What is Bell Palsy?
Bell’s palsy is the most frequently encountered type of facial paralysis that affects the seventh cranial nerve, also known as the facial nerve. The onset of this condition is generally fast and it affects only one side of the face. Doctors usually diagnose it based on a physical exam, excluding other possible causes.
The facial nerve travels along a path inside and outside the skull, splitting into several branches. This nerve is complex, as it controls different tasks such as the movement of facial muscles, the production of tears and saliva, and even the sense of taste for the front part of the tongue. It’s particularly important to check the strength of the forehead muscles when diagnosing Bell’s palsy because if these muscles aren’t affected, the cause could lie somewhere in the central nervous system.
Though there has been debate about the effectiveness of antiviral therapy, the usual treatment involves a combination of steroid and antiviral medication.
Bell’s palsy commonly causes one-sided facial paralysis. Data show that people with diabetes, as well as pregnant women, have a higher chance of experiencing Bell’s palsy.
What Causes Bell Palsy?
Bell’s Palsy is a medical condition that, by definition, has no known cause. However, research has shown that it can be linked to several different factors. These include viral illnesses like herpes simplex virus, varicella-zoster virus, and the Epstein-Barr virus. There can be instances where a health care provider may, perhaps mistakenly, diagnose a patient with Bell’s Palsy, even when a possible cause could be identified, for example, conditions like Ramsay-Hunt syndrome and Lyme disease.
While there can be a range of causes, like unknown factors, injury, tumours, inborn deformities and immune system reactions, roughly 70% of all cases of facial nerve paralyses are categorized as Bell’s Palsy.
Risk Factors and Frequency for Bell Palsy
Bell’s palsy, a condition that causes temporary weakness or paralysis of the facial muscles, has an annual occurrence rate of 15 to 20 cases per 100,000 people, adding up to around 40,000 new cases each year. In terms of individual risk, approximately 1 in 60 people will experience Bell’s palsy in their lifetime.
While it can reoccur in 8% to 12% of people, the good news is that around 70% of individuals with Bell’s palsy will recover completely even without treatment.
Anyone can get Bell’s palsy as it does not favor any particular gender, race, or age group. However, it’s often seen in people in their middle and later stages of life, with the most common onset age being 40. Some factors that may increase one’s risk of developing Bell’s palsy include diabetes, pregnancy, preeclampsia, obesity, and high blood pressure.
- Annual incidence of Bell’s palsy is 15 to 20 cases per 100,000 people, tallying up to about 40,000 new cases each year.
- Lifetime risk of getting Bell’s palsy is 1 in 60.
- Reoccurrence of Bell’s palsy happens in 8% to 12% of cases.
- Even without treatment, 70% of people recover completely.
- Bell’s palsy can happen to anyone, regardless of gender or race.
- It is more common in middle and old age, with the average onset age at 40.
- Risks may increase if you have diabetes, are pregnant, have preeclampsia, are obese, or have high blood pressure.
Signs and Symptoms of Bell Palsy
Patients suffering from this condition often experience rapidly worsening symptoms within a day to a week, peaking in severity after about 72 hours. Most notably, they may have partial or total weakness on one side of their face. This facial weakness includes areas such as the eyebrows, forehead and corners of the mouth. In some cases, patients might not even be able to close the eyelid or lip on the affected side.
The central symptom during a physical examination is partial or complete forehead weakness. If strength in the forehead is maintained, it could indicate a central cause that needs further investigation. Patients also might report differences in taste, sensitivity to sound, ear pain, and changes in tearing and salivation.
When looking specifically at the eyes, several other symptoms might be noted:
- Exposure of the cornea (front surface of the eye)
- Lagophthalmos (inability to close the eye)
- Drooping of the brow
- Turned-out lower eyelid (paralytic ectropion)
- Retraction of the upper eyelid
- Decreased tear output
- Loss of the nasolabial fold (lines from the nose to the mouth)
Testing for Bell Palsy
When it comes to evaluating patients, especially those possibly dealing with Bell’s palsy, doctors primarily rely on the patient’s history and a physical examination. They may use something known as the House-Brackmann Facial Nerve Grading System to gauge the severity of the facial nerve weakness. This system gives ratings from I (no weakness at all) to VI (complete facial weakness).
In cases where Bell’s palsy fits the patient’s symptoms, doctors usually do not need to order laboratory tests or screening. But, unusual features may require additional testing to rule out any disease rooted in the central nerve system.
Concerning Lyme disease, tests primarily depend on whether the patient may have been exposed to tick-borne illnesses. Routine Lyme disease testing is not generally recommended unless there are other symptoms like a history of tick bites, skin rashes, or arthritis. Even though the optimal timing for Lyme disease imaging isn’t universally agreed upon, most experts suggest waiting until after two months of facial palsy without any improvement.
