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BMB Test 2 > B7.024 Bell's Palsy > Flashcards

B7.024 Bell's Palsy Flashcards

1
Q

corticobulbar tract

A

supplies all UMN innervation to the cranial nerves

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2
Q

upper face innervation

A

bilateral

both hemispheres

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3
Q

lower face innervation

A

contralateral hemisphere

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4
Q

central facial weakness

A

only lower facial weakness

UMN type lesion (bc upper face still receives innervation from ipsilateral brain)

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5
Q

peripheral facial weakness

A

entire hemisphere is weak (upper and lower face)

LMN type lesion

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6
Q

where would a peripheral facial weakness lesion localize

A

between brainstem and muscles

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7
Q

2 classes of peripheral facial weakness lesions

A 
intra-axial = inside brainstem
extra-axial = outside brainstem
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8
Q

hallmark of a brainstem lesion

A

“alternating hemiplegia”
if nuclei within the brainstem are damaged, the corticospinal system which also runs through the brainstem would be damaged as well
would see body weakness on the opposite side of facial weakness

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9
Q

pattern of deficits for brainstem lesions

A

ipsilateral CN

contralateral long tracts (weakness, numbness)

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10
Q

how to rule out intra-axial lesions

A

no long tract symptoms / signs

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11
Q

where does the facial nerve exit the brainstem

A

pons

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12
Q

4 nuclei of the facial nerve

A

facial motor nucleus
gustatory nucleus
main sensory nucleus
superior salivatory nucleus

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13
Q

functions of the facial nerve

A

facial muscle movement
taste on anterior 2/3 of tongue
ear region sensation
parasympathetic salivation / lacrimation

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14
Q

facial motor nucleus innervation

A

face muscles
stapedius
digastric

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15
Q

gustatory nucleus innervation

A

taste on anterior 2/3 of tongue

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16
Q

main sensory nucleus innervation

A

ear region sensation

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17
Q

superior salivatory nucleus innervation

A

lacrimal, submandibular, sublingual glands

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18
Q

patterns of facial nerve deficits

A

facial weakness
hyperacusis
decreased taste
dry eyes

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19
Q

why is it important to understand the basic course of the facial nerve

A

branch points help to localize the site of the lesions

20
Q

geniculate ganglion

A

contains nerve cell bodies of all sensory nerve branches of the facial nerve

21
Q

important of a lesion located after the stylomastoid foramen

A

increases likelihood of a malignant parotid tumor

higher up lesions are usually benign

22
Q

list the relevant branch points of facial nerve proximally to distally

A

geniculate ganglion

  • greater petrosal nerve to pterygopalatine ganglion (lacrimal gland)
  • nerve to stapedius (hearing)
  • chorda tympani (taste, salivatory glands)
  • *stylomastoid foramen**
  • facial motor branches
23
Q

how is taste sensation tested

A

table salt and table sugar

24
Q

what might you see on an MRI in bell’s palsy

A

increased signal intensity in the internal auditory canal

nerve / blood barrier broken down

25
Q

what is Bell’s palsy

A

idiopathic

peripheral CN 7 palsy

26
Q

Bell’s palsy pathology

A 
based on autopsy specimens and clinical observations at surgery (doesn't kill people)
intraneural inflammation (+/- segmental demyelination)
swelling and compression within the Fallopian canal and the perineurium (+/- axon loss)
27
Q

suspected relationship between HSV1 and Bell’s palsy

A

can be isolated from nasopharynx of people with Bell’s
HSV antibody titer rises
virus isolated from epineurium of biopsy specimen
PCR positive for HSV in endoneurial fluid of Bell’s patients
saliva positive for HSV by PCR in 11/38 Bell’s patients and 0/10 normal controls

28
Q

components of natural history of Bell’s palsy

A 
proportion complete recovery
time to recovery
complications
-aberrant re-innervation
-hemi-facial spasm
29
Q

outcomes by which degree of recovery from Bell’s palsy is measured

A 
primary motor function
-symmetry at rest
-forehead
-eye closure
-mouth
secondary defects
-synkinesis
-gustatory tears
-facial spasm
30
Q

synkinesis

A

aberrant reinnervation
due to Wallerian degeneration in some axons leading to nerve regeneration
if connective tissue is damaged, nerve can regenerate to the wrong place

31
Q

examples of synkinesis

A

people wink when they try to smile

tear up when smiling

32
Q

house and brackmann grading scale

A

1 = normal
6 = total paralysis
lower number is better in recovery from Bell’s

33
Q

what % of patients recover well from Bell’s

A

85% have grades of 1-2 on house and brackmann scale

15% do poorly (grades 3-6)

34
Q

time to recover form Bell’s

A 
initiation of recovery
-within 3 weeks (85%)
-after 8 weeks (10%)
medial time to final recovery
-45 to 60 days
35
Q

poor prognostic factors in Bell’s

A 
older age
non ear region pain
complete palsy
gradual onset
vertigo
diabetes
HTN
36
Q

why is vertigo indicative of poor prognosis

A

CN 8 (vertigo) is next to CN 7 (Bell’s) and thus damage to CN 8 may signify more severe inflammation

37
Q

components of treatment of Bell’s

A

prevention of exposure keratitis
medications
facial nerve decompression

38
Q

why is a patient with bell’s at increased risk of exposure keratitis

A

decreased eye closure

decreased lacrimal gland function

39
Q

what reduces the risk of bell’s (aka why isn’t it very common to begin with)

A

preservation of corneal sensation

basically, people can feel their eye getting irritated and take action against it

40
Q

preventive interventions for exposure keratitis

A

eye lubrication

eye patching

41
Q

mainstay of therapy for Bell’s

A

steroids

  • reduce inflammation
  • reduce compression within temporal bone
42
Q

other treatments for Bell’s

A

acyclovir
-treat underlying infection
surgery
-relieve compression by fallopian canal and perineurium

43
Q

steroid regimens for Bell’s

A

prednisolone 60 mg daily x 5, taper by 10 (total 10 days)
OR
prednisolone 25 mg BID x 10 days

44
Q

how well do steroids work in bells

A

highly likely to be effective in increasing the likelihood of good facial functional recovery by about 12 %

45
Q

antiviral recommendation in Bell’s

A

may be offered to patients with new onset Bells
should be counseled that a benefit from antivirals has not been established and if there is a benefit it is likely that it is at best modest

46
Q

other therapies for Bell’s that lack evidence for support

A

facial nerve re-education
Kabat physical rehab
cutaneous electrical stimulation
acupuncture

BMB Test 2 (22 decks)

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