Bell’s Palsy – causes, symptoms, diagnosis, treatment, pathology

Bell’s Palsy – causes, symptoms, diagnosis, treatment, pathology


Bell’s palsy, named after the surgeon Charles
Bell who first described it, is when there’s weakness or paralysis of the muscles on one
side of the face, caused by damage to the seventh cranial nerve, which is the facial
nerve. The underlying cause of cranial nerve damage is idiopathic which means it’s unknown,
so when there’s facial nerve a paralysis from a known cause like a stroke, a tumor,
or trauma, it’s not considered a Bell’s palsy. George Clooney had this disorder for
nine months when he was a teenager. Broadly speaking, the nervous system has two
parts: the central nervous system, which consists of the brain, brainstem, and spinal cord,
and the peripheral nervous system, which consists of all of the nerves that fan out from the
central nervous system. Peripheral nerves that emerge from the brain and brainstem are
called cranial nerves, and there are a total of 12 pairs of cranial nerves. The seventh cranial nerve, the facial nerve,
emerges from the brainstem, and then enters the temporal bone where it travels through
a narrow, Z-shaped canal, called the facial canal. The facial nerve exits the skull through
a tiny hole called the stylomastoid foramen. From there, the facial nerve branches off
to different facial muscles that help with facial expression, like the ones you use while
whistling to your favorite song. Ultimately, control of each side of the face
comes from a region of the brain called the motor cortex. For example, let’s start with
the lower half of the right side of the face. An upper motor neuron extends down from the
left motor cortex, goes across the midline in the brainstem to the right side, and then
meets with a right lower motor neuron which hitches a ride on the right facial nerve.
For the upper half of the right side of the face, things begin similarly. There’s another
upper motor neuron that extends down from another region of the left motor cortex, also
goes across the midline in the brainstem to the right side, and meets with another right
lower motor neuron which also hitches a ride on the left facial nerve. The one huge difference
is that there’s another upper motor neuron that extends down from a region in the right
motor cortex, and stays on the ipsilateral or same side to meet with same the lower motor
neuron. In other words, there are two upper motor neurons, one from each side of the brain,
giving input to one lower motor neuron. The left half of the face is similarly innervated.
So that means that each facial nerve contains motor information for the lower face coming
from the contralateral motor cortex, and motor information for the upper face coming from
both motor cortices. The facial nerve also innervates the sublingual
and submandibular glands, which secrete saliva, the lacrimal gland which produces tears, and
mucous membranes of the nose, mouth, and nasopharynx. In the ear, it innervates the stapedius muscle
which dampens the vibration of the stapes, a small bone that help transmit vibrations
from the eardrum; this protects you from loud noises. The facial nerve also carries sensory
information about taste from the anterior ⅔ of the tongue. So if you lick an ice cream
cone – that’s the facial nerve registering the flavor! Bell’s palsy occurs when the facial nerve
gets damaged, and although the precise cause is unknown, it’s often associated with viral
infections like herpes simplex virus, Epstein-Barr virus, and varicella-zoster virus, as well
as the bacteria Borrelia burgdorferi which causes lyme disease. Regardless of the cause,
when the facial nerve isn’t able to conduct the brain’s signals, the result is that
there’s weakness or paralysis of the facial muscles. Now, it’s important to distinguish Bell’s
palsy from other causes of facial palsy like a stroke. If the underlying problem is in
the brain or brainstem before the upper motor neurons cross the midline, it’s called an
upper motor neuron lesion. This causes paralysis of only the lower half of the face on the
contralateral side as the lesion, since the upper half of the face is still receiving
some information from the ipsilateral motor cortex. However, if there’s a lower motor
neuron lesion like in Bell’s palsy where the facial nerve is damaged, information from
the contralateral and ipsilateral motor cortex is lost for the upper face, as well as information
from the contralateral motor cortex for the lower face. This results in the paralysis
of all the muscles on the side of the affected nerve. The main symptoms of a Bell’s palsy can
be seen by looking at a person’s face. There’s an absence of the nasolabial fold, which is
the skin fold that runs from the side of the nose to the corner of the mouth. There’s
also drooping of the eyelid and drooping of the mouth. In some people, there’s also
dryness of the affected eye or mouth because the facial nerve innervates the lacrimal,
submandibular, and sublingual glands. Sometimes there’s also hypersensitivity to loud noises
and a loss of taste sensation on the anterior ⅔ of the tongue. The diagnosis of a Bell’s palsy is based
on identifying that the problem is with the facial nerve and not finding an alternative
explanation like a stroke or brain tumor. Bell’s palsy affects each person differently.
Most people recover within 6 months after the onset, but some people develop permanent
facial weakness or paralysis. Treatment isn’t needed in all cases of Bell’s palsy, but
in some severe cases, corticosteroids can help reduce the nerve inflammation and speed
up the recovery. All right, as a quick recap. Bell’s palsy
occurs when there’s a disruption of the facial nerve from an unknown cause. The most
common symptoms are weakness or paralysis of both upper and lower facial muscles on
one side of the face due to the loss of all lower motor neurons. Bell’s palsy is treated
with corticosteroids, but in most cases, symptoms usually subside on their own.

96 Replies to “Bell’s Palsy – causes, symptoms, diagnosis, treatment, pathology”

  1. Yes… I love your videos. My mind is a sponge and you are good nourishment. My goal though.. is dna de novo mutation repair. So I need to condense my knowledge of proteins. 27MAR2018

  2. I had this as a kid and my mom told me it’s hereditary. She had it as a kid and so on. But this is so amazing to learn. I have a slight damaged nerve on my right side of my face and I feel like I never looked the same.

  3. Ahhh… Can I ask something? I wonder that how do you make this video? Which webpage or book do you usually use for video?
    // I'm not good at english, so if you dont understand, i will write with more detail! Thank you!

  4. your teachings are always good but please focus more on treatment and more detailed information to be given. Thank you.

  5. Hi Osmosis, could you please make a video on types of Intracranial hemorhage (epidural, subdural, sub arachnoid)?
    Oh and AWESOME video as usual!!!

  6. I really love the way you present the disease, its understandable and the illustrations are pretty good (and cute tho)! Thank you.

  7. Videos are amazing! Thank you for making things easy. Can you please make Dental topic related videos. That will be a great help ☺️ thank you!

  8. when you say: control for the upper 1/2 of right side of face, another UMN extends down from another region of left motor cortex, also goes across midline in brain stem to right side and meets with another LEFT LMN, which also hitches a ride in LEFT facial nerve… Don't you mean: meets with another RIGHT LMN, & RIGHT facial nerve?

  9. Half of my brain is interested to listen and the other half is like "Make your points faster"

  10. Thanks for the information and making it so clear and understandable. This just happened to my mom and I am distraught for her. I pray she recovers quickly.

  11. Great video…very informative! However, I would like to see more about treatments from a nursing standpoint, like facial massage and/or exercises when patient is able, and possible patient teaching. Thank you.

  12. Thanx! Woke up,……thought,….my face feels odd,….brushed my teeth,….face was numb! Like a trip to the dentist. WOW! You think,..is this a stroke? Went to hospital,….was reassured,..can happen any time any age. I’m very healthy and this is quite a surprise! A reminder of good health perhaps. July 31st 2018. It’s now September,……I’m my smiling self again! Thanx!

  13. My cheekbones have become very protruding and a bit wide I look older than my age and I have numbing feeling in my face

  14. You’re amazing bro, You made my review easier more power to you dude keep up the good work. Can you make a videos about immunization, Thanks.

  15. I had this for like two weeks, I'm glad I didn't have it for as long as other people at first I thought I had a mini stroke I was shook

  16. Why did I get this disease. I am suffering this for 2 years. I cannot even study or memories anything. Not even making friends or hanging around with them. I am frustrated

  17. What if the entire side of the face is paralyzed, except the eye does start closing a few hours after onset? A ct scan ruled out stroke.

  18. I got Bell's Palsy 3 weeks ago, I also uploaded a video showing it – but I felt insecure and ashamed 🤔😰🤕

  19. Can someone please tell me what did you do when you get the first time feels like that your having bell's palsy what did you do firstly for it plz

  20. I just had to take my dad to the urgent care tonight because his face looked like it was melting off. Turns out it was just this, thankfully.

  21. someone tell me why the contralateral side affected in Bells palsy?? it should be normal because lower levels not related with contralateral side!

  22. I just recovered from this. Took exactly a month.
    It sucked because i hate multiple pet birds and for a month i couldn't whistle to them.

    Everyone make sure to get eye drops and to massage your face daily.

  23. I also have my bell's palsy for one year and I'm not healed anymore what should I do to improve my face and what is the right procedure in my face

  24. I have bell's Palsy
    It's my 5th day and I just went to a doctor today and that's the time I knew that I'm suffering for bell's palsy
    I cried while my doctor explains my condition

  25. I was diagnosed with multiple sclerosis 1 month after I turned 45. My grandma is 96 and had it since she was in her 20s. I have been on Copaxone, the first year was daily and now I am on 40 mg, 3 times a week. It made a tremendous difference for me. Although the fatigue is what really gets to me. When I do too much, I do start to feel weak. My MS got significantly worse and unbearable Last year, a family friend told me about Organic Herbal clinic and their successful MS TREATMENT, I visited their website ww w . organicherbalclinic. co m and ordered their MS Formula, i am happy to report the treatment effectively treated and reversed my Multiple Sclerosis(MS)), most of the symptoms stopped, I'm able to walk and eat well, sleep well and exercise regularly., I'm pretty active now and my attitude is extremely positive.

  26. can someone explain why bells palsy affects contralateral on lower side . i ithink it shall affect ispi.
    also on upperside why shall there be any effect on the contralateral side of the lesion

  27. I am recovering from Bell's Palsy (end of week 2) and I started having acupuncture. There is no way to know if the acupuncture is making the difference or if I'm recovering on my own. However, I feel that I experienced a huge improvement directly after the acupuncture sessions, so I would encourage others to try it. I was a skeptic, but I feel so strongly that it helped that I'm commenting so that other people can consider it as an option. This has been upsetting and scary. If you have Bell's, stay positive, rest a lot, listen to your doctor, and consider acupuncture.

  28. I might not remember anything from this lesson but I will always remember that George Clooney had Bells palsy

  29. peope with bells palsy and facial palsy what ever the difference is don't need plastic surgery they have a right to be how they are ignorant ppl need new brians

  30. Four things you could have mentioned: Current Treat,1) Acyclovir and Predisone, 2) Physical Therapy Exercises, (What???)
    3) Surgery maybe needed, (What???)… Anybody can get this disease at almost any age… Great video, move videos please…

  31. I’m 36
    My Right Side Of My head has been numb for 5wks now (Partial Lobe to my eyebrow) no facial side effects tho, but I nod off A lot, had a nerve test done and couldn’t feel anything, I can’t fee a col
    MRI comes up as a stroke but under no treatment. I can’t handle the light or loud noises n seams to be getting worse.sometimes I think I’m typing something but typing just random letters etc
    Iv officially stumped my GP

    I need help

  32. bells palsy is cool deosnt need treating its nice unique and rare sod what idiots say and I wish I had facial or bells palsy my lips are so comman so ordinary

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