6 - Clinical Diagnosis of MS Flashcards
what is MS?
inflammation of the CNS following the infiltration of immune cells across the BBB
what does MS do to neurons in the CNS?
demyelinates the neurons
what nerves does MS affect?
CNS
not periphery
what is the epidemiology of MS?
- women:men = 3:1
- age of onset = 20-30 years
- prevalence 1:500
describe the pathophysiology of MS:
- T cells are activated which activates proteins that breakdown the BBB
- APC then binds to Tcells, further activating them, and releasing chemokines
- causes an influx of more immune cells
- results in abtibodies attacking the myelin sheath of the neuron
what are the 2 roles of myelin?
- propogates signals across neurons - jumps from node of Ranviers
- protects axons - without myelin, axons become truncated and neuronal loss occurs
how does demyelination effect a neuron?
- delays or blocks impulse
why might permanent disability occur in MS?
nerve may be sectioned or die due to demyelination
what are 3 broad manifestations of MS?
- optic neuritis
- brainstem symptoms
- spinal cord symptoms
what is optic neuritis?
- inflammation of optic nerve
- results in pain on eye movement, blurring of vision, red colour saturation
Uhthoff’s phenomenon
- transient worsening of neurological symptoms related to a demyelinating disorder such as multiple sclerosis when the body becomes overheated in hot weather, exercise, fever, saunas, or hot tubs
- irritates scar tissue in optic nerve
occurs in pts who have previously had optic neuritis
what brainstem symptoms can be associated with MS?
- vertigo
- slurred speech
- ataxia
- incoordination
- double vision
what spinal cord symptoms can be associated with MS?
- sensory - Lhermitte’s phenomenon
- motor - upper and/or lower limb weakness
- bladder, bowel, sexual dysfunction
what is Lhermitte’s phenomenon?
flexion of the neck causes “electric shock” sensation down neck + parastesia
what is radiologically isolated syndrome?
- pts have typical MS signs on scans, eg. demyelination and lesions
- but do not have clinical symptoms
- therefore, no MS diagnossi
what is clinically isolated syndrome?
- pts have damage seen on scans that is typical of MS
- also have a one off occasion of MS symptoms
draw a diagram showing the difference between upper and motor neurone signs for:
* muscle bulk
* fasciculations
* tone
* power
* reflexes
* clonus
* babinski’s sign
what are fasciculations?
muscle twitching that occurs when a single peripheral nerve is overactive
what would be a positive clonus sign?
- examiner feels and sees the oscillations of the foor against pressure
- 3 or more is abnormal
what is a positive babinski sign?
flexion of big toe and fanning of other toes
in what pt group is a positive babinski sign normal?
- newborns and infants
- should be absent after 24 months
MS characteristically has which of the following - UMN signs or LMN signs?
upper motor neuron
what are 3 main investigations for MS diagnosis?
- MRI
- lumbar puncture
- evoked potentials (usually visual)
what are 5 common sites of demyelination is MS?
- corpus callosum
- optic nerve
- cerebellum
- brainstem
- spinal cord
what are oligoclonal bands?
immunoglobulins
what does the presence of oligoclonal band in CSF indicate?
- inflammation of CNS
- can indicate MS diagnosis
what findings in CSF may indicate MS?
oligoclonal bands type 2
what are visual evoked potentials?
- tests optic nerve pathway from eyes to visual cortex
- electrical signals recorded through the scalp
what finding on a visual evoked potential may indicate MS?
- delayed VEP
- demyelination in anterior visual pathways
what two evoked potentials can be used in MS diagnosis?
- visual evoked potentials
- somatosensory evoked potentials
what do somatosensory evoked potentials assess?
- posterior column of spinal cord, brainstem and cerebral cortex
what are the main criteria for MS diagnosis?
two different relapses (space) at two different times
dissemination in space - what does this mean in MS diagnosis?
must be a development of lesions in two or more distinct anatomical locations in CNS
* brainstem
* juxtacortical
* periventricular
* spinal cord
dissemination in time - what does this mean in MS diagnosis?
development or appearance of new CNS lesions over time
OR
positive oligoclonal bands
what factors can indicate better prognosis in early MS?
- caucasion
- female
- monofocal onset
- onset with optic neuritis or isolated symptoms
- low relapse in first 5 years
- long interval to second relapse
if MS pts have onset symptoms with motor, cerebellar or bladder or bowel symptoms, would this indicate a better or poorer prognosis?
poorer
what is the inheritance risk of MS for someone with a first degree relative?
1:25
the majority of MS pts have what type of MS?
relapsing-remitting (85-90%)
what is relapsing-remitting MS?
- attacks with complete or partial recovery (still neuronal damage)
- no progression between attacks (remission)
what is secondary progressive MS?
- initial relapsing-remitting course followed by progression (without active disease but due to neuronal degeneration)
- with or without attacks
what is primary progressive MS?
- steady progression from onset
- no attacks or remission
what is progressing-relapsing MS?
progression from onset with attacks
are pts always aware of MS relapses?
no - can only be aware 10-15 years later when neuronal degeneration is significant
how are MS relapses treated?
- high doses of corticosteroids (orally or IV)
- reduce inflammatory activity and stabilise blood brain barrier
what is natalizumab or tysabri?
- disease modigying therapy (DMT)
- binds to T cells and stops them degrading myelin sheath
when can pts take tysabri for MS?
- relapsing MS
- at least two relapses in last year
- MRI shows new signs that MS is active
