (remission) with no new signs of disease activity
  • the period between attacks may decrease
  • symptoms become more severe
19
Q

describe relapsing-remitting followed by secondary progression MS

A
  • after 20 years, roughly 50% of those with initial relapsing-remitting MS will have developed secondary progression MS (SPMS)
  • this decline may include more severe neurological symptoms, worsening cognitive function, or other deficits
  • gradient of slope can differ between people
20
Q

describe primary chronic progression MS

A
  • describe the approx 10% of individuals who never have remission after their initial MS symptoms
  • decline occurs continuously without clear attacks
  • affects people who are older at disease onset
21
Q

disability is most commonly measured using what?

A

the expanded disease severity scale, EDSS

22
Q

when is MS typically diagnosed?

A

between the ages of 20-40

23
Q

men : woman MS prevalence

A

1 : 3.5

24
Q

where are prevalence rates of MS higher geographically?

A
  • further away from the equator
  • in northern parts of european countries
25
Q

what is the chance of both twins developing MS if one twin does for monozygotic and dizygotic twins?

A
  • monozygotic — 25% chance
  • dizygotic — 3% chance
26
Q

in MS, there is a genetic association with which chromosome? what does this also contain?

A
  • chromosome 6
  • also contains MHC class genes and myelin proteins
27
Q

what viruses have been implicated in MS pathogenesis?

A

hepatitis B, Epstein Barr virus

28
Q

what is the blood brain barrier?

A
  • membrane that controls the passage of substances from the blood into the CNS
  • physical barrier (tight junctions of endothelial cells) between the local blood vessels and smooth parts of the CNS
29
Q

what is the CNS normally inaccessible to and why?

A

T cells due to BBB

30
Q

on an MRI, what do white lesions indicate?

A

areas of inflammation and open BBB

31
Q

what can be seen on MRI apart from lesions?

A

brain atrophy with widened lateral ventricles and cortical sulci

32
Q

why can diagnosis be harder for primary progressive MS?

A

few lesions, no clinical relapses

33
Q

what can lesions represent on T2-weighed MRI scan?

A
  • demyelination
  • inflammation
  • axonal loss (particularly when visible as “black holes” on T1-weighted imaging)
  • gliosis
  • remyelination
  • oedema
34
Q

what can lesions represent in T1-weighted MRI scans?

A

axonal loss and demyelination

35
Q

cerebrospinal fluid protein electrophoresis shows what in mroe than 90% of MS cases? what is this particularly useful for?

A
  • oligoclonal IgG (gamma-globulin) bands — underlying inflammatory pathology
  • particularly useful for primary progressive MS where there are few lesions and relapses
36
Q

what are visual evoked potentials (VEPs) like in patients with MS?

A

delayed and reduced

37
Q

what us a common cause of delayed VEP in MS?

A

optic neuritis (lesions in optic nerve/tract)

38
Q

what is the prognosis for those with fewer lesions on MRI at clinically isolated stage (CIS)?

A

lower risk of developing disability

39
Q

lesions in where predict greater disability in greater stages?

A

infratentorial lesions

40
Q

there are worst cognitive outcomes in MS in who?

A

men

41
Q

worst EDSS outcomes in who?

A

those with primary progressive MS and those who present with high EDSS