Bell’s palsy is the most widespread trigger of acute unilateral peripheral facial nerve paralysis with an estimated number of cases varying between 20 and 30 per 100,000 people a year. It is a major cause of lower motor neuron type facial palsy, making up about 60 to 70% of all instances of the phenomenon. 

Bell’s palsy does not have a prominent sex predilection, with both sex being equally susceptible. 

It may develop at any age, but the median age of manifestation is in the range of 40 years. It is important to point out that the condition is the least prominent in children younger than 10 years. 

But, the outbreak becomes more common with age, with its highest occurrence among those above 70 years. No lateralisation bias is present, and both sides of the face are involved equally. If you are preparing for the NEET PG examination, then you should know about Bell’s palsy, its causes, symptoms, diagnosis, and treatment.

Read on to learn more about Bell’s palsy!

What is Bell’s Palsy? 

Bell’s palsy is a neurological disorder, which is described by the acute occurrence of facial muscles weakness or paralysis on one side of the face. This normally causes a sagging of one side and hence an imbalance in the face.

People can have trouble making an even smile and can find difficulty closing their eyes on the side which has been affected. The weakness is usually temporary and in most instances, it will improve gradually within several weeks, although each individual may take a different time.

What Causes of Bell’s Palsy?

The main causes of Bell’s palsy include swelling and the narrowing of the seventh cranial nerve, which is the facial nerve. This nerve is responsible for controlling the facial expression muscles, assisting in taste in the other two-thirds frontal part of the tongue, as well as tear production within the lacrimal glands.

Each individual has two facial nerves, one for each side of the face. When inflammation affects one of these nerves, it disrupts normal signal transmission, resulting in unilateral facial muscle weakness or paralysis. This has clinically manifested itself through sudden onset facial drooping, failure to close the eye, and facial expression asymmetry.

• Potential Viral Triggers

Although it has been found that the causality is idiopathic, several varieties of viral infections and innumerable perceptions have been seen in the pathogenesis of Bell’s palsy because of the potential it possesses in a facial nerve being inflamed. These include:

• Herpes Simplex Virus Type 1 (HSV‑1): Commonly associated with cold sores.
• Varicella-Zoster Virus: The causative agent of chickenpox and shingles.
• Epstein-Barr virus (EBV): Responsible for infectious mononucleosis.
• SARS-CoV-2 (COVID-19): Emerging evidence suggests an association with facial nerve palsy in some cases.

• Other Contributing Factors

Besides viral aetiologies, some physiologic and immunologic stressors could predispose the development of Bell’s palsy, especially amongst individuals with immunocompromised states. These include:

• Psychological or physical stress
• Acute or chronic illnesses
• Sleep deprivation
• Minor physical trauma
• Autoimmune disorders

Although there has been a lot of research, in most occurrences, no definite cause or trigger can be found. It is therefore commonly described as idiopathic peripheral facial palsy, and the treatment response goes toward symptomatic relief and early intervention to encourage nerve recovery.

What are the Symptoms of Bell’s Palsy?

Acute facial paralysis that usually develops on one side of the face is the most palpable symptom of Bell’s palsy. This causes an outward sagging effect which encompasses:

• Forehead
• Eyebrow
• Eye and eyelid
• Corner of the mouth

The disease has symptoms that often develop quickly, with the worst symptoms in 48 to 72 hours. Depending on the extent of nerve involvement, it can range in severity to include mild muscle weakness to full facial paralysis.

Due to the motor dysfunction, individuals often struggle to perform typical facial movements such as:

• Raising the eyebrows
• Wrinkling the forehead
• Blinking or closing the eye
• Smiling or grimacing

Although the face might be heavy and feel numb, the sensory nerves are not affected. Hence, the capacity to appreciate the sense of touch, temperature, and pain in the affected side is usually maintained.

Besides motor impairment, Bell’s palsy can be associated with a host of different symptoms, including:

• Excessive drooling
• Dryness of the eye 
• Difficulty in speaking, chewing, or drinking
• Facial or peri-auricular pain
• Headache
• Altered or lost sense of taste
• Ringing in the ears (Tinnitus)
• Increased sensitivity to sound (Hyperacusis)

This presentation is typically unilateral and self-limiting in most cases, although the range and severity of symptoms may vary. Prompt diagnosis and early treatment, particularly with corticosteroids, are crucial for improving recovery outcomes.

What is the Diagnosis of Bell’s Palsy?

The diagnosis of Bell’s palsy is primarily clinical, based on the patient’s presenting symptoms and physical examination findings. The first stage in diagnosis by a health professional would be to obtain a thorough medical history of facial weakness, its timing, duration and character.

An important part of the physical examination entails evaluation of facial muscle activity, and in this respect, the patient is usually asked to carry out certain actions like raising eyebrows, closing eyes, smiling and puffing cheeks. 

