Bell’s Palsy - Symptoms, Diagnosis, and Treatment

What is Bell’s Palsy?

Bell's Palsy is the most common diagnosis of facial nerve palsy. This condition is frequently characterised by paralysis and muscular weakness of one-half of the facial muscles (rarely will it affect both sides at once). These changes can lead to further complications, such as damage to the eyes, speech difficulties and affected facial expression. In Australia, Bell's Palsy will approximately affect 11-40 per 100,000 people or roughly a yearly total of roughly 2,800-10,100. Despite a very rapid onset of symptoms, most people will also recover quickly. However, specific treatments can improve the rate of recovery and those experiencing persisting symptoms. Those who consult a GP earlier will also likely experience better outcomes.

Bell’s Palsy Symptoms

Symptoms of Bell's Palsy often start suddenly and will progressively worsen quickly within three to seven days. The severity of the symptoms can vary person-to-person. Whilst some people only experience some minor facial weakness, others can experience complete paralysis. Examples of common symptoms include [1]:

- Weakness and paralysis on one side of the face, which often results in facial drooping

- Numbness on affected side
- Difficulty with smiling, puffing cheeks or sealing lips
- Abnormal eye function (e.g. inability to fully close eyes, dryness, etc.)
- Unusually louder sounds on the affected side (also known as hyperacusis)
- Altered taste sensation
- Headaches
- Neck pain

Bell’s Palsy Causes

The causes of Bell's Palsy are typically idiopathic, which means that the cause is generally unknown. Most of the research seems to suggest that the condition occurs due to inflammation and swelling around the facial nerve (also known as Cranial Nerve VII [1]). These changes can disrupt the usual function of this nerve, such as facial expression, sensation, salivation, etc. It's important to consider that not all facial palsies are due to Bell's Palsy. Other conditions can present with similar symptoms (which is discussed in the Diagnosis section). The reason behind the inflammatory changes around the nerve is currently still being investigated. However, there have been links with viral infections and/or autoimmune responses [2]. Examples of viral causes that have been most closely linked to Bell's Palsy include:

- - Herpes Simplex Virus Type 1 (HSV-1) which can cause cold sores
  - Varicella-Zoster Virus (VSV) (more commonly known as chickenpox and shingles)
  - Epstein-Barr Virus
  - Usutu Virus

Additionally, ischaemia (restricted blood flow), extreme cold exposure and Guillian-Barré Syndrome [2] have also been speculated as potential causes.

Tests and Diagnosis

As numerous conditions share similar symptoms to Bell's Palsy, it's crucial to see your GP as soon as possible. A physical examination and specific tests will be ordered to assess for other conditions [3]. Examples of other conditions that doctors may check for includes:

- - Stroke
  - Multiple Sclerosis
  - Tumours
  - Mumps
  - Rubella
  - Lymphoma
  - Fractures
  - Nerve damage
  - Ear disorders

There is no gold standard test for diagnosing Bell's Palsy but rather by excluding other conditions. In some circumstances, your GP will refer for further assessments, such as an MRI, electromyography or electroneurography [4].

Is Bell’s Palsy Contagious?

Bell’s Palsy is not contagious and cannot be transmitted to other humans. However, viral infections that may be responsible for Bell’s Palsy (e.g. Herpes Simplex Virus Type 1, Varicella Zoster Virus, etc.) are highly contagious, especially during close and/or direct contact.

Bell’s Palsy Treatment

To fast-track recovery, doctors may prescribe Bell's Palsy medications such as corticosteroids and antiviral therapies. However, these are most effective within 72 hours after symptoms appear and warrants seeing a GP as soon as possible. Whilst most patients recover from Bell's Palsy; some people will experience lingering symptoms for prolonged periods. Doctors may recommend specific therapies and health services [1, 3]. Currently, not all treatments have been proven to be effective. As a result, referrals may be made on a case-by-case basis, depending on the types and severity of symptoms. Examples of these therapies and treatment include:

