Bell’s Palsy Explained Clearly – Exam Practice Question

By Adem Lewis / in , , , , , , , , , , , , , , , , , , , , , , , , , /

well welcome to another MedCram calm
board vitals question and this one comes from the family medicine board review
Bank another great question here a fifty five-year-old male presents to the ER
with left-sided facial droop his symptoms started five hours ago at work
and were noticed by his coworkers the patient has an elevated blood pressure
at 170 over 101 he does not take any blood pressure medicines he reports
excessive stress due to illness in the family he also has a headache for two
weeks which mostly subsides after a good night of sleep he was sick with flu like
symptoms two weeks ago what is the best test for determining the cause of his
facial droop and we’ve gotten some requests to not give away the answer
upfront here so we can kind of work through these so let’s do it
answer choice a ask patient to frown and wrinkle his forehead be send patient for
CT scan of the head C obtain serology for flu infection d give clonidine to
lower blood pressure or e obtain a nerve conduction test for the seventh cranial
nerve so let’s go through what it is that we’re looking at and that you can
kind of tell from the answers that we’re going to be looking at while the seventh
cranial nerve specifically because of the symptom that the patient presented
with which was facial droop in the sign which shows left-sided facial droop so
the key to the answering this question is understanding the anatomy of the
facial nerve so let’s look at that the facial nerve is responsible for the
muscles of facial expression and of course they’re going to be the ones
responsible for squinting and for frowning etc first thing I want you to
look at is right here which is where the facial nerve nucleus comes from and you
can see there’s two of them there’s a right and there’s a left and it has
innervation from up above in the frontal cortex which stimulates it and then from
there it goes on out as a lower motor neuron to the various places and again
more than two branches of the facial nerve but the ones that I want you to be
aware of for squinting and for frowning is the upper division here in the lower
division now you’ll notice that there’s some interesting colors and this is to
show you one point and one point specifically and that is that the upper
division has dual or bilateral innervation whereas the lower has only
contralateral innervation so let’s review that again so the orange
innervation coming from in this case the left side and the yellow coming from the
right side and what you’ll notice if we follow this through this nerve over here
coming from the left frontal cortex is going to come down and it’s actually
going to innervate both nuclei both the left and right nuclei however the
innervation going contralateral so the left going over here to the right is
going to be seen in both the upper and lower division okay however here’s the
key the right sided input from this upper motor neuron is going to cross and
go here only to the upper okay and then you have the flip on the other side so
again here on the right side you’ve got the right upper motor neuron coming down
and going to both the right nucleus and the left nucleus but that the left comes
down and goes to both as well but as we said innervates both upper division of
the lower motor neuron so the effect is this if you have a stroke in the brain
okay let’s say you had a left-sided stroke in this case what’s going to
happen is you’re going to lose innervation wherever you see orange so
you’re not going to see any contralateral lower facial movement and
you’re going to lose some of the upper contralaterally however because the
right side has some epsilon of only the upper you’re never going to lose upper
division motor activity so that’s the key here is that a central stroke
centrally located up here in the prefrontal or frontal cortex will never
give you a problem with squinting so the upper portion is preserved because of
this dual innervation but the lower will be so they will lose the ability to
frown on the contralateral side so because of that if you ever see a person
with the problem on one side where they cannot squint and they cannot frown then
that would tell you that the problem is not centrally located up in the brain up
in the prefrontal cortex but it must be something that has affected the nerve
itself all the way back to the ipsilateral nucleus so there must be
something somewhere along here because that is the only lesion that would cause
both the upper and lower divisions of that area to have a problem so then
let’s go back to our question in this situation again the patient has the sign
of left-sided facial droop and that’s as specific as it gets so we don’t know if
this is upper this is lower this is Epsilon well it’s really not that clear
his symptoms started five hours ago it was noticed by his coworkers so
you’re getting the sense here that you’ve got to make sure that we rule out
the worst case scenario which of course is a stroke right so the patient does
have an elevated blood pressure so that makes you concerned that the patient may
have a stroke because that’s usually associated with elevated blood pressure
the fact that he doesn’t take any blood pressure medicines also kind of makes us
a little bit anxious that this could be going on he’s also got some excessive
stress in the family he’s had a headache all of these are just like wow kind of
make you worried type of thing right and then he’s got this sick flu-like symptom
from two weeks ago which may seem like a red herring but you’re not quite sure so
what’s the best test for determining the cause of ich facial droop well you’re
tempted to get a CT scan of the head to make sure that this guy doesn’t have a
stroke but you’ve got to think about what are cost effective measures that
you can put into effect to give you the most accurate
diagnosis now we’ve just said that if you were to have a stroke essential
stroke in the cerebral cortex that you would never have a loss of muscle
function in the upper division of the facial nerve and the reason for that is
is that the upper division of the facial nerve bilaterally has bilateral inputs
and so a CT scan is probably not the next best thing that you would want to
do obtaining serology for flu infection that’s probably not it either because
the flu does not cause these types of problems
clonidine is not a great medication to give acutely to lower blood pressure I
can think of much better medications especially in an emergency room to lower
blood pressure medications for instance things like labetalol or hydralazine
that could bring blood pressure down much more quickly of course you don’t
want to bring it down too fast because if you do that you could get relative
hypotension also coming off of clonidine which is an alpha-2 agonist can cause
rebound hypertension and tachycardia a nerve conduction test for the seventh
cranial nerve well we know that it’s not working the question is is why is it not
working and in fact the best answer for this is
to simply ask the patient to frown and to wrinkle his forehead and what’s that
going to do so let’s take a look at that with our picture that we had before so
again the problem is left-sided which is over here and if we ask him to frown and
to wrinkle his forehead we’re essentially testing both the upper
division of the facial nerve and the lower division of the facial nerve if
just the lower division is not working that would indicate that there’s a
problem over here with a right-sided stroke if on the other hand he’s not
able to move either the upper division of the facial nerve and the lower
division of the facial nerve then that would indicate that the problem is
actually right here which would indicate a Bell’s palsy and again the key to
understanding this topic is understanding the anatomy and
specifically that the up Division has dual innervation and the
lower division does not thanks for joining us you

33 thoughts on “Bell’s Palsy Explained Clearly – Exam Practice Question

  1. Such an impressive explanation that no one ever forgets. Thanks for the upload: Dr.Ramesh AN

  2. Clearly explained. My only issue is that this does not determine cause, only clarifies not of central origin. "Next most appropriate test" may have been better phrasing

  3. Do you ever have a case/patient that experience a third episode of Bell's palsy?
    Do you think you could get it again for the third time? Thanks

  4. I had Bell's Palsy 3 times so far. Each time I had Bell's Palsy I would have the flu then have Bell's Palsy. Also for a few days having a full blown Bell's Palsy I have the most awful pain under my ear where I'm having the side of Bell's Palsy. The last time I had it the pain lasted for about  6 days which i had to take pain meds. Now i still have some nerve damage example i can't whistle or blow a balloon, when i smile my lips can't form a u shape like a smile which is funny because some times people think I'm not responding to there joke or when waving it doesn't look like I'm smiling. Each time i had Bell's Palsy it was during high amount of stress and having a flu all at the same time. The first time i had Bell's Palsy i was 22 then the next time i had it i was 34 and the last time i had Bell's Palsy i was 38, I'm now 47. I had Bell's Palsy first on my right side then the 2nd time on left side and 3rd was on right side.

  5. Awesome video !
    Heres what I recommend eat clean and sleep . Take a stress leave from work and let your body heal if not your employer will work you till death .

  6. What caused it is nerve swelling at virus and your liver being dirty if you go to a Chinese herbalist he will give you herbs to take and in four months it'll be completely gone and in 7 days you should get your face back because that's what I did and he told me that's how you fix it.

  7. You can lower your blood pressure quickly easily and very much simpky by fasting from all but light liquids for at least 12 hours. The more regularly you can do this the better the results including excess weight loss. IDK why doc's don't tell people this but they should.
    So then anyway, to cure or prevent BP one should do what? Rebuild the brain or what? What, how?
    I had been taking metformin for the past couple years when now I get BP. How n why? Metformin depletes B12, a nerve nutrient. Had I known I would've told my PCP to go take a flying leap, the m..f'er !!

  8. A provider that did not get a CT and is confident in this diagnosis just on assessment findings is someone ambitions, one would say better cover your ass with a CT especially with associated H&P findings…Convoluted test question that does NOT apply to real life, great explanation though.

  9. Would it be inappropriate or incorrect, In this video, to bring up Pontine stroke, which I believe can also affect face and brow with paralysis… It is my worry that ER docs will dismiss patients who present brow paralysis early, under the assumptive diagnosis of Bell's Palsy, thereby missing the opportunity to treat a pontine stroke in the first 3 'golden hours'… treatment which could save function and spare suffering. Please forgive any ignorance or naivety in my comment, I am a guitar teacher.

  10. I had suffered Bell Pasley on both side of my face. 1st on the Right. Once that recovered 100%. A month or 2 later my left side was affected. But ive only recovered around 80% of my normal nerve function. Its been almost 5 years. Doctors didn't tell me what caused it. Only gave me anti-inflammatory and stent me on my way.

  11. He tried to explain it well. Issues here are his use of the words 'never', 'ever', 'always' !!! These words are usually avoided in medical communication.

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