6.06 - Multiple Sclerosis, Vision Loss

Front 1

What is the most common cause of neurological disability in young adults?

Back 1

Multiple sclerosis

Front 2

Is relapsing, remitting MS more common in men or women?

Back 2

Women, approximately F:M 2:1.

Front 3

What is the average decade of onset of MS?

Back 3

The average age of onset of MS is 34 yo so the fourth decade of life.

Front 4

Is MS more or less common at high latitudes?

Back 4

In general, more common.

Hint 4

Some research suggests this link may be due to higher sun exposure and thus Vitamin D levels in populations closer to the equator.

Front 5

In general, will MS lesions be detectable on MRI before they become symptomatic?

Back 5

Yes. As MRI resolution improves increasingly small MS lesions can be identified.

Hint 5

However MR imaging of the brain is not routine and thus this lesion activity might only be discovered incidentally rather than as part of a screening program.

Front 6

Are MS lesions found in the white matter or grey matter of the cerebrum?

Back 6

Both.

Hint 6

While MS lesions involve demyelination and thus are more often found in the normally-myelinated white matter of the brain, myelin is also found in the grey matter and so lesions are also found here albeit less commonly.

Front 7

Does MS involve axonal destruction?

Back 7

Yes. Although relative sparing of axons is typical of MS, partial or total axonal destruction can also occur, especially within highly inflammatory lesions.

Front 8

Name four typical symptoms of MS at disease onset.

Back 8

1. Weakness
2. Optic neuritis
3. Sensory disturbances
4. Unsteady gait

Hint 8

Other typical symptoms include:
vertigo, diplopia and sphincter disturbance

Front 9

In the context of MS, what is Uhtoff's phenomenon?

Back 9

The worsening of neurologic symptoms in multiple sclerosis (MS) and other neurological, demyelinating conditions when the body gets overheated from hot weather, exercise, fever, or saunas and hot tubs.

Front 10

Why do neurologic symptoms in MS worsen when the body is heated (Uhtoff's phenomenon)?

Back 10

It is possibly due to the effect of increased temperature on nerve conduction. With an increased body temperature, nerve impulses are either blocked or slowed down in a damaged nerve but once the body temperature is normalized, signs and symptoms may disappear or improve.

Front 11

Is a benign course of MS more or less likely if it begins late in life?

Back 11

Less likely. A benign course is more likely with an early age onset.

Front 12

What fraction of MS patients will need assistance with walking after 10 yrs?

Back 12

Half.

Front 13

How does the signal of an MS lesion appear on T2/FLAIR sequence MRI?

Back 13

As a high signal intensity (bright) lesion.

Front 14

Where are MS lesions typically seen on MRI?

Back 14

Bordering lateral ventricles, in the corpus callosum, brain stem, cerebellum and spinal cord.

Front 15

What is the advantage of a Gd enhanced MRI study in MS?

Back 15

Gd enhanced lesions indicate current sites of inflammation, BBB breakdown rather than old lesions.

Front 16

How does the serum level of complement regulator factor H vary between progressive MS and relapsing-remitting MS?

Back 16

Serum factor H levels are higher in progressive MS.

Hint 16

This biomarker may begin to be used as a stratifying tool in determining disease course.

See Brain. 2010 Jun;133(Pt 6):1602-11. Epub 2010 Apr 25.

Front 17

In the context of MS, what are shadow plaques?

Back 17

Shadow plaques are areas where axons have been remyelinated by surviving oliogdendrocytes or those that differentiate from precursor cells after an acute MS attack.

Front 18

If an adult moves from an area of high MS prevalence to an area of low MS risk (or vice versa), will their risk be that of their old region or the new one?

Back 18

The risk will be that of their old region. Conversely, when individuals move prior to their adolescent years, their risk becomes becomes similar to the region to which they move.

Front 19

Does the use of IV corticosteroids in acute MS attacks improve the eventual state of the lesion?

Back 19

No, however the use of steroids in does hasten the patient's recovery.

Front 20

Where are the cell bodies of optic nerve axons located?

Back 20

In the retina, as they are axons of retinal ganglion cells.

Front 21

Where do the majority (90%) of retinal ganglion cell axons project to?

Back 21

The lateral geniculate nucleus, in the thalamus.

Front 22

Explain which retinal fibres decussate at the optic chiasm.

Back 22

There is a partial decussation of fibres, so that axons originating in the nasal half of each retina cross over at the optic chiasm to innervate the contralateral half of the brain, where as axons from the temporal half of each retina innervate the same (ipsilateral) side of the brain.

Front 23

What visual defect would occur if the left optic tract was severed?

Back 23

The optic tract is the post-chiasmatic continuation of the optic nerve. Severing the left optic tract causes loss of the right hemifield of vision, a right homonymous hemianopia.

Front 24

What kind of visual field defect might a pituitary tumour cause, and why?

Back 24

Since the pituitary gland sits directly anterior to the optic chiasm, a pituitary tumour may compress the optic nerve fibres decussating here. Thus there may be a loss of the visual fields from the nasal halves of each retina and thus a bitemporal hemianopia.

Front 25

What sort of visual information do parvocellular layer cells transmit?

Back 25

Parvocellular layer cells transmit information about the colour and spatial detail of objects in the visual field.

Front 26

What sort of visual information do magnocellular layer cells transmit?

Back 26

Magnocellular cells transmit information about movement and the borders between different objects.

Front 27

Is a posterior cerebral artery (PCA) stroke more or less common than stroke involving the anterior circulation?

Back 27

Less common.

Front 28

Where do the posterior cerebral arteries usually arise from?

Back 28

The top of the basilar artery.

Front 29

Approximately what percentage of MS patients have a relapsing-remitting course of the disease?

Back 29

80%.

Front 30

In an MS relapse, over what time period do signs and symptoms typically evolve: minutes, hours, days or weeks?

Back 30

In relapsing remitting MS, symptoms and signs typically evolve over several days and then stabilise

Front 31

Following an MS relapse over what time period do symptoms and signs improve: hours, days, weeks or months?

Back 31

Symptoms improve within weeks.

Front 32

What treatment is indicated in an acute relapse of MS?

Back 32

Corticosteroids.