- - Dental care to manage the build of food on the affected side
  - Eye drops to prevent the eyes from drying out.
  - Protective eyewear (e.g. goggles, eye patch, etc.) to accumulation of debris and other substances
  - Pain relief medication
  - Physiotherapy for the prescription of Bell's Palsy exercises, electrotherapy and massage techniques to restore movement
  - Acupuncture for pain management and facial paresis treatment
  - Psychological support to manage any self-esteem or confidence issues
  - Speech pathology to help restore verbal impediments.
  - Referral to a surgeon, neurologist or otolaryngologist for those with chronic and persistent symptoms
  - Botox injections to restore muscle tone

Bell’s Palsy Recovery

The majority of those diagnosed with Bell's Palsy will recover spontaneously and without any additional treatment. Up to 71% of patients will report noticeable improvements in their symptoms within 3-4 weeks [3, 4]. However, there are specific characteristics which may result in slower recovery and poorer outcomes [1], including:

- - Those with intense pain
  - Diagnosis of other chronic conditions (e.g. high blood pressure, diabetes, etc.)
  - Significant deterioration of the facial nerve
  - Pregnant individuals
  - Being older than 60 years of age
  - More substantial facial paralysis

How long does Bell's Palsy last?

Up to 74% of those experiencing total facial paralysis and 90% of those with partial paralysis will completely recover within 6 months [3,4].

Does Bell's Palsy come back?

Recurrence of Bell’s Palsy is rare and recur between 7-12% of those diagnosed previously [5, 6, 7].

Complications

Although most cases of Bell's Palsy will ultimately resolve, others can be left with long-lasting disabilities. Prominent examples include ongoing paralysis or synkinesis (abnormal facial movements), which may require treatment [4]. If these symptoms continue to persist, they can lead to additional complications, such as:

- - Eye damage due to the inability to completely shut the eyelids
  - The build-up of plaque on the affected side due to reduced ability to move the mouth
  - Being self-conscious due to facial disfigurement
  - Degeneration of the facial nerve

Can Bell's Palsy cause a stroke?

Studies [8, 9] have linked a 2.02-2.38 times higher risk of experiencing a stroke in those previously diagnosed with Bell's Palsy than those who haven't.

Can Bell's Palsy affect speech?

Yes, damage to the facial nerve leads to facial drop. This impacts the ability to move the lips and control the muscle tone around the cheeks on the affected side. Without proper control of the mouth and jaw, the capacity to produce everyday speech is reduced.

References

1. Sarhan, F., Saif, A., & Saif, D. (2012). Bell's palsy: an overview. British Journal of Neuroscience Nursing, 8(4), 163-168.
2. Zhang, W., Xu, L., Luo, T., Wu, F., Zhao, B., & Li, X. (2019). The etiology of Bell’s palsy: a review. Journal of neurology, 1-10.
3. Phan, N. T., Panizza, B., & Wallwork, B. (2016). A general practice approach to Bell's palsy. Australian family physician, 45(11), 794-797.
4. Baugh, R. F., Basura, G. J., Ishii, L. E., Schwartz, S. R., Drumheller, C. M., Burkholder, R., ... & Vaughan, W. (2013). Clinical practice guideline: Bell’s palsy. Otolaryngology–Head and Neck Surgery, 149(3_suppl), S1-S27.
5. Swami, H., Dutta, A., & Nambiar, S. (2010). Recurrent Bell's palsy. Medical Journal, Armed Forces India, 66(1), 95.
6. Dong, S. H., Jung, A. R., Jung, J., Jung, S. Y., Byun, J. Y., Park, M. S., ... & Yeo, S. G. (2019). Recurrent Bell's palsy. Clinical Otolaryngology, 44(3), 305-312.
7. Cirpaciu, D., Goanta, C. M., & Cirpaciu, M. D. (2014). Recurrences of Bell's palsy. Journal of medicine and life, 7(Spec Iss 3), 68.
8. Lee, C. C., Su, Y. C., Chien, S. H., Ho, H. C., Hung, S. K., Lee, M. S., ... & Huang, Y. S. (2013). Increased stroke risk in Bell's palsy patients without steroid treatment. European journal of neurology, 20(4), 616-622.
9. Chiu, Y. N., Yen, M. F., Chen, L. S., & Pan, S. L. (2012). Increased risk of stroke after Bell's palsy: a population-based longitudinal follow-up study. Journal of Neurology, Neurosurgery & Psychiatry, 83(3), 341-343.

Bell’s Palsy – Symptoms, Diagnosis, and Treatment