What is Bell's Palsy?
Bell’s Palsy was best characterized by Dr. Bell. However, it has been described for centuries before that.
Bell’s palsy is usually a diagnosis of exclusion, meaning that this is diagnosed once other causes such as autoimmune, trauma, iatrogenic etiologies, for example, have been eliminated. It is therefore also referred to as “Idiopathic Facial Paralysis”. Bell’s palsy is characterized by rapid onset, lower motor neuron facial deficit, and can be unilateral, partial or complete paralysis of the face.
Although the exact cause of Bell’s palsy is unclear, it has been hypothesized that it is due to a viral infection which causes inflammation, swelling, and damage to the facial nerve.
This disorder occurs equally in males and females, with a slightly higher occurrence in men >40 years old and women <20 years old. The incidence in the United States ranges from 25-30 affected per 100,000 individuals. Roughly 70% of patients with Bell’s Palsy will present with complete paralysis and 30% will present with incomplete paralysis.
What are the symptoms of Bell's Palsy?
- Sudden onset facial weakness or immobility that can progress rapidly to full paralysis over 72 hours.
- Facial droop with “stroke-like” appearance
- Inability to close the eye
- Sensitivity to loud sounds
- Change in facial sensation
- Neck or periauricular pain
- Unpleasant or strange taste sensations which occur during eating
- Excess tearing or tears running down the cheek
If you notice any sudden-onset asymmetry in your face, please seek immediate medical attention.
Symptoms of a stroke vs. Bell’s Palsy
The clinical presentation of Bell’s Palsy and a stroke (also known as a CVA or cerebrovascular accident) can closely mimic one another. In Bell’s Palsy, viruses long laying dormant in the facial nerve nucleus, suddenly activate when the body’s immune surveillance system drops below a certain level of regulation. Viral reactivation leads to multiplication the virions and invasion into nearby tissues. The immune system rapidly identifies this reactivation, and quickly mobilizes a humoral and cell-mediated response. This aggressive immune system response causes swelling, inflammation, and significant damage to the viruses and nearby cells, including the neurons, leading to dysfunction and facial nerve paralysis. The use of steroids, an immune suppressant, can limit the damage done by the immune system, and preserve as much facial nerve function as possible. The facial nerve can then recover and repair itself. With Bell’s Palsy, only the facial nerve is involved, and no other nerves or brain tissue is damaged. During a stoke, either due to a blood clot (ischemic) or active bleeding in the brain (hemorrhagic), blood supply to a part of the brain is interrupted and many of the brain cells in the affected area die due to oxygen starvation. While so called mini-strokes (often related to high blood pressure) may affect only a small area of the brain, such as the facial nerve center (nucleus), strokes more frequently affect multiple brain regions, and cause either difficulty with speaking, swallowing, hearing, blindness, incontinence, imbalance, arm or leg weakness, and numbness. In either case, it is recommended to present to your nearest emergency room as quickly as possible.
What causes Bell's Palsy?
Exact etiology remains unclear, but is thought to be viral etiology (herpes simplex type-1, chicken-pox virus, measles virus)
Risk factors for development: pregnancy, severe preeclampsia, diabetes, upper respiratory infections, hypertension, and obesity
How can Bell's Palsy be treated?
Acute
- Corticosteroids: If used shortly after onset, is highly likely to increase the probability of recovery of facial nerve weakness.
- Antiviral medication: can be added with corticosteroid therapy, and this may increase the likelihood of recovery (modest effect). It has not been shown to be effective when given alone.
- Surgical decompression may be offered to patients with >90% degeneration on electroneuronography testing and no voluntary electromyography motor unit potentials. Patients that presents within 14 days of symptom onset are considered surgical candidates.
- Even without treatment, most people will make a spontaneous recovery, but up to about 30% will have delayed or incomplete recovery.
- Facial re-training: the evidence is weak, but is thought to be able to improve the recovery of facial motor function scores and perhaps reduce the risk of synkinesis.
Based on the AAN evidence-based review on the treatment of Bell’s Palsy 2012.
https://www-ncbi-nlm-nih-gov.ucsf.idm.oclc.org/pubmed/28375913
Delayed Treatment for Chronic Facial Palsy
- Medical or surgical treatment for synkinesis (Botox or selective neurolysis)
- Facial reanimation procedures
- Facial re-training
Do exercises help with Bell’s Palsy?
Given that Bell’s Palsy is essentially self-limited and improves on its own, many efforts have been made to optimize or speed the recovery of patients with Bell’s Palsy. The interventions that have been tried include acupuncture, yoga, electrostimulation, and facial nerve rehabilitation (exercises), to name a few. While it is difficult to assert definitively that certain interventions are without value, very few of them have undergone rigorous study. Therefore, the only intervention that has scientifically proven value is the performance of facial nerve exercises and rehabilitation with an expert in neuromodulatory physical therapy. Shortened and chronically tonic muscles can be lengthened and relaxed with soft tissue mobilization and massage. The synkinetic (mass movement) associated with Bell’s Palsy can be improved with exercises designed to minimize parallel motions and create symmetry between the facial halves. The UCSF Facial Nerve Center offers close collaboration with facial nerve specialty trained physical therapists at multiple locations throughout San Francisco.
Is Bell’s Palsy Contagious?
Bell’s Palsy is not contagious in the vast majority of cases. As Bell’s Palsy is a diagnosis of exclusion (the diagnosis is made only after every other possible cause of facial paralysis has been evaluated and ruled out), it has to be assumed that the cause was a dormant virus whose reactivation is limited to a specific region of the brain. As this part of the brain is not able to be cultured or physically examined, the diagnosis is made by exclusion. In certain cases, facial nerve paralysis can be contagious, but then it is not Bell’s Palsy. Specifically, there is an entity called Ramsey-Hunt Syndrome (herpes zoster oticus), which is a herpes virus reactivation. This is essentially shingles of the outer ear and facial nerve, caused by reactivation of the chicken pox virus (varicella zoster). The rash presents as small pustules or fluid filled vesicles in and around the ear canal. This rash contains the chicken pox virus and is contagious.
Can you get Bell’s Palsy twice?
Typically, one cannot get Bell’s Palsy twice. The classic presentation of Bell’s Palsy occurs after the age of 40, when the immune system levels of antibodies and white blood cells combatting either the measles or chicken pox virus drops below a threshold of containment. The reactivation of these viruses laying dormant in the facial nerve nucleus in the brain, acts like a booster shot, and should provide enough support for the immune system to prevent another outbreak of the virus for the rest of your life. However, in the setting of immune suppression, such as with organ transplantation, certain bone marrow diseases, and/or diabetes, it is possible that the immune system function can be impaired and recurrent Bell’s Palsy is possible. Moreover, other causes of facial nerve dysfunction, such as a vascular malformation around the facial nerve, or a narrow bony canal through which the facial nerve travels, to name a few causes, can also mimic Bell’s Palsy and cause recurrence.
References
- Holland NJ and Bernstein JM. Bell’s Palsy. Clinical Evidence 2014;04:1204-23
- Vakharia Kavita andVakharia Kalpesh. Bell’s palsy. Facial Plastic Surgery Clinics of North America. 2016 Feb. 24(1):1-10.
- Baugh RF, Basura GJ, Ishii LE et al. Clinical practice guideline: Bell’s palsy. Otolaryngol Head Neck Surg, 2013 (149):S1-27
- Eviston TJ, Croxson GR, Kennedy PGE, Hadlock T, Krishnan AV. Bell’s Palsy: aetiology, clinical features and multidisciplinary care. 2015 Apr; 86:1356-1361