Pathology - Demyelination and Dementia

Question 1

what is demyelination?

Answer 1

preferential damage to the myelin sheath

Question 2

name three causes of primary demyelination

Answer 2

MS
acute disseminated encephalomyelitis (ADEM)
acute haemorrhagic leukoencephalitis (AHL)

Question 3

name three potential causes of secondary demyelination

Answer 3

viral illness
metabolic issues
toxins

Question 4

what is the most common demyelinating disease?

Answer 4

multiple sclerosis (MS)

Question 5

which sex is more commonly affected by MS?

Answer 5

females

Question 6

when does incidence of MS peak?

Answer 6

20-30 year olds

Question 7

what is MS?

Answer 7

an autoimmune demyelinating disorder characterised by distinct episodes of neurological deficit, separated in time

Question 8

how is MS diagnosed?

Answer 8

clinical diagnosis when there are two distinct neurological deficits occurring at different times

or

deficit implying one affected site and an MRI defect at another site

Question 9

what imaging can be done for MS and what is seen?

Answer 9

MRI

multiple distinct lesions, white on T2 weighted MRI

Question 10

what other investigations can be done to support a diagnosis of MS?

Answer 10

visual evoked potentials showing slowed conduction

IgG oligoclonal bands in CSF

Question 11

name the four forms of MS

Answer 11

clinically isolated
relapsing and remitting
primary progressive
secondary progressive

Question 12

describe the morphological appearance of the brain in MS

Answer 12

outside appears normal

cut surface shows plaques

Question 13

describe the appearance of the plaques formed in MS

Answer 13

well circumscribed, irregular shaped
translucent appearance
very in size

Question 14

name some areas frequently affected by plaques in MS

Answer 14

adjacent to lateral ventricles
corpus callosum
optic nerves 
brainstem 
cerebellum
spinal cord

Question 15

name some degenerative diseases that affect the cerebral cortex

Answer 15

alzheimer’s
pick disease
CJD

Question 16

name some degenerative diseases that affect the basal ganglia and brainstem

Answer 16

parkinson’s
progressive supranuclear palsy
multiple system atrophy
huntington’s

Question 17

what is dementia?

Answer 17

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

Question 18

name four types of primary dementia

Answer 18

huntington’s
pick’s disease
lewy body dementia
alzheimer’s

Question 19

what is the most common cause of dementia in the elderly?

Answer 19

alzheimer’s

Question 20

is alzheimer’s more common in males or females

Answer 20

twice as common in females

Question 21

name some implicated genes in familial alzheimer’s

Answer 21

amyloid precursor protein (APP)

presenilin 1+2

Question 22

how does alzheimer’s present?

Answer 22

insidious impairment of higher intellectual function with alterations in mood and behaviour

Question 23

what often causes death in patients with alzheimer’s?

Answer 23

secondary causes like bronchopneumonia

Question 24

what macroscopic changes are seen in alzheimer’s?

Answer 24

cortical atrophy
wide sulci + narrow gyri
dilatation of ventricles

Question 25

where in the brain is affected by cortical atrophy in alzheimer’s?

Answer 25

frontal, temporal and parietal lobes

Question 26

what microscopic changes are seen in alzheimer’s?

Answer 26

neuronal loss
neurofibrillary tangles
neuritic plaques
amyloid angiopathy

Question 27

how does lewy body dementia present?

Answer 27

progressive dementia
hallucinations
fluctuating attention + cognition
parkinsonism

Question 28

what is the pathology behind lewy body dementia?

Answer 28

degeneration of the substantia nigra

Question 29

what macroscopic changes are seen in lewy body dementia?

Answer 29

pallor in the substantia nigra

Question 30

what microscopic changes are seen in lewy body dementia?

Answer 30

loss of pigmented neurons
reactive gliosis
lewy bodies - spread from brainstem to cortex

Question 31

what is another name for pick’s disease?

Answer 31

fronto temporal dementia

Question 32

how does pick’s disease present?

Answer 32

progressive dementia commencing in middle life characterised by changes in character and social deterioration leading to impairment of intellect, memory and language

Question 33

what macroscopic changes occur in pick’s disease?

Answer 33

extreme atrophy of the cerebral cortex in frontal and temporal lobes

brain weight <1kg

Question 34

what can be seen on histology in pick’s disease?

Answer 34

neuronal loss
gliosis
pick’s cells
pick’s bodies

Question 35

what are pick’s cells?

Answer 35

swollen neurones

Question 36

what are pick’s bodies?

Answer 36

intracytoplasmic filamentous inclusions

Question 37

when does huntington’s tend to come on?

Answer 37

35-50

can occur at any time though

Question 38

what is the triad of clinical features of huntington’s?

Answer 38

emotional, cognitive and motor disturbances

Question 39

how is huntington’s inherited?

Answer 39

autosomal dominant pattern

mutation in the huntingtin gene on chromosome 4 - increased number of CAG repeats

Question 40

what macroscopic changes are seen in huntington’s?

Answer 40

atrophy of the basal ganglia, caudate nucleus and putamen

later on can have frontal, parietal and cortical atrophy

Question 41

what is a secondary dementia?

Answer 41

when another disorder gives rise to dementia

e.g, vascular dementia due to multiple infarcts