MS Flashcards
what kind of disease is MS
Autoimmune demyelinating disorder affecting the CNS
what is Charcot’s triad of MS
Nystagmus, intention tremor and scanning speech
who is mostly likely to get MS
females 20-50 y/o of northern european descent
risks seem to increase with distance from the equator
what are the suspected environmental triggers for MS
viral exposure (EBV, canine distemper virus)
tobacco exposure
lack of exposure to infectious agents early in life
what viruses are possibly protective against MS
CMV, HSV, HIV
what is the pathogenesis of MS thought to be
ACP present a signal and active T-cells in the lymph node.
Activated T-cells enter the peripheral blood stream to find their target in the CNS.
T-cells attach to, break down and cross the BBB.
secrete pro-inflammatory cytokines leading to myelin destruction and neuronal death
how do the T-cells enter the CNS
release of IL’s that cause an inflammatory response to disrupt the BBB
describe the effects of MS on the axons
demyelination leads to garbled signals being sent via the nerves - over time the myelin may regenerate or axonal damage may occur
what is the clinical characteristics of MS
clinical relapses with new neurological symptoms lasting > 24 hours due to CNS demyelination followed by remission
usually 1-2 attacks per year
what is optic neuritis
decreased monocular vision (often involving central vision)
pain with eye movement
decreased red/green color
what other ocular problem is optic neuritis associated with
Afferent pupillary defect (APD or Marcus-Gunn pupil)
what is the Uhthoff phenomeon
optic neuritis in MS gets worse with heat - used to test by having the pt sit in a hot tube
how is an afferent pupillary defect tested
shine a light in the affected eye and neither eye constricts but shine a light in the other eye and both will constrict
how do lesion in MS differ from a stroke
stokes usually affect deep areas of the brain first (where there is less blood supply)
MS lesions tend to be near the periphery of structures where there is greater blood supply
what are 6 brainstem syndromes that are highly suggestive of MS
Internuclear ophthalmoplegia Oculomotor dysfunction Ataxia Trigeminal Neuralgia Facial nerve palsy CST/upper motor neuron involvement
what is Internuclear ophthalmoplegia and where is the lesion likely
when one eye is unable to adduct when looking laterally but is able to accommodate for close objects
likely a lesion near the CN 6 nucleus
what is Lhermitte’s sign
electric shock sensation with the neck flexed
what does a sensory level indicate
spinal cord lesion
what are some symptoms that can help distinguish MS from GBS
sensory level
urinary urgency, incontinence, ED
what does a Romberg sign indicated
loss of proprioceptive control (does not localize to the central or peripheral NS)
how is MS diagnosed
- objective demonstration of a CNS white matter lesion based on clinical or radiographic grounds that are separated in time and space (and there is no other better diagnosis)
what are the typical locations for a MS lesion
Juxtacortical, periventricular, infratentorial, spinal cord
what are some characteristics of a typical MS lesion
Lesions >3mm
Corpus callosum lesions
Optic radiation lesions
Brainstem lesion abutting the 4th ventricle or aqueduct
Incomplete/partial enhancement
T1 “Black Holes”- atrophy from chronic damge
describe Dawson’s fingers
perpendicular oriented periventricular lesions - seen in a saggital flair scan - only seen in MS
where are spinal cord lesions usually located in MS
Located in the cord periphery, especially the dorsal columns
- Lesions begin at the pial surface
how big are the spinal cord lesions typically
small
what is another test you could do for MS if the MRI is not clear
Lumbar puncture and look at the CSF
what would the CSF show in MS
normal protein, glucose, and cells counts usually
w/ Oligioclonal bands and possibly IgG abnormalities (elevated intrathecal IgG synthesis)
what do oligioclonal bands in the CSF indicate
- Provides evidence for intrathecal synthesis and carries the implication of immunological process in the CNS
- Once present are persistent
- OCBs with optic neuritis or first event (CIS) is associated with an increased risk of MS
what are 3 other disease processes that should be on your differential when considering MS (classic MS mimics)
Neuromyelitis Optic and acute disseminated encephalomyelitis
what is neuromyelitis optica
- Longitudinally extensive spinal cord lesion (>3 vertebral segments)
- Bilateral optic neuritis
- Hic-coughs
- Normal/minimal brain lesions
- NMO IgG Ab positive (also autoimmune but with Ab for a aquaporin)
what is acute disseminated encephalomyelitis (ADEM)
- Often post-infectious process
- Commonly present w/ HA, vomiting, drowsiness and meningism (often initially treated for infectious meningoencephalitis)
- Large, “fluffy” multifocal lesions
- More common in children than adults
- one time occurance
what is PML caused by
John Cunningham Virus (opportunistic infection)
who commonly gets PML
- people with HIV
- can also be a rare side effect that occurs in those taking natalizumab (MS drug) who are also JC virus positive
whats the prognosis of PML
Can lead to death or severe neurologic injury; better chance of recovery with early detection
what are the lesion like in PML
Multiple lesions are commonly present
Frequently subcortical hemispheric white matter or cerebellar peduncles
how should you treat a patient with an MS relapse
IV methylprednisonle
