Final exam - Multiple Sclerosis

Question 1

Causes & Risk Factors of MS

Answer 1

• Multifactorial with no one cause appearing to be sufficient on its own for the development of MS
  1. Genetic Predisposition : 1.1. Influences disease susceptibility and clinical outcome (monozygotic twins around 30% highlights importance of non-genetic factors, dizygotic twins/sinblings/parents 2-5% still higher than general pop.)
  1.2. Focused on human leukocyte antigen (HLA) gene complex (plays a role in regulation of immune system, some regions containing genes thought to be responsible for MS overlap with gene areas for other autoimmune disease)
  2. Geographic Latitude (likely related to Vitamin D exposure) :
  2.1. Those closer to the equator have a lower risk (i.e. more vitamin D)
  2.2. Sunlight may also contribute to immune system function through alterations in other bodily chemicals (Vitamin A and daily melatonin levels)
  3. Infections (infectious agents may initiate or maintain the pathological immune response in MS) :
  3.1. Those with MS contract more childhood illnesses, and more illnesses later
  3.2. Evidence of elevated levels of CSF antibodies to several viruses (particularly, Epstein-Barr virus)
  3.3. MS exacerbations often triggered concurrently with bacterial or viral infections

Question 2

Causes & Risk Factors of MS - Part 2

Answer 2

4. Hormones/Pregnancy/Menstrual Cycle : Inflammation, relapse rates, and MS lesion activity typically decline during pregnancy
5. Gut Microbiome : Significant differences between the gut bacteria of people with MS vs. those without (more bacteria associated with inflammation in MS)
6. The usual : smoking (increased risk, also makes symptoms worse), alcohol abuse, diabetes (or other autoimmune disease as thyroid disease)

Question 3

Disease Course

Answer 3

• The course of the disease is variable and initially difficult to predict
• Consensus definitions for 4 disease courses :
  Relapsing-remitting MS (RRMS), Primary-progressive MS (PPMS), Secondary-progressive MS (SPMS), Progressive-relapsing MS (PRMS)

Question 4

Relapsing-remitting MS (RRMS)

Answer 4

• 80-85% : relapse and remission that repeat overtime
• Acute episodes of neurological deterioration with variable recovery but stable course between attacks
• Refers to clearly defined disease relapses with full recovery or with residual deficits upon recovery
• The periods between relapses are characterized by a lack of disease progression

Question 5

Primary-progressive MS (PPMS)

Answer 5

• 10-15% : first symptom disease gets worse as it progresses, as they go on with life it gets worse
• Refers to steady disease progression from symptom onset with possible occasional plateaus and possible minor improvements
• Gradual, nearly continuous worsening of neurological function with, typically, no discrete relapses

Question 6

Secondary-progressive MS (SPMS)

Answer 6

-60-65% of those initially diagnosed with RRMS will progress to SPMS : never at first diagnosis, relapse and remission and then switch to just primary progressive, no remission
- An initial RRMS presentation followed by a phase of progressive deterioration, with or without occasional relapses, or minor plateaus
- Viewed as the inevitable long-term outcome for the majority of RRMS patients
- Switch from one course to the other is indicated roughly by when time between relapses becomes worse : around 10-20 years, men seem faster than women, it’s really a look back and notice situation

Question 7

Progressive-relapsing MS (PRMS)

Answer 7

• Rare, probably call this active PPMS : period between relapses keeps getting worse, very progressive, demyelination is way worse
• Refers to progressive disease from symptom onset with clear, acute relapses, with or without full recovery
• The periods between relapses are marked by continuing disease progression

Question 8

Cognitive Impairment

Answer 8

• Prevalence rates for cognitive impairment in MS range from 43-70% (degree of impairment linked to total brain volume affected by lesions, as well as total brain atrophy, can present in individuals even with minimal physical disability)
• Most patients will have cognitive changes measurable by neuropsychological tests
• 5-10% have cognitive changes so severe that they seriously disrupt daily life (managing finances, ability to perform self-care activities)
• Various domains can be affected : Attention, Information Processing Speed (IPS), Verbal/Visual Memory, Language

Question 9

Information Processing Speed

Answer 9

• Biggest bang for your buck
• Relative Consequence Model : deficits in information processing speed underlie deficits observed in all other cognitive domains, impairments in variety of cognitive processes are simply a by-product of slowed IPS