MS Pathophysiology

Question 1

What type of disease is MS pathophysiologically?

Answer 1

A demyelinating disease of the CNS.

Question 2

What happens to myelin in MS?

Answer 2

It is destroyed by an inflammatory and destructive process.

Question 3

What happens to the axon during demyelination?

Answer 3

It becomes partially or completely denuded (stripped).

Question 4

How does demyelination affect nerve impulse transmission?

Answer 4

It disrupts normal transmission of nerve impulses.

Question 5

What is functional block in MS?

Answer 5

Failure of nerve conduction due to inflammatory activity around CNS venules.

Question 6

Are axons initially preserved in MS?

Answer 6

Yes, initially preserved, though some loss may occur in large chronic plaques.

Question 7

What are the stages of the inflammatory cascade in MS?

Answer 7

Accumulation of inflammatory cells → active destruction of oligodendrocytes and myelin → depletion of oligodendrocytes → scar/plaques formation → partial remyelination (early stages).

Question 8

What inflammatory cells accumulate in MS lesions?

Answer 8

Lymphocytes and monocytes.

Question 9

Which cells actively destroy myelin in MS?

Answer 9

Macrophages and microglia.

Question 10

What happens to oligodendrocytes in MS lesions?

Answer 10

They are destroyed and depleted.

Question 11

What forms as lesions heal?

Answer 11

Scar tissue dependent on astrocytic activity, producing hardened plaques.

Question 12

Can remyelination occur in MS?

Answer 12

Yes, in early stages oligodendroglial progenitor cells can mature and provide partial remyelination.

Question 13

How does remyelination compare to normal myelin?

Answer 13

It has reduced density and quality.

Question 14

What are the most common sites of MS lesions?

Answer 14

Grey-white boundary in the cerebrum, periventricular regions, cerebellar white matter, optic nerves, brainstem, and cervical spinal cord.