Multiple sclerosis Flashcards
(40 cards)
define MS
Chronic autoimmune T cell mediated inflammatory disorder of the CNS
diagnosis requires two or more attacks affecting different parts of the CNS = dissemination in time and space
what is the commonest cause of chronic non-traumaticneurological disability in young adults?
multiple sclerosis
at what age does MS usually begin?
20-40 years
what is primary progressive MS?
slow, unstoppable decline in neurological function from the outset of the disease
what is secondary chronic progressive MS?
slow unstoppable decline in neurological function following a relapsing remitting course
what three major factors influence whether someone gets MS?
genetics
environment
chance
what is the geographical distribution of MS?
closer to the equator, MS is less common
which ethnic origin is most likely to get MS?
white/Caucasian
is MS more common in males or females?
females
what is the link between MS and migration?
if a sb migrates from a country where MS is not prevalent to one where it is common, their risk of developing MS increases and this is affected by the age of migration (in this case an earlier migration to a country where MS is common will increase the risk)
what is the concordance of MS in monozygotic twins and what does this mean?
30%
this figure is lower (~ 5%) in dizygotic twins so there is some genetic influence but not purely genetic as it is not 100%
so need to be genetically susceptible
what components of the immune system are relevant to MS?
T cells B cells and the antibodies they make macrophages complement cytokines
Explain the pathology of MS
may be triggered by a viral infection, lymphocytes become able to enter the BBB (not normal) and evoke an immune response there - macrophages and antibodies can cause demyelination and damage to axons. Remyelination may occur, but the myelin is thin and axonal damage does not recover
plaques of demyelination form and these can be seen microscopically and on MRI
PNS not affected
what are the features of active lesions in MS?
demyelination hypercellular plaque edge due to inflammatory infiltration perivenous inflammatory infiltrates extensive BBB disruption older plaques have central gliosis
what are the features of inactive lesions of MS?
demyelination
hypocellular plaque
moderate to minor BBB disruption
plaques are gliosed
what symptoms and signs do spinal cord plaques cause?
weakness, paraplegia, spasticity, tingling, numbness
Lhermitte’s sign
bladder and sexual dysfunction
what symptoms do affected optic nerves produce?
optic neuritis
eye pain
impaired vision
what symptoms and signs does damage to the brainstem cause?
dysarthia
double vision
vertigo
nystagmus
what symptoms and signs does damage to the cerebellum cause?
dysarthia nystagmus intention tremor ataxia think DANISH
which parts of the CNS are mainly affected by MS?
optic nerves periventricular region corpus callosum brainstem cerebellum spinal cord - corticospinal tracts and DCML
what are the typical symptoms and signs in MS?
optic neuritis spasticity pyramydal signs (ie those of a UMN like hyperreflexia, Babinski sign) sensory symptoms and signs - reduced vibration and proprioception Lhermitte's sign hystagmus double vision vertigo bladder and sexual dysfunction tiredness depression loss of coordination Uhthoff’s phenomenon
what is Lhermitte’s sign?
electric shock-like sensation that occurs on flexion of the neck. This sensation radiates down the spine, often into the legs, arms, and sometimes to the trunk
tremor
ataxia
what is Uhthoff’s phenomenon?
temporary worsening of symptoms with increases in body temperature eg after exercise or hot bath
what are the common first symptoms of MS?
weakness paraesthesiae visual loss incoordination vertigo sphincter imparment