Importantly, doctors do not test for diabetes as facial nerve palsy doesn’t fall under diabetic neuropathy. Instead, they use magnetic resonance imaging (MRI) as the preferred imaging method. MRIs are useful in identifying facial nerve inflammation and ruling out conditions such as tumor growths or abnormal blood vessels.
In Bell’s palsy cases that are severe, nerve conduction tests and electromyography (EMG), which measures muscle response, may be implemented to help predict outcomes. The EMG test is used in recording the difference in potentials generated by the facial muscles on both sides. If hearing loss is suspected, auditory evoked potentials and audiography are typically performed. Additional tests may include checks for saliva flow, tear function, and nerve excitability.
In summary, diagnosing Bell’s palsy involves the use of a grading system. This system measures the degree of dysfunction ranging from minor to severe.
Treatment Options for Bell Palsy
While some people naturally recover from certain conditions without treatment, this isn’t always the case. Therefore, the need for treatment can sometimes be a grey area.
For example, a common treatment method involves corticosteroids, a type of medication often given in a daily dosage of 60 to 80 mg for about a week. Research suggests that combining corticosteroids with antiviral drugs may improve patient outcomes compared to solely using corticosteroids. But a 2009 analysis found that corticosteroids on their own were valuable in treating Bell’s palsy and adding antiviral drugs didn’t make a significant difference.
In cases where there’s severe facial nerve palsy, a combination of steroids and antivirals can be considered. These two drugs don’t typically lead to additional side effects compared to either placebo or corticosteroids. Patients should also be given advice on keeping their eye moist and using an eye patch at night to help protect the cornea.
Botulinum toxin, more commonly known as Botox, has been beneficial in reducing long-term issues related to this disorder. Surgery is usually only considered as a last resort, typically in chronic cases. Facial muscles generally stay functional for a number of years, and a variety of complex reconstructions are available if needed. There are also different methods to avoid eye dryness, like using eyelid weights or doing muscle transfers.
Decompressing the facial nerve, which involves reducing pressure on it, isn’t usually suggested as a treatment. Each case is evaluated individually to determine its potential usefulness. Past studies on this process have not been particularly high-quality. If there’s no improvement in a patient’s condition within a month, it’s generally recommended they see a specialist like a plastic surgeon, neurologist, or ear, nose and throat doctor to consider more aggressive treatments.
What else can Bell Palsy be?
When dealing with peripheral facial nerve palsy – or the sudden weakness of your facial muscles, there are several causes that need to be ruled out. Conditions such as Lyme disease and Ramsey-Hunt syndrome are usually the first causes to be considered. Certain uncommon conditions like tuberculosis, HIV, injury, sarcoidosis, vasculitis, and cancer can also result in facial palsy, and should therefore not be overlooked.
It is surprising but true that a high number of cases of facial palsy – about 10.8% – are misdiagnosed, even by experts. So, it’s always good to seek a comprehensive review.
If someone repeatedly experiences episodes of facial weakness, the rare and typically genetic Melkersson-Rosenthal syndrome should be considered. The syndrome often involves repeat facial palsy, swelling in the face and mouth, and a cracked tongue. This condition is usually diagnosed more in women than men.
What to expect with Bell Palsy
Bell palsy, a condition affecting the facial nerves, fully resolves without any treatment in 71% of cases. The use of corticosteroids, a type of medicine, has been found to increase the chance of better nerve recovery. However, the condition can come back, with studies reporting a recurrence rate of 12%. In fact, another study indicated that up to 10% of Bell palsy patients experienced a return of symptoms after an average of 10 years.
There are also certain risk factors tied to poorer outcomes in treating Bell palsy. These include complete facial paralysis, being 60 years old or older, and having reduced saliva production or taste on the same side as the paralysis. Also, the longer it takes to recover, the more likely it is that patients may develop lingering conditions or symptoms.
Possible Complications When Diagnosed with Bell Palsy
Bell palsy can lead to certain complications, which include:
- Dryness of the cornea, which can cause loss of vision
- Lasting damage to the facial nerve
- Abnormal growth of nerve fibers
Recovery from Bell Palsy
Regular check-ups are necessary for patients with Bell palsy to monitor their recovery. If less than 25% of the muscles are affected as shown by the EMG studies, then supportive care will suffice. If the paralysis is extreme, patients are advised to seek counseling.
Regarding rehabilitation, the advice given is somewhat limited due to the lack of high-quality studies. Still, various treatments are normally recommended at different recovery stages. These can range from electrotherapy, massage, mirror therapy, and facial exercises. However, personalized facