Chapter 23: multiple sclerosis

Question 1

Multiple sclerosis (MS)

Answer 1

A chronic neurological disorder that is characterized by inflammation and neurodegeneration (cell loss) in the central neurvous system. This causes a disruption of signal transmitssion and therefore loss of function.
The age of onset is between 20 and 40 years old and more women develop it than men (but men deteriorate faster).

Question 2

The cause of MS

Answer 2

The cause of MS is unknown, but there are some factors that do have an influence:
- Vitamin D deficiency
- Obesity at a young age
- Smoking
- An infection with the Epstein-Barr virus (Pfeiffer’s)
It’s not a genetic disorder, but the chance is 10-15 times bigger that you develop MS if one of your parents also has it.

Question 3

MS in the brain

Answer 3

Causes demyelination in the white and grey matter (seen in MRI), these places are called lesions.

Question 4

The outside-in hypothesis

Answer 4

The development of demyelinating lesions is accompanied by an immune response of the body: inflammation. The damage that is caused in the BBB causes immune cells (T and B cells) to enter the brain and attack the brain’s own myelin. This autoimmune response can be triggered by the loosening of myelin from the axon.

Question 5

Progressive relapsing MS

Answer 5

A gradual decline from the onset with periods of loss of function.

Question 6

Relapse-remitting MS

Answer 6

Periods of loss of function (relapse) are followed by full or near-full recovery (remission). The atrophy exists in the cortex and the thalamus.

Question 7

Secondary progressive MS

Answer 7

Relapse-remitting MS that progresses to a phase without relapses with severe gradual decline in functioning.

Question 8

Primary progressive MS

Answer 8

A gradual decline from the onset on. People show more atrophy in the spinal cord and less in the brain. This causes less cognitive impairment than other forms of MS.

Question 9

Clinically isolated syndrome

Answer 9

A single episode with symptoms, can be a preliminary stage for MS.

Question 10

Symptoms of MS

Answer 10

MS often starts with acute visual impairments because of inflammation of the optic nerve. Then other symptoms arise:
- Motor impairments
- Bladder and bowel dyfunction
- Spasm
- Pain
- Sexual dysfunction
- Cogntive impairments
- Fatigue

Question 11

MRI

Answer 11

Active inflammation can be seen with a T1-weighted MRI scan because of the blood that leaks form the opened blood-brain barrier. MS is diagnosed if there is damage to at least 2 locations in the brain or spinal cord and if there are multiple MS-symptom episodes over time.

Question 12

Treatment of MS

Answer 12

Treatment includes medication that focusses on the inhibition of the inflammatory component of the disease and thus prevent the occurrence of relapse. Other drug treatments are counteracts of specific symptoms of MS like: fatigue, sleep problems, numbness of spasms.

Question 13

Cognitive impairments in MS

Answer 13

Cognitive impairment varies form the disease type of MS that people have, for example people with secondary progressive MS have more cognitive impairment than people with relapse-remitting MS.
Cognitive impairment is not as acute as in people with Alzheimer’s, but it slowly progresses throughout the disease. Cognitive decline mostly starts when 75% of the white matter is damaged.
Cognitive symptoms can be problems with:
- Information processing speed
- Learning new things
- Executive functions
- Verbal and visuospatial episodic memory
- Attention
- Verbal fluency
- Social congition
- Also a lot of fatigue, mood problems and pain.

Question 14

Clinical-radiological paradox

Answer 14

Some people have extensive brain damage but perform very well on neuropsychological tests, while other people have limited brain damage but show extensive cognitive impairment.