With Complete Solutions
What type of hypersensitivity is Multiple Sclerosis?
TYPE 4 HYPERSENSITIVITY CHRONIC, CELL
MEDIATED AUTOIMMUNE DISORDER
àDEMYELINATION OF THE CNS.
What is the underlying pathology of MS?
,Inflammation, demyelination, and eventual axonal
degeneration
There are plaques of demyelination and scarring aka sclerosis
along neurons
This slows or blocks the transmission of signals to and from the
brain and spinal cord. In this way movement and sensation may
be impaired.
Describe the epidemiology of MS
- 3 times more common in women
- Most common diagnosed in 20-40 years old
- Much more common at higher latitudes –eg is 5 times more
common in tropics
Environmental triggers for Multiple Sclerosis
UV radiation
Insufficient vitamin D consumption
Cigarette smoking
VIRUSES: EBV, HHV 6
Explain how MS is a type IV hypersensitivity reaction
CD4 MEDIATED DESTRUCTION OF
OLIGODENDORIAL CELLS AND THEN A HUMORAL
, RESPONSE WHICH IS WHAT CAUSES INFLAMMATION -
acute inflammatory demyelination
Remember that because it is cell mediated, it releases cytokines
such as IL-1,IL-6 which dilates blood vessels of the BBB
allowing more cells to get in
Once the inflammation is finished, there is some healing
where plaques are created around the damaged axons
INFLAMMATORY DEMYELINATION - PLAQUES
Outline the different types of MS
Relapsing-remitting MS: MOST COMMON, symptoms come
and go. Periods of good health or remission are followed by
sudden symptoms or relapses (80% of people at onset).
Secondary progressive MS: follows on from relapsing-
remitting MS. There are gradually more or worsening symptoms
with fewer remissions (about 50% of those with relapsing-
remitting MS develop secondary progressive MS during the first
ten years of their illness)
.
Primary progressive MS: from the beginning, symptoms
gradually develop and worsen over time (10-15% of people at
onset).