Demyelinating Disorders - Krafts

Question 1

What are the two most important traits of MS?

Answer 1

1. Characterized by distinct episodes of neurological deficits (separated in time)
2. Due to white matter lesions (separated in space) - can happen anywhere in brain but around the ventricles is common

Question 2

What is MS?

Answer 2

• Most common demyelinating disorder
• Onset usually before 50 (typically diagnosed in 30s, younger person)
• Females >Males, 2:1
• Autoimmune demyelinating disorder
• You get episodes in MS- many different symptoms com and go - after while the patient gets a pattern which the dr can use to determine disease severity

Question 3

What is the pathogenesis of MS?

Answer 3

• Immune system attacking myelin sheath
• Genetic + environmental factor causes
• Linked to HLA-DR2 (3X more likely to get MS); also linked to some IL-2 and IL-7 receptor polymorphisms (many variants)
• Disease probably caused by T cells that react against myeline antigens and secrete cytokines that recruit macrophages to eat myelin
• B cells probably play a role (with depleted B cells, you don’t get as many plaques)

Question 4

What do oligoclonal bands look like in MS?

Answer 4

They are present at the bottom of the band in CSF of MS (and always in blood - even normal)
-The bands indicate a whole bunch of a certain type of antibody is present

Question 5

Where are plaques usually located? What is there prevalence in the brain?

Answer 5

Adjacent to ventricles & LOTS of them

Question 6

What do plaques feel like?

Answer 6

Often firmer than surrounding brain

Question 7

What are the characteristics of active plaques?

Answer 7

• Lipid-stuffed macrophages (chewing up the myelin)
• T cells cuffing vessels
• Axons preserved

Question 8

What are characteristics of inactive plaques?

Answer 8

• No myelin
• Dec. oligodendrocytes
• Gliosis (astrocytes coming in to proliferate and repair after damage - reestablishing neuropil & BBB)
• Most cells around = astrocytes
• Decreased axon number

Question 9

What type of matter are plaques in?

Answer 9

White matter, maybe at junction of white and gray matter or near ventricles (but could possibly occur anywhere)

Question 10

What are hyper intense regions on MRI?

Answer 10

Active plaques!

Question 11

What are central nervous system clinical features of MS?

Answer 11

• UNILATERAL VISUAL IMPAIRMENT (frequent initial manifestation of disease) –> optic nerve involvement
• Cranial nerve signs, ataxia, nystagmus (brainstem involvement)

Question 12

What are spinal manifestations/clinical features of MS?

Answer 12

• Motor/sensory impairment of trunk and limbs
• Spasticity
• Problems with voluntary bladder control

Question 13

What do plaques look like in comparison to white matter?

Answer 13

Sunken in, darker than white matter, more firm

Question 14

What do plaques often follow?

Answer 14

Blood vessels!!

Question 15

What does an MS plaque around a blood vessel look like?

Answer 15

• Oligodendrocytes on outside, lymphocytes on inside

- Cuffing of lymphocytes hanging out around vessels

Question 16

What does MS look like in myelin stain?

Answer 16

Myelin stains deep bluish purple & plaque is lighter pink color.

Question 17

What is this description?

• Diffuse, monophasic, demyelination following viral infection; usually in children
• Rapid onset headache, lethargy, coma
• Fatal in 10%; rest recover completely
• May be an acute autoimmune reaction against myelin

Answer 17

ADEM -Acute Disseminated Encephalomyelitis

Question 18

When do quick onset demyelinating disorders usually occur?

Answer 18

After viral infection or vaccination in kids - within a week or 2, suddenly have symptoms that are nonspecific - headache, lethargic, can lapse into a coma

Question 19

What is this description?

• Fulminant (severe, sudden) CNS demyelination
• Young adults, children
• Preceded by URI
• Fatal in many patients; significant deficits in survivors
• May be hyper acute variant of ADEM

Answer 19

Acute Necrotizing Hemorrhagic Encephalitis

Question 20

What is this description?

• Symmetric loss of myelin in basis pontis and part of pontine tegmentum
• Rapid correction of hyponatremia
• Rapidly evolving quadriplegia
• Monophasic disease (so all lesions are at the same stage of myelin loss) - lesions don’t come and go
• Usually happens after you do something to the patient
• Common in malnutrition, alcoholism, liver transplant, or too little salt (hyponatremia) in blood and you correct it –> then it causes this condition
• If you correct the osmotic gradient in body too fast, you cause this condition
• Starts as flaccid paralysis or other paralysis and then patient may die or get better

Answer 20

Central Pontine Myelinolysis