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Cumulative > Multiple Sclerosis & Myasthenia Gravis > Flashcards

Multiple Sclerosis & Myasthenia Gravis Flashcards

1
Q

Define MS

A

chronic autoimmune disease involving inflammation and destruction of CNS white matter by demyelinating nerve sheaths

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2
Q

What is the epidemiology of MS

A
  • most common demyelinating disease of the CNS
  • onset 20-50 with peak at 40s
  • 30 year life expectancy
  • RF: living far from the equator (low vit D, northern euro descent), W>M, link to EBV
  • 5% familial recurrence (hereditary predisposition)
  • more likely to have other comorbid autoimmune disorders
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3
Q

Describe the pathophysiology of MS

A
  • autoimmune/inflammatory insult to myelin sheath (B cells)
  • inflammatory plaques created disrupting integrity of BBB
  • leukocytes enter CNS and cause inflammation cascade (T cells)
  • destruction of myelin and gradual neurocognitive decline (macrophages)
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4
Q

What are current therapies for MS focused on

A

inhibiting T cell and B cell function that takes part in the pathophysiology of MS

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5
Q

What happens to nerve conduction in MS

A
  • nerve impuse unable to traverse the demyelinated portion of an axon efficiently causing it to be slower
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6
Q

Define sclerosis in MS

A
  • pathologic appearance at autopsy
  • hard rubbery areas in white matter of brain and spinal cord
  • can be any white matter but commonly the periventricular, corpus callosum, optic nerves, dorsal spinal cord
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7
Q

Describe the clinical manifestations of MS

A

-MC is fatigue
- sensory disturbance
- ataxia
- bladder problems
- visual loss
- spasticity
- gait problems
- Uthoff phenomenon (heat intolerance)
- paresthesia/tingling
- cerebral deficits
- paroxysmal symptoms

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8
Q

What is the most common presenting manifestation of MS

A

Sensory Symptoms
- paresthesia or hypoesthesia
- starting in one leg and spreading to the other then ascends to pelvis, abdomen, thorax
(characteristic of spinal cord involvement)

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9
Q

What is the second most common manifestation of MS

A

Motor Symptoms
- limb weakness
- spasticity
- gait disturbance

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10
Q

Describe optic neuritis in MS

A
  • loss of vision evolving over hours/days
  • 3rd most common manifestation
  • Scotoma; area of blurred vision
  • color distinguishing is difficult
  • periorbital pain
  • diplopia
  • demyelinating optic nerve
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11
Q

Describe bilateral internuclear ophthalmoplegia in MS

A
  • failure of eye ADDuction with nystagmus in ABduction
  • most common eye movement disorder in MS
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12
Q

Describe the ataxic gait seen in MS

A
  • propulsion
  • incoordination
  • spasticity
  • slapping feet down
  • hyperextending knees
  • shifting weight to slow body down
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13
Q

Describe the autonomic deficits seen in MS

A
  • urinary difficulties caused by upper motor injury of spinal cord
  • susceptible to UTI which can trigger MS flares (immune system stimulated)
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14
Q

Describe the cerebral deficits seen in MS

A
  • memory loss
  • personality change
  • emotional lability
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15
Q

Describe some of the commonly seen paroxysmal symptoms in MS

A

Indicative of a relapsing component
- twitching or muscle spasm
- difficulty swallowing
- word finding problems
- shooting pain
- tics of eyelids or lips
- facial or tooth pain

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16
Q

Describe the Uhthoff Phenomenon

A

temporary worsening of MS syx caused by increased temperature
- usually worsening visual symptoms
- fatigue, pain, balance, weakness, etc

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17
Q

Describe Lhermittes Phenomenon in MS

A

Sudden brief pain or electrical buzzing sensation, down neck into spine, may spread into arms/legs
- triggers: bending neck forward, coughing, sneezing, etc
- indicates pathology in C-spine

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18
Q

Describe the difference between primary, secondary, and tertiary symptoms of MS

A

Primary: plaque/axonal damage corresponding to a location in the CNS
Secondary: subsequent conditions from primary plaques
Tertiary: psychosocial effects

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19
Q

Describe the physical exam for MS

A
  • do complete neuro exam
  • may see hemi/monoparesis
  • ocular abnormalities (blurred, double)
  • hyperreflexive +/- clonus
  • genital anesthesia
  • loss of position/vibration sense
  • ataxic gait
  • spasticity (LE>UE)
  • positive babinski
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20
Q

