Bell's Palsy

Symptoms: Sudden weakness/paralysis on one side of the face, drooping eyebrow and mouth, drooling from one side of the mouth, and difficulty closing the eyelid.

Causes: The exact cause of Bell’s palsy is not known. Reduced blood flow to the cranial nerve, viral infection, or problems with the immune system may be the causes.

Risk Factors: Pregnancy, preeclampsia, obesity, hypertension, diabetes, and upper respiratory ailments.

Prevalence: The annual incidence is 15-20 per 100,000, with 40,000 new cases yearly. The lifetime risk is 1 in 60. The recurrence rate is 8% to 12%.

Severity: Mild to severe

Which doctor to consult: General Physician, Neurologist, ENT specialist, Ophthalmologist

OVERVIEW:

Bell's palsy is a condition that affects the face, causing paralysis or weakness on one side of the face. It is named after Charles Bell, a Scottish anatomist who first identified the disorder. Bell's palsy occurs when one of the nerves responsible for controlling facial muscles is damaged or not functioning correctly. It is the most common cause of facial paralysis.

Fortunately, most people recover fully within a few months. Taking steroid tablets within 72 hours of the onset of symptoms can further improve the chances of a complete recovery. Around 80% of people with Bell's palsy show signs of improvement within three weeks, and most recover completely within 2-3 months. However, about 5-10% of people may experience some minor weakness that remains permanent. In rare cases, there may be little or no improvement.

SYMPTOMS:

The symptoms of Bell's palsy may include:

• Paralysis on one side of the face.

• A drooping eyebrow and mouth.

• Drooling from one side of the mouth.

• Difficulty closing one eyelid.

• Eye dryness or watering.

• Dry mouth.

• Twitching and weakness of the face.

• Facial pain around the ear on the affected side.

• Altered or loss of taste on one side of the tongue.

• Sensitivity to noises.

CAUSES:

The causes of Bell’s palsy may include:

• Viral infections like herpes simplex or varicella (chickenpox)

• Infection of a facial nerve and resulting inflammation, such as Lyme disease

• Impaired immunity due to sleep deprivation, stress, minor illness, physical trauma or autoimmune syndromes

• Damage to the myelin sheath (the covering that insulates nerve fibres)

RISK FACTORS:

The risk factors for Bell's palsy include:

• Pregnancy

• Preeclampsia

• Obesity

• Hypertension

• Diabetes

• Upper respiratory ailments

POSSIBLE COMPLICATIONS:

Some complications related to Bell palsy are as follows:

• Corneal dryness leading to visual loss: Bell's palsy can result in a weakening of the muscles in the eyelid, which in turn can make it difficult for the patient to blink properly and may cause the eyelids to remain partially open. This can lead to dry eyes and blurred vision, especially if the condition has also reduced the production of tears. 

  The cornea, which is the clear outer layer of the eye, is highly sensitive to dryness, and persistent dryness can cause the corneal cells to flake off and ulcers to form. Corneal ulcers can be painful and may result in infection or scarring of the cornea, which can ultimately lead to a loss of vision.

• Permanent damage to the facial nerve: The tightening and contraction of facial muscles can lead to a greater degree of asymmetry in the face, which is particularly noticeable when one eye appears smaller or a cheek appears larger. Furthermore, loss of nerve function may cause swelling in the affected muscles.

• Abnormal growth of nerve fibres: After Bell's palsy, the facial nerve heals by developing new nerve fibres. Nonetheless, there are instances when these nerve fibres regrow irregularly. For instance, the nerve fibres that should link the brain to the muscles of the mouth may grow back and connect the brain to the muscles of the eyelid. This could lead to a condition called eye-mouth synkinesis (a person may unintentionally close one eye while attempting to smile). Conversely, it may also cause reversed jaw winking (the facial muscles may contract, leading to twitching of the mouth's corner or dimpling of the chin while blinking simultaneously). 

PREVENTION:

Currently, there is no known way to prevent Bell's palsy. Although, it is linked to certain viral infections, not everyone who has those viral infections develops Bell's palsy. If you have risk factors for the condition, like diabetes, obesity or high blood pressure, managing them well may help reduce the risk.

WHEN TO SEE A DOCTOR:

It is advised to consult a doctor as soon as you notice muscle weakness in your face or any symptoms of Bell’s palsy.

DIAGNOSIS:

Physical examination: During the medical evaluation, the physician will examine the upper and lower facial muscles on one side of the face, such as the forehead, eyelid, and mouth muscles, to detect any weakness that has occurred within the past three days. The doctor will also eliminate any other potential causes of facial paralysis during the examination.

Imaging studies: In the majority of cases, there is no requirement for regular laboratory or imaging studies. Nevertheless, in some instances, these tests can verify a diagnosis or exclude other diseases or conditions that can lead to facial weakness. If the reason behind facial weakness cannot be identified, it is referred to as Bell's palsy. Imaging studies can be useful if the facial weakness shows a gradual progression or if there is also a loss of taste and hearing sensitivity along with facial expression.

Electromyography and nerve conduction studies: Electromyography and nerve conduction studies can provide information on the degree of the disorder and the probability of recovery.

Laboratory tests: Laboratory tests for Lyme disease and other viruses may be considered when choosing a treatment plan.

TREATMENT:

Treatment for Bell’s palsy includes medications, eye protection, surgery, and other therapies.

Medications:

1.    Steroids: Steroids help lower inflammation and swelling and increase the probability of facial nerve function recovery. The most commonly prescribed steroid is Prednisolone.

2.    Anti-viral medicines: Antiviral medicines may be prescribed in addition to steroids to help improve the chance of recovering facial function. Antiviral medications like valacyclovir or acyclovir may be given in combination with steroids.

3.    Analgesics: Patients experiencing pain with Bell’s palsy may find relief by taking painkillers/analgesics such as aspirin, acetaminophen, or ibuprofen. 

4.    Eye drops: If a person has trouble closing one/both eyelids, lubricating eye drops or eye patches may help keep the eye moist and protect it from debris or injury, especially while they are sleeping. The doctor may advise eye pods or goggles and eye drops or eye ointment.

Mouth care: As the facial muscle may not be functioning fully, food may become lodged around the teeth and gums on the affected side. Make sure you remember to clean this area well and remove all debris after eating.

Physical therapy: Facial massage or acupuncture may provide some improvement in facial nerve function and pain. Try gently raising the eyebrows, wrinkling the nose, flaring the nostrils, lifting one corner of the mouth and then the other, smiling without showing the teeth and then smiling with teeth showing, and bringing the eyebrows together in a frown. However, seek medical help if you feel exercises are making your symptoms worse.

Cosmetic or surgical therapy: Sometimes, a crooked smile or an eyelid that does not close can be fixed using cosmetic or reconstructive surgery. If the facial muscles start to spasm, injecting botulinum toxin (Botox) can be useful. There are several surgical techniques available that can enhance the cosmetic appearance.

LIVING WITH:

Bell's palsy is typically a one-time event, but approximately 1 in 14 people may experience additional episodes in the future, often years later. This is more probable if you have family members who have had Bell's palsy as well.