Demyelinating disorders

Question 1

Approximately what percentage of the brain consists of grey and white matter?

Answer 1

50% white matter
50% grey matter

Question 2

In a foetus, when does myelination begin?

Answer 2

In the third trimester with a rapid increase at birth.

Question 3

Which cells transform into oligodendrocytes?

Answer 3

Oligodendrocyte precursor cells

Question 4

The larger (thicker) the axon, the ___ wraps of myelin.

Answer 4

More.

Question 5

Spiral wrapping during myelination is dependent on which transmitters?

Answer 5

Gliotransmitters.

Question 6

For the formation of myelin in the PNS, proteins on an axon surface interact with glial cell receptors. What is an example of a protein and receptor that does this?

Answer 6

Neuroregulin 1 type 3 protein
Erb b receptor

Question 7

Prior to a signal moving from one node of ranvier to another, the axon depolarises and what ion channel opens?

Answer 7

Na+.

Question 8

An action potential is generated following axon depolarisation and the opening of Na+ channels. How does this axon repolarise?

Answer 8

By the opening of K+ channels.

Question 9

What is demyelination?

Answer 9

Damage and loss of the myelin sheath, leading to the slowing or blocking of nerve messages.

Question 10

What is leukodystrophy?

Answer 10

A condition where there is a failure to myelinate axons.

Question 11

Multiple sclerosis is caused by demyelination in which nervous system?

Answer 11

Central.

Question 12

Which environmental factor is linked to multiple sclerosis?

Answer 12

Lack of sun/vitamin D exposure

Question 13

Which infection has been linked to multiple sclerosis?

Answer 13

EBV

Question 14

Which gender is more commonly affected by multiple sclerosis?

Answer 14

Female

Question 15

Which modifiable risk factors are associated with multiple sclerosis?

Answer 15

Smoking
Obesity

Question 16

In multiple sclerosis, which cells enter the brain and attack myelin?

Answer 16

Immune T cells

Question 17

During a remission in multiple sclerosis, what is happening to axons?

Answer 17

They’re being remyelinated.

Question 18

Does everyone recover from multiple sclerosis?

Answer 18

No - can go onto a secondary progressive phase.

Question 19

Demyelination in different areas of the CNS will still cause the same symptoms. T/F?

Answer 19

False

Question 20

What different symptoms are associated with multiple sclerosis?

Answer 20

Question 21

In multiple sclerosis, what feature is common on imaging?

Answer 21

Presence of short segmental lesions/multiple sclerotic lesions.

Question 22

Which of the 5 senses is commonly affected at the start of multiple sclerosis?

Answer 22

Vision

Question 23

Difficulties with balance, coordination + tremor are common in multiple sclerosis. Where do these originate from in the brain?

Answer 23

Cerebellum.

Question 24

In multiple sclerosis, the spinal cord is commonly affected. What type of symptoms could this cause?

Answer 24

Change in sensation
Loss of strength (weakness, spasticity, brisk reflexes)
Bladder + bowel problems.

Question 25

In multiple sclerosis, the optic nerve is commonly affected. Which painful eye condition can this lead to?

Answer 25

Optic Neuritis

Question 26

What are the common symptoms of optic neuritis?

Answer 26

Reduced vision - central/colour Pain on eye movement Reduced visual acuity (objects/shapes) Swollen optic disk

Question 27

What is Lhermitte's sign?

Answer 27

Sign of MS. Put head down + get shooting pains down spine or into arms.

Question 28

Which scale is used to measure disability?

Answer 28

Expanded Disability Status Scale.

Question 29

How is an acute episode of MS treated?

Answer 29

With steroids

Question 30

Guillan-Barre Syndrome is a demyelinating disease in which nervous system?

Answer 30

Peripheral.

Question 31

What PNS demyelinating condition often follows after a recent infection?

Answer 31

Guillan-Barre Syndrome.

Question 32

What infections are linked to Guillan-Barre Syndrome?

Answer 32

Campylobacter URTI Hep E COVID

Question 33

What causes an infection to lead to Guillan-Barre Syndrome?

Answer 33

Antibodies made to fight the infection cross react and instead attack the myelin sheath. This is called molecular mimicry.

Question 34

What is another name for Guillan-Barre Syndrome?

Answer 34

Acute Demyelinating Polyradiculoneropathy.

Question 35

Which condition common in Asian countries affect the nerve, rather than the myelin?

Answer 35

AMAN Acute Motor Axonal Neuropathy.

Question 35

Which condition common in Asian countries affect the nerve, rather than the myelin?

Answer 35

AMAN Acute Motor Axonal Neuropathy.

Question 36

How does Guillan-Barre Syndrome typically progress?

Answer 36

Slowly over 2-4 weeks, reaches a peak at 4-6 weeks then usually recovers.

Question 37

In Guillan-Barre Syndrome, after recovery when are symptoms likely to present again?

Answer 37

Almost never - it's a monophonic illness. Only in a small minority of people do symptoms reoccur.

Question 38

How is Guillan-Barre Syndrome treated?

Answer 38

Supportive management IV immunoglobulin Plasma exchange