Although Bell’s palsy is a common, ordinary illness, the possibility of other systemic and neurological diseases sharing the same manifestation modes should be taken into consideration. These include:

• Cerebrovascular accidents (stroke)
• Sarcoidosis
• Lyme disease
• Middle ear infections (bacterial otitis media)
• Multiple sclerosis
• Neoplasms near the facial nerve

Although a diagnosis of Bell’s palsy is often clinical and does not require extensive investigations, further testing may be warranted in certain cases, particularly if the presentation is atypical or if recovery is delayed. Investigations may include:

1. Blood Tests: As a screening test to detect systemic conditions (e.g. Lyme disease or sarcoidosis).
2. Electromyography (EMG): The test provides an electrical assessment of the facial muscles and the facial nerve. It can aid in the determination of the extent of nerve involvement and in predicting prognosis.
3. Magnetic Resonance Imaging (MRI) or Computed Tomography (CT): In order to eliminate structural causes, e.g. of brain tumours, demyelinating diseases such as multiple sclerosis, or a stroke that has occurred in the recent past, MRI or CT could be employed.
4. Lumbar Puncture (Spinal Tap): This is sometimes done when suspected infections (e.g. meningitis or neuroborreliosis) or inflammatory conditions (e.g. sarcoidosis) are suspected.

What are the Treatment Options for Bell’s Palsy?

Although most cases of Bell’s palsy resolve independently and without any medical assistance, medical experts can prescribe some forms of treatment that can help with the symptoms, protect the affected structures.

Treatment options for Bell’s palsy are:

1. Ocular Protection and Eye Care

• Proper eye care is a critical component of Bell’s palsy management, particularly when incomplete eyelid closure is present.
• Lubricating eye drops, such as artificial tears, are prescribed to relieve dryness and prevent corneal irritation.
• In case the eyelid does not perfectly cover the eye, then patching or a moisture chamber could be needed to protect the eye against environmental allergens, dehydration, and injury.
• This primary prophylaxis is indispensable to minimise the chances of corneal ulceration that will bring severe eye-related issues in case of non-treatment.

2. Oral Corticosteroids

• Oral corticosteroids are still the mainstay of pharmacological treatment, namely prednisolone.
• These medications help to reduce inflammation and oedema of the facial nerve, particularly where it traverses the bony fallopian canal.
• There are clinical indications that an early start, in-ideally within 48 hours of the starting symptom, significantly enhances outcomes and often produces better and more complete recovery of facial functionality.

3. Antiviral Therapy

Although the evidence remains inconclusive, antiviral agents (e.g., acyclovir or valaciclovir) may be considered in selected cases:

• These prescriptions are sometimes done when there is suspicion of a viral causative agent, and this includes the herpes simplex virus (HSV).
• They are usually reserved for serious presentations and are usually used in combination with corticosteroids to have the best effect, as there is no supportive evidence of clinical value that includes the use of antivirals as sole therapy in the majority of the studies.

4. Electrical Stimulation

• Some clinicians advocate the use of electrical nerve stimulation to maintain muscle tone and prevent atrophy.
• Nevertheless, there is no evidence on the therapeutic benefit in long-term functional outcomes of this modality.
• As such, its routine use remains controversial and not widely recommended in evidence-based guidelines.

5. Surgical Interventions for Refractory Cases

• In rare instances where facial paralysis persists beyond the expected recovery period, functional facial plastic surgery may be indicated.
• Surgical techniques can address facial asymmetry, restore facial muscle tone, and facilitate eyelid closure to enhance both function and appearance.
• These interventions are typically reserved for chronic or incomplete recovery and require a multidisciplinary approach involving neurologists, ophthalmologists, and plastic surgeons.

FAQs About Bell’s Palsy

1. How long does Bell’s palsy last?

Bell’s palsy typically begins to improve within two to three weeks, with most individuals recovering fully within three to six months. A minority may experience longer or incomplete recovery. 

2. Is Bell’s palsy a stroke?

No, this is not a stroke. Bell’s palsy is a result of inflammation of the facial nerve that produces the isolated facial weakness, unlike a stroke that affects the brain tissue and produces more wide-ranging neurological impairments. 

3. Is Bell’s palsy permanent?

Most cases are transient; most of the sufferers achieve full recovery. However, in a minority, facial weakness may persist, resulting in lasting impairment.

4. What are the risk factors for Bell’s palsy?

Risk factors are diabetes, pregnancy, preeclampsia, obesity, recent upper-respiratory infection, high blood pressure and perhaps the preceding dental procedures.

Conclusion

Bell’s palsy should be considered when a patient presents with sudden facial weakness, asymmetry, or difficulty closing one eye. Prompt recognition and appropriate management are essential to prevent complications and to promote optimal nerve recovery and facial function. 

If symptoms persist or worsen, urgent medical evaluation is crucial to rule out other neurological conditions and to guide treatment. With expertly curated video lectures, detailed revision notes, and high-yield study material, DocTutorials is a trusted platform for mastering clinical conditions like Bell’s palsy.

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