What are the 4 types of MS

A
  • Clinically isolated syndrome
  • relapsing remitting disease
  • secondary progressive disease
  • primary progressive disease
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21
Q

Describe CIS MS

A

Clinically Isolated Syndrome
- first episode of neuro syx lasting at least 24hrs
- caused by inflammation or demyelination
- monofocal (single s/s caused by single lesion) or multifocal (multiple s/s caused by lesions in multiple places)

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22
Q

Describe the risk of progression in CIS

A
  • high risk when MRI detects brain lesions
  • low risk otherwise
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23
Q

Describe the Macdonald Criteria for diagnosing MS

A
  • evidence of damage in 2+ separate areas of the CNS including the brain, spinal cord optic nerves
    AND
    -evidence that the damage occurred at different times
    AND
    -rule out all other diagnoses
24
Q

Describe imaging for MS

A

MRI most useful
- gadolinium enhancing lesions can be found in early stages
- sensitive but not specific
- image brain and entire spinal cord (plaques usually dorsal)

25
Q

What does this show

A

T1 weighted MRI of brain of someone with MS

26
Q

Describe

A

MS lesions seen in each view
image D shows gadolinium enhancing lesion under T1 weighted image with Gd

27
Q

Describe

A

MS lesions of the spinal cord

28
Q

Describe the lumbar puncture findings consistent with MS

A
  • elevated total IgG and IgG ratio
  • oligoclonal bands
  • proteins indicative of myelin breakdown (oligoproteins)
29
Q

Describe the 2 major themes of MRI criteria for MS

A

Dissemination in space (3+)
- one or more T2 lesions in 2 of 4 CNS areas: pariventricular, cortical, infratentorial, spinal cord

Dissemination in time
- Gd enhancing and non Gd at any time
- detectino of new T2 lesion or Gd inhancing lesion compared to baseline scan

30
Q

Describe evoked potential testing (EEG or EMG) in MS

A
  • measures CNS electric potentials by repetitive stimulation of specific nerves
  • looking for delays in potential and conduction blocks
  • tests visual pathways and spinal cord dorsal columns
31
Q

What labs would be helpful in ruling out other disorders in diagnosing MS

A
  • CMP
  • lyme titer
  • Vit B12
  • ANA
  • ESR
  • HIV ab
  • syphilis
32
Q

Describe Relapsing Remitting MS (RRMS)

A

most common type
- attacks/relapses followed by complete remission
- can last months to years without new syx
- new episodes are erratic

33
Q

Describe Secondary Progressive MS (SPMS)

A

likely the 2nd stage of RRMS
- distinct exacerbations with no remission
- progressive neuro deterioration
- brain atrophy increases
- progression from RRMS to SPMS = 19 years
- men and older pts progress faster

34
Q

Describe primary progressive MS (PPMS)

A

least common
- disease progressive from onset with no relapse or remission
- usually later in life
- associated with major spinal cord involvement
- usually present with leg weakness/gait disturbance

35
Q

What are the factors negatively influencing prognosis

A
  • male gender
  • high rate of relapse
  • incomplete recovery from first attack
  • short remission interval
  • symptoms of efferent systems
  • older age of onset
  • significant disability at 2 and 5 years from onset
  • early cerebellar involvement
  • involvement of more than one CNS system at time of onset
36
Q

Describe disease modifying therapy in MS

A
  • immunomodulators ($$$): interferons (Rebiv, Avonex, Plegridy)
    - CI in pregnancy and lacttaion
    - AEs: elevated LFT, leukopenia, thyroid disease, myalgia, flu-like sx, depression, GI, injection site rxn
  • off label therapies
37
Q

Describe the management of MS

A

Goal is to slow progression and improve QOL, treat exacerbations
- MRI monitoring ever 3 mos after suspicious episode
- corticosteroid therapy to shorten relapse and accelerate recover (prednisone)
- disease modifying therapy started early to minimize axonal damage (anti-CD20 Ab - Ocrevus, Pyrimidine synthesis inhibitor - teriflunomide, Fumarates - Tecfidera)

38
Q

What are some off-label therapies for MS

A
  • broad spectrum immunosuppressants (cyclophosphamide)
  • IVIg
  • plasma exchange
39
Q

Describe the MS relapse protocol

A

Mild: nonpharm support
Moderate: PO steroids vs 1 IV dose with taper
Severe: hospital, IV methylprednisolone, +/- plasma exchange

40
Q

Describe the non-pharm treatment of MS

A

Multidisciplinary
- PT/OT/SLP
- rehab
- psychotheraphy
- complementary/alternative therpies for lifestyle

41
Q

Describe the symptomatic pharm treatment of MS

A

-Spasticity: baclofen, tizanidine
-Fatigue: Modafinil
-Neuropathic pain: gabapentin, ASMs
-Bladder: anticholinergic

42
Q

Describe the Kurtzke Expanded Disability Status Score

A

Measures the neuro impairment in MS

43
Q

What may be on your differential list when evaluating for MS

A

Demyelinating diseases
- guillain barre
Chronic infection
- lyme
- syphilis
- HIV
Psych
Vascular disease
- stroke
- AVM
- vasculitis
Autoimmune
- SLE
- Sjogrens
- Sarcoidosis
Malignancy

44
Q

Define Myasthenia Gravis

A

Most common neuromuscular junction disorder
- primary disease of neuromuscular transmission
- weakness d/t autoantibodies against acetylcholine receptors
- usually detected after viral infection

45
Q

Describe the epidemiology and risk factors of myasthenia gravis

A
  • risk factors: FH 5%, autoimmune disorders, D-penicillamine use in Wilson’s dz, thyroid disorders
  • F>M
  • onset in F = teens, 20s
  • onset in M = 40-50s
46
Q

Describe the pathophys of MG

A
  • autoantibodies target ACh receptors at NMJ, damage to postsynaptic membrane
  • detected after viral infx: measles, EBV, HIV
  • small amount associated with thymus dysfunction and T-cell mediated autoantibody production
47
Q

Describe the clinical presentation of MG

A
  • bilat ocular motor weakness, ptosis, diplopia are the most common initial symptoms
  • bulbar symptoms
  • generalized muscle weakness in proximal limbs more than legs, trunk, respiratory
    - fatigue (hallmark)
  • onset can be sudden and severe or mild/intermittent over years
48
Q

Describe a myasthenic crisis

A

-respiratory muscle weakness producing insufficiency and impending resp failure
- severe bulbar symptoms
- may require mechanical vent
- can be triggered by infection/aspiration, pregnancy, postpartum

49
Q

Describe the physical exam in MG

A
  • ptosis may worsen with propping of opposite eye or sustained upward gaze (curtain phenomenon)
  • snarling expression
  • symmetric muscle weakness in proximal limbs (sustained abduction of arms, repeated rising from chair without arms)
  • monitor resp function
  • Tensilon test
  • Ice pack test: 2 mins of icing muscle may improve weakness
50
Q

Describe the tensilon test used in MG examination

A

Tensilon (edrophonium) is an acetylcholinesterase inhibitor that is given IV to the pt before they perform muscle movements.

Test is positive if pts strength improves

Less common d/t worsening of syx and cholinergic side effects, and requires cardiac monitoring!

51
Q

Describe the labs involved in MG examination

A

-antiacetylcholine receptor antibody blood test: positive in 90% of pts with generalized MG and 50% in ocular MG
- antimuscle specific tyrosine kinase antibody
- other antibody testing

52
Q

Describe some of the electrodiagnostic studies for MG

A
  • slow repetitive nerve stim: measure action potential of muscle: shows decrease in action potential with first 5 stimuli
  • single fiber EMG: variable transmission time called a jitter
53
Q

What is the hallmark symptom of MG

A
  • fatiguability of muscles
  • the more the muscle is used the weaker it will get
54
Q

What might be on the differential list when evaluating MG

A
  • thyroid ophthalmopathy
  • oculopharyngeal muscular dystrophy
  • brain stem and motor nerve lesions
  • botulism
  • ALS
  • drug induced MG
55
Q

Describe the management of MG

A

Multidisciplinary team
- pharm: cholinesterase inhibitors (Mestinon or Prostigmin), corticosteroids for immunosuppression, IVIg for crisis
- respiratory monitoring
- thickened liquid diet
- avoid meds that can make MG worse: abx, beta blockers, Ca channel blockers, iodine contrast, Li, D-penicillamine (Wilson’s)

56
Q

Does MG typically present with sensory loss or pain

A

Nope

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