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What Is Bell's Facial Palsy? Its Causes, Symptoms and Treatment.
Bell’s palsy is the most common form of acute facial paralysis or weakness (inability to control facial movements) on one side of the face, that results from the inflammation (swelling) of or a lesion in the facial nerve (Cranial Nerve VII palsy) after it exits the skull.
The facial nerve supplies the muscles of the face and control many functions such as smiling, frowning, closing the eye, raising eyebrows, lacrimation (production of tears) and salivation.
Facial nerve also supplies stapedius (muscle attached to stapes) in the ear and carries taste sensation from the anterior two-thirds of the tongue.
The forehead muscles receive nerve supply from both sides of the brain (both hemispheres), thus it is important to see for forehead wrinkling and whether or not the forehead muscles spared.
If facial weakness were caused by a problem in one of the sides of the brain, the person would still be able to wrinkle his forehead. However, if the weakness is due to a problem in the facial nerve itself, the forehead muscles are not spared and all the movements are compromised on the same side of the face, whereas facial movements on the other side of the face are intact, including wrinkling of the forehead.
How does Bell's Palsy occur?
It is possible that one morning you wake up only to find that one side of your face is not working properly, you cannot close your eye, and you are having difficulty with smiling or even frowning. If there is no other cause you can think of, and it has appeared all of a sudden, most probably it is Bell's Facial Palsy.
Bell’s palsy develops abruptly, mostly overnight, and maximum facial weakness is attained by 48 hrs as a rule.
Pain behind the ear or discharge from the ear may precede the paralysis for a day or two. Unilateral (on one side) taste sensation may be lost and hyperacusis (sensitivity to loud sounds) may be present.
MRI may reveal swelling of the facial nerve and, in some cases, entrapment of the swollen nerve in the temporal bone.
Prognosis in Bell's Facial Paralysis
Bell’s palsy is usually temporary and approximately 80% of patients recover spontaneously and achieve near-normal to normal facial movements within a few weeks or months, even without treatment.
Electromyography is considered to be of some prognostic value; if there are evidences of degeneration of nerve fibers, it indicates that there will be a delay of about 3-4 months before regeneration occurs, and that normal functions may still not be achieved.
Bell’s palsy affects about 60 in every 10,000 individuals. So it isn’t rare, is it?
What Causes Bell's Palsy?
It is believed to be caused by reactivation of a pre-existing latent or dormant infection by some viruses (Herpes zoster virus, and Epstein Barr virus), though a causal role is yet to be proved.
However, certain conditions like accidents or surgery (facial nerve damage), extremely cold climate, metabolic conditions and emotional stress may also trigger development of acute facial paralysis or weakness.
Congenital facial paralysis is also not uncommon, especially when delivery is conducted with the use of forceps.
It is only when a definite cause for facial paralysis cannot be defined that it is termed Bell’s palsy.
Symptoms of Bell's Palsy
The cranial nerve seven (or Facial nerve) paralysis interferes with facial expressions and other movements on the side of the nerve damage.
Thus, the symptoms of Bell's palsy are:
- The corner of the mouth droops and cannot be lifted, thereby causing difficulty in smiling, and even talking.
- The facial creases and skin folds are effaced.
- The forehead is smooth and unfurrowed, even on attempted frowning.
- Eyelids will not close or close with difficulty.
- Upon attempted closure of eyelids, the eyes on the paralyzed side roll upward (Bell’s phenomenon).
- Excessive tearing or a dry eye.
- The lower lid sags and falls away from the conjunctiva, permitting tears to spill over the cheek.
- Food collects between the teeth and lips.
- Saliva drools from the corner of the mouth.
- Loss of taste sensation on the affected side.
- Affected side may feel numb.
- Pain may be present in or behind the ear.
- There may be an increased sensitivity to loud sounds (hyperacusis).
How is Bell's Palsy Diagnosed?
Diagnosis of Bell’s palsy is essentially through elimination of other causative conditions of facial weakness or paralysis. There are many other causes of acute facial palsy that must be considered in the differential diagnosis of Bell’s palsy.
Lyme’s disease (due to infection with Borrelia burgdorferi) can cause unilateral or bilateral facial palsies, mainly in the endemic areas.
The Ramsay-Hunt syndrome also causes severe facial palsy associated with vesicular eruptions in the ear canal. Sarcoidosis and Guillain Barre Syndrome often result in bilateral facial palsy.
Apart from these, facial paralysis may also be observed in meningitis, leprosy, stroke, diabetes and acute HIV infection.
Bell's Palsy Treatment
Each individual presents with Bell’s (facial) palsy differently. Some may have only incomplete loss of facial movements, which has greater chances of complete recovery and there is no need for treatment per se, while some may present with complete paralysis where prompt treatment (within 2 days after the onset) is mandated.
Analgesics may be given to relieve pain if it there. Steroids are used mainly to reduce the swelling of and around the nerve and thus have proved efficacious in the treatment of Bell’s palsy, whereas anti-viral drugs have not shown much promise, unless the causal role of Zoster or Epstein Barr virus could be demonstrable.
Symptomatic treatment measures include:
- Use of eye-cover or paper tape to shut the upper eyelid during sleep and prevent corneal drying (xerosis), as corneal drying and infection is one of the major complications of Bell’s palsy.
- Massage and exercise of affected muscles
- Use of lubricants or artificial teardrops during working hours and ointment for application during sleep, again to prevent corneal drying and infection.
- A course of glucocorticoids, given as prednisolone 60-80 mg daily for the first five days and then tapered over the next five days, appears to shorten the recovery period and modestly improve the functional outcome.
Do you know of someone with Bell's palsy?
Other Treatment Modalities
Once paralysis has set in, irrespective of whether or not it needs treatment, it is important to maintain the tone of affected muscles of the face as well as to stimulate the facial nerve. Physiotherapy is thus recommended on a regular basis these days, which also involves education about some facial muscle exercises to aid in early recovery.
Acupuncture has been reported to be beneficial in some cases.
TCES (Transcutaneous Electrical Stimulation) may be tried in cases of unresolved facial paralysis.
Botox injection is also emerging to be one of the recent advancements in the treatment of Bell’s palsy.
In long-standing cases of facial palsy where significant recovery has not occurred even after 6 months to a year, Smile surgery is one procedure that can bring back the smile for people with Bell’s palsy. It involves re-innervation of the degenerated nerve fibers. It is also done in cases of paralysis due to facial nerve damage because of trauma or surgery.
Complications with Bell's Palsy
The major complication in patients of Bell's palsy is corneal dryness (irritation) and infection.
Another common complication of Bell’s palsy is faulty or anomalous regeneration of fibers during recovery, which may result in other bothersome phenomena, for instance, closure of eye may cause retraction of the mouth, or anomalous tears (crocodile tears) may occur with any activity of the facial muscles, such as eating.
These complications are observed in about 8% of people after recovery from Bell’s facial palsy.
You're Not Alone!
Lastly, I hope you remember Sylvester ‘Rocky’ Stallone. Yes, he has had Bell’s palsy since birth and that is how he could pull off that amazing yet peculiar look he was well known for.
There’ve been some other eminent personalities too who have been affected by facial paralysis once, like Salman Khan, Pierce Brosnan, George Clooney, Allen Ginsberg, Katie Holmes (yes, she too!) and many more. Therefore, have heart and just know that you are not alone.