Multiple Sclerosis Flashcards
(52 cards)
what is MS
autoimmune inflammatory disorder characterized by demyelination of the CNS
how are plaques distributed in the CNS?
widely throughout the CNS - non-anatomical locations
describe the plaques
well circumscribed, firm, grey lesions
they vary greatly in size and location etc
where is a common location for plaques
cerebral white matter, around lateral ventricles
outline the pathophysiology
- T cells from the periphery enter the CNS through a defective BBB and mount an immune attack on the oligodendrocytes - inflammatory reaction
- this results in demyelination of neurons with relative preservation of axons
- the immune attacks will typically happen in bouts, before the body stops teh attack
- early on in disease the oligodendrocytes heal (=relapsing and remitting features),but over time the oligodendrocytes die and axons beign to be damaged(= chronic disease progression)
how do astrocytes respond to injury
- with reactive astrogliosis - astrocytes undergo changes: cell hypertrophy, proliferation, cell body swell etc
- this forms a glial scar
- which further inhibits remyelination and axonal regeneration - disease further progresses
aetiology of MS
not fully known - combination of genetic and environmental factors
most common age and sex
female, 3rd and 4th decade
geographically, where are you at greater risk
countries further away from the equator (asscoiated with low levels of sunlight and vitamin D)
is there a familial component?
what genes are involved
it is 30x more common in 1st degree relatives
multiple genes, including HLA genes
which specific HLA gene is implicated
HLA DRB1
what role do viruses play in the aetiology of MS, and which virus is it linked to in particular
- viral infections can precipitate MS relapses in someone and can also trigger MS development in a genetically susceptible individual
- EBV
what other environmental factor is MS development linked with?
lack of sunlight exposure and low vitamin D levels
outline the disease course
- highly variable
- Most patients initially present a relapsing-remitting clinical course. Relapses can be induced, e.g. by stress, and early on show complete recovery.
- After 10-15 years of the disease, the pattern becomes progressive with less recovery, during which time clinical symptoms slowly deteriorate.
what is the most common type of MS
RRMS
RRMS
- how do attacks and recovery last
- how many relapses a year
- attacks (relapses) usually occur over a few days and recovery takes a few weeks - partial or complete
- usually pts have around 1 relapse a year
- if relapses dont recover fully, disability can accumulate over time
benign MS
in RRMS, patients go without relapses for a few years - benign MS
compare the pathological ativity of RRMS and PPMS
RRMS shows the most inflammatory activity. PPMS is thought to be a primarily degenerative process and shows less inflammation
2y progressive MS
75% of RRMS patients will develop this around 35 years after disease onset - damage is not recovered from fully and disability accumulates
PPMS
this is a less common type, a primarily progressive disease, gradually worsening of disability without any relapse or regression
this tends to present later in life
what are some poor prognostic signs
older age, motor signs at onset, many relapses early on, lots of MRI lesions, axonal loss
outline the criteria for diagnosis
- At least 2 episodes suggestive of demyelination, there must be dissemination in time and place (attack >1hr, >30days between)
- Unattributable to other cause
when is the McDonald criteria used
mainly for research purposes, rarely in clinical practice
what is the classical presentation
temporary visual loss/optic neuritis or sensory symptoms
presentation is often monosymptomatic
