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Flashcards in Demyelination and dementia Deck (60)
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1

What is demyelination?

Preferential damage to the myelin sheath
Relative preservation of the axons

2

What is the function of oligodendrocytes?

Locally confining neuronal depolarisation
Protecting axons
Forming nodes of ranvier

3

What are examples of primary demyelinating disorders?

MS
Acute disseminated encephalomyelitis
Acute haemorrhagic leukoencephalitis

4

What are examples of secondary demyelinating disorders?

Viral: PML
Metabolic: central pontine myelinolysis
Toxic: CO, organic solvents, cyanide

5

What is MS?

Auto-immune demyelination disorder characterised by distinct episodes of neurological deficits, separated in time and which correspond to spatially separated foci of neurological injury

6

What is required for the clinical diagnosis of MS?

Two distinct neurological deficits occurring at different times
A neurological deficit implicating one neuro-anatomical site and a MRI appreciated deficit at another neuro-anatomical site
Multiple distinct CNS lesions on MRI

7

What are tests that can be run in MS to support the diagnosis?

Visual evoked potentials; evidence of slowed conduction
IgG oligoclonal bands in CSF

8

What are the clinical features of MS?

Optic neuritis
Spinal cord lesions; motor or sensory deficit in trunk and limbs, spasticity, bladder dysfunction
Brain stem lesion: CN sign, ataxia, nystagmus, INO

9

Whatare the different types of MS?

Acute or insidious
Relapsing and remitting

10

What does MS look like morphologically?

White matter disease
Cut surface shows plaques

11

What are plaques in MS?

Well circumscribed, well demarcated
Irregular shaped areas
Glassy, translucent appearance
Vary from small to large
Non-anatomical distribution

12

What are frequently affected locations in MS?

Adjacent to lateral ventricles
Corpus callosum
Optic nerves and chiasm
Brainstem
Ascending and descending fibre tracts
Cerebellum
Spinal cord

13

What will active plaques show?

Perivascular inflammatory cells
Microglia
Ongoing demyelination

14

What will inactive plaques show?

Gliosis
Little remaining myelinated axons
Oligodendrocytes and axons reduced in number

15

Where are acute lesions commonly found?

Surrounding white matter

16

Where are chronic lesions commonly found?

Around lateral ventricles

17

What are the environmental factors of MS?

Assoc with latitude
Relationship with vit D deficiency
EBV viral trigger

18

What are the genetic risk factors for MS?

HLA DRB1

19

Why is MS classified as an immune mediated disease?

Lymphocytic infiltration in histology
Oligoclonal IgG bands in CSF
Genetic linkage to HLA DRb1

20

What are degenerative diseases of the cerebral cortex?

Alzheimer's
Pick Disease
CJD

21

What are degenerative diseases of the basal ganglia and brain stem?

PD
Progressive supranuclear palsy
Multiple system atrophy
Huntington's disease

22

What are degenerative diseases of the spinocerebellar system?

Friedreich Ataxia

23

What are degenerative diseases of the motor neurons?

MND

24

What is the pathogenesis of degenerative diseases?

Simple neuronal atrophy and subsequent gliosis

25

What is dementia?

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

26

What are the primary dementias?

Alzheimer's
Lewy body
Pick's disease
Huntington's

27

What are the secondary dementias?

Vascular dementia
Infection; HIV, syphilis
Tauma, metabolic
Alcohol
B1
Paraneoplastic syndromes
SOL
Chronic hydrocephalus

28

What is the commonest dementia?

Alzheimer's

29

What genes are implicated in alzheimer's?

Amyloid precursor protein (APP) - chromosome 21
Presenilin 1 - chromosome 14
Presenilin 2 - chromosome 1

30

What are the clinical features of alzheimer's disease?

Insidious impairment of higher intellectual function with alterations in mood and behaviour
Later: progressive disorientation, memory loss and aphasia