multiple sclerosis

Question 1

what is multiple sclerosis?

Answer 1

an autoimmune disease where the myelin sheath on myelinated fibers in the CNS are targeted

Question 2

who are more likely to develop MS and when?

Answer 2

women are 2x more likely and the onset is typically 20-40 years
-caucasians more likely and COLDER regions (lol why)

Question 3

myelinated fibers=

Answer 3

faster travel
unmyelinated= still normal
DEMYELINATED= not normal

Question 4

etiology of MS?

Answer 4

it is unclear but there is STRONG familial tendency (15x more likely to develop)
-genetic susceptibility: MHC/HLA
hla= human leukocyte antigen
hla= gene complex that encodes for the MHC
gla on MHC 1 and 2
hla brings fragments of the virus to the surface of the cell so that the cell can be destroyed, the fragments are presented on MHC1
-viral trigger as well
-environmental factors
-complex trait etiology: multifactoral, polygenic

Question 5

viral trigger for MS?

Answer 5

epstein barr virus—> much like in RF, the infection by EBV can bring on autoimmunity. An IR is triggered but once infection is cleared our defence cells continue to attack and kill self-antigens
in this case the brain

Question 6

pathology of MS?

Answer 6

• demyelinated fibers= slower, AP
• antigens in myelin sheath are targeted by self antibodies
• demyelination occurs in patches (irregular pattern)—> patches (plaques)
• demyelination causes inflammation and damage, resulting in impaired impulse transmission and problems with conduction
• oligodendrocyte necrosis (cells in CNS that produce myelin)
• the location of demyelination varies
• lymphocyte and macrophage infiltration: aka sclerotic patches
• motor AND sensory neurons affected

Question 7

most common locations of demylination

Answer 7

optic nerve, periventricular region, cerebellum, spinal cord, brain stem

Question 8

manifestations of MS?

Answer 8

depends on stage of disease, location of plaques within brain and extent of demyelination

• fatigue, visual impairment, paresthesia (abnormal sensations)
• bowel and bladder dysfunction
• decreased muscle strength
• coordination and gait problems
• chronic exacerbation and remission

Question 9

chronic exacerbation and remission in MS?

Answer 9

very specific to this disease! periods of exacerbation: necrosis of oligodendrocytes and demyelination furthers
-in remission, presence of antibodies decrease and less t cell and macrophage infiltration, short lived usually

Question 10

diagnosis of MS?

Answer 10

• clinical presentation and history of exacerbations and remissions
• MRI: identify areas of demyelination (plaques) their location and extent of damage
• Labs: to exclude other causes of symptoms
• CSF analysis: increased protein content, increased igG Ab d/t targeting self-antigens

Question 11

treatment of MS?

Answer 11

-degenerative disease that often results in acute manifestations following a period of remission
-persistent relapses are treated w/ different drugs
-suppress immune response with steroids and to decrease inflammation
-steroids for relapse (+ interferon)
an interferon is a naturally occuring protein by IS, antiviral agent is not needed here, but the antinflam and immunoregulatory (suppress ab and t cells)

Question 12

what drug is used for MS?

Answer 12

METHOTREXATE

• this is preferred over interferons if possible
• antifolate drug: side effect is inhibition of DNA replication, halting RBC and WBC production–> need folic supplement
• typically give them the prescription, then rest of the week take folic acid
• hepatotoxic (test liver fx)
• CBC
• symptoms (bowel and bladder dysfunction)