BELL’S PALSY AND ITS MANAGEMENT
What is Bell's Palsy?
Bell's Palsy is also known as Idiopathic Facial Paralysis (IFP). It is a well-known neurological disorder resulting in a unilateral temporary weakness of the facial muscles. It results in a partial or one-sided droopy face, rarely on both sides, due to dysfunction of the seventh cranial nerve that is the facial nerve. Bell's Palsy got its name after the Scottish anatomist Charles Bell, who first described it in the 19th century.
Role Of Facial Nerve
The facial nerve produces both motor and sensory functions to our face. It includes:
- muscles of facial expression, eye blinking, and jaw
- providing the sense of taste
- supply to the salivary glands and the tear-producing glands
- carry impulses to the muscles of a small bone in the middle ear
In the majority of cases, there is a sudden onset of symptoms over a 48 to 72 hour period and gradually resolve or recover with or without treatment in a few month's time. In some of the cases, residual muscle weakness might last longer or even stay permanent.
Who Might Be Prone Or At Risk
Bell's Palsy is said to affect men and women equally. Certain conditions might trigger the onset of Bell's Palsy, which include the following:
- Pregnant women and preeclampsia
- Autoimmune diseases, and infections such as Lyme disease
- Family history of Bell's Palsy
- Diabetes; People with diabetes have a 26% more chance of developing Bell's Palsy than non-diabetics. Similarly, recurrence is also more common among non-diabetics.
- Viruses; Herpes Simplex Virus (cold sores) or Herpes Zoster Virus (shingles) or mononucleosis (Epstein-Barr Virus)
- Hypertension
Symptoms Of Bell's Palsy
The symptoms of Bell's Palsy may develop suddenly and might create the fear of stroke, but stroke causes weakness of other parts of the body as well. They usually start abruptly and reach peak severity within 48 to 72 hours. The symptoms gradually improve in 3 weeks, and almost 80% of the people recover entirely after three months.
The most common sign and symptoms are:
- Weakness and facial drooping normally just on one side of the face.
- Difficulty speaking, eating, or drinking.
- Drooling
- Lagophthalmos; Inability to close the eye due to dryness
- Eyes irritation, i.e., excessive tearing in one eye (Epiphora) or dryness
- Posterior auricular pain
- Hyperacusis; reduced tolerance to loud noise
- Otalgia; ear pain and tinnitus; ringing in ears
- Facial muscle twitching or hyperactivity
- Facial pain or abnormal sensitivity
- Headaches
- Complete or partial loss of taste
- Dysarthria; difficulty speaking
- Blurred vision
Causes Of Bell's Palsy
The exact cause of Bell's Palsy is unknown. The seventh cranial nerve (facial nerve) is swelled and inflamed in patients with Bell's Palsy.
Scientists believe that a viral infection most likely triggers it. Reactivation of an existing or dormant virus may cause this disorder. Other causes may include:
- Impaired immunity from anxiety
- Inflammatory conditions like sarcoidosis
- Physical trauma to the facial nerve
- Insomnia or sleep deprivation
- Any illness or autoimmune diseases
- Brain tumor
- Stroke
The facial nerve pathway is very complex; it originates in the pons area of the brainstem, where it has two roots, one for sensory function and the other for motor function, which eventually fuses to form the facial nerve. Now, the facial nerve traverses through the fallopian canal (a bony canal through which the nerve travels along the side of the face), where it branches into tiny nerve fibers.
So basically, what happens is that the facial nerve is inflamed that causes swelling in reaction to any infection. Even in case of minor swelling of the nerve, it pushes against the skull that causes pressure in the fallopian canal leading to blood and oxygen restriction to the nerve cells which control facial muscles.
As the inflammation subsides with time and in cases where recovery is fast, only myelin sheath (insulating fatty layer on nerve fibers) is damaged. The nerve starts to function again in five or six months.
Can Bell's Palsy Occur More Than Once?
It is sporadic to have a recurrence of Bell's Palsy, but one cannot rule it out. It may happen within two years of the first incident. You are more prone to conceive it again if you have a family history of Bell's Palsy.
The Diagnosis:
Your healthcare provider first performs a physical examination based on the symptoms to understand the extent of the disorder to rule out any other possible cause of the paralysis. There is no specific laboratory test to diagnose Bell's Palsy. The practitioner examines the muscles for upper and lower facial weakness, including the forehead, eyelids, or mouth. The further detailed examination includes the following:
- Otologic Examination: Tuning fork examination and pneumatic otoscopy by using a tool to diagnose acute or chronic otitis media (middle ear infection)
- Ocular Examination: To check if the patient can close the eye of the affected side completely
- Oral Examination: It is conducted to check the function of taste buds and salivation.
- Neurologic Testing: Nerve testing is performed to find out the motor, cerebellar and sensory impairments.
A test called electromyography or EMG is conducted. The medical professional uses thin electrode wires to insert them in the muscle to assess changes in electrical activity when a muscle is at rest or during movement. It confirms the presence of nerve damage, its severity, and the extent of nerve involvement.
Other Testing
As discussed earlier that there is no particular diagnostic test available to diagnose Bell's Palsy, but some tests are performed to rule out other disorders and to identify any infection:
- HIV screening
- Complete Blood Count (CBC)
- Erythrocyte Sedimentation Rate
- Thyroid Function
- CSF analysis
- Blood and Serum Glucose
- Nerve excitability test
- CT (Computed Tomography)
- Magnetic Resonance Imaging (MRI)
Grading of Bell's Palsy
House and Brackmann created the grading system for Bell's Palsy categorized from grade 1 to 6:
Grade 1: Normal facial function
Grade 2: Mild dysfunction
Grade 3: Moderate dysfunction
Grade 4: Moderately severe dysfunction
Grade 5: Severe dysfunction
Grade 6: Complete paralysis
Management And Treatment
The goal of management and treatment of Bell's Palsy is based on the following:
- Improvement in the facial nerve
- Reduction of nerve damage
- Prevent complications from corneal exposure
Treatment includes corticosteroid therapy, antivirals, and topical eye ointments, and artificial tears. Over-the-counter painkillers are used to reduce facial pain.
At home, you can use an eye patch for dry eyes, a warm moist towel to relieve your pain, massage, acupuncture, and physiotherapy exercises to stimulate the muscles of your face. Electrotherapy is given to the affected muscles to provide muscle innervation in order to prevent muscle degeneration.
In rare cases, surgery is the option left that includes facial nerve grafting or decompression and reconstructive surgery.
Prognosis Or The Outlook
Generally, the prognosis of Bell's Palsy is very good. 85% of individuals show spontaneous improvement within three weeks and eventually recover normal facial function. Some people might still have dysarthria (difficulty speaking) for longer than a month. The recovery depends upon the extent of nerve injury. Complete recovery takes three to six months. Rarely it happens that the facial weakness lasts longer than that, or healing doesn't happen at all.
Potential Complications
the majority of individuals recover completely without any complications. However, in severe cases following complications may result:
- The facial nerve has motor and sensory functions, and damage to the entire nerve may occur in some cases.
- Excessive dryness can cause eye infections, ulcers, or even loss of vision.
- Synkinesis (involuntary facial movement with the voluntary movement of another facial muscle), for example, sudden involuntary eye closure with a smile.
Conclusion
Bell's Palsy has a good prognosis. Call your healthcare professional if you see any signs of Bell's Palsy because prompt treatment may speed up the recovery time and prevent you from any complications.
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