Neuropathology 3: Dementia and Demyelinating Disorders Flashcards Preview

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Flashcards in Neuropathology 3: Dementia and Demyelinating Disorders Deck (57)
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1
Q

how do oligodendrocytes facilitate saltatory conduction?

A

by forming nodes of ranvier

2
Q

demyelination causes defects in the __ and ___ of neuroconduction

A

rate

consistency

3
Q

axons are preserved in demyelinating disorders T or F

A

T

4
Q

multiple sclerosis is a primary cause of demyelination T or F

A

T

5
Q

name secondary causes of demyelination

A

viral eg leukoencephalopathy
metabolic eg central pontine myelinosis
toxic eg CO, solvents

6
Q

primary causes of demyelination

A

MS
acute disseminated encephalomyelitis (ADEM)
acute haemorrhagic leukoencephalomyelitis

7
Q

patient with hyponatraemia that is overly corrected can cause…

A

central pontine myelinosis

8
Q

lesions in MS occur in the __ matter; why?

A

white

this is the area of the brain with myelinated axons

9
Q

what is found in CSF in an MS patient?

A

IgG oligoclonal bands

10
Q

visual impairment is __lateral in optic neuritis?

A

uni

11
Q

MS is primarily a disease of the __ matter

A

white

12
Q

the lesions are mainly on the outside of the brain in MS T or F

A

F, in middle

13
Q

what do the lesions in MS look like?

A

glassy, thin

non symmetrical

14
Q

where are MS plaques found?

A
periventricular white matter
corpus callosum
optic nerves and chiasm
brainstem
spinal cord
15
Q

active plaques show evidence of…

A

inflammatory cells
microglia
active demyelination

16
Q

what do demyelinating plaques look like?

A

yellow/brown with an ill defined edge that blends into the surrounding white matter

17
Q

chronic plaques show evidence of..

A

gliosis
loss of myelin
less oligodendrocytes and axons

18
Q

what do inactive plaques look like?

A

well demarcated grey brown lesions located around the lateral ventricles

19
Q

does MS have a genetic component?

A

yes, 15x risk if 1st degree relative

20
Q

MS has genetic linkage to what gene complex?

A

HLA DR2

21
Q

what degenerative diseases affect the cerebral cortex?

A

alzheimers
CJD
pick disease

22
Q

main pathological process in degenerative disease?

A

simple neuronal atophy

subsequent gliosis

23
Q

what degenerative diseases affect the brainstem and basal ganglia

A

parkinsons

huntingtons

24
Q

define dementia

A

acquired and persistence generalised disturbance of higher mental functions in an otherwise fully alert person

25
Q

dementia is part of the normal ageing process T or F

A

F, always pathological

26
Q

dementias tend to present symmetrically T or F

A

T

27
Q

name primary dementias

A

alzheimers
lewy body
vascular
frontotemporal

28
Q

alzheimers tends to present after age __

A

60

29
Q

is alzheimers familial?

A

not really, only about 1%

30
Q

what gene is said to be implicated in alzheimes?

A

amyloid precursor protein

31
Q

how does alzheimers progress?

A

onset is subtle but once symptoms begin the patient deteriorates quickly with disorientation and memory loss

32
Q

what happens to the appearance of the brain in alzheimers?

A

cortical atrophy
widening of sulci and narrowing of gyri
frontal, temporal and parietal lobe atrophy

33
Q

what parts of the brain are NOT affected in alzheimers?

A

brainstem

cerebellum

34
Q

classic microscopic appearance of alzheimers

A

neuronal loss -> gliosis
neurofibrillary tangles (aggregates of tau protein) are characteristic
amyloid plaques

35
Q

what genetic condition is associated with early onset of alzheimers?

A

down syndrome

36
Q

name the protein responsible for creating neurofibrillary tangles

A

tau protein

37
Q

main component of amyloid plaques? how do they kill neurons

A

amyloid beta

promote excitotoxicity

38
Q

what amyloid disease are alzheimers patients at risk of?

A

amyloid angiopathy (disrupts BBB)

39
Q

describe lewy body dementia; how is it different from alzheimers?

A
progressive dementia WITH:
hallucinations
fluctuating attention and cognition
REM sleep disorder (acting out dreams)
parkinsonism

NB memory loss occurs much later

40
Q

why do you get parkinsonism in lewy body dementia?

A

lewy body affects the nigro striatal dopaminergic pathways

41
Q

main pathological process in lewy body dementia

A

degeneration of the substantia nigra due to gliosis of dopaminergic neurons

42
Q

microscopic appearance of lewy body dementia

A

lewy bodies (discrete eosinophilic lesions surrounded by a pale halo)
reactive gliosis
loss of pigmented neurons

43
Q

main age of onset in huntingtons?

A

35-50

44
Q

name the triad of symptoms in huntingtons?

A

triad of emotional, cognitive and motor disturbance

45
Q

symptoms in huntingtons?

A
chorea
myoclonus
clumsiness
slurred speech
depression
irritability
dementia develops MUCH LATER
46
Q

what chromosome carries the huntington gene?

A

4

47
Q

dementia is an early feature of huntingtons T or F

A

F, occurs much later

48
Q

main pathological process in huntingtons - be specific

A

atrophy of the caudate nucleus in the basal ganglia

frontal and parietal atrophy

49
Q

microscopic appearance of huntingtons

A

degenerations of striatal neurons in the caudate nucleus

gliosis

50
Q

frontotemporal dementia is also called…

A

picks disease

51
Q

what dementia is known to begin early (in middle life)

A

fronto-temporal

52
Q

fronto-temporal dementia macroscopic appearance?

A

extreme atrophy of cerebral cortex starting in frontal and later affecting the temporal lobesp

53
Q

what are picks cells? what do they present in?

A

swollen neurons

fronto-temporal dementia

54
Q

cerebrovascular dementia occurs due to what pathological process

A

hypoxia or anoxia

55
Q

you need to lose ___mls of brain before the dementia begins in CV dementia

A

50-100

56
Q

how does CV dementia differ from alzheimers?

A

abrupt onset rather than insidious
stepwise progression rather than smoothly progressive
history of CV problems eg HT/stroke

57
Q

classic macroscopic appearance of CV dementia

A

large vessel infarcts scattered through hemispheres with atheroma of large cerebral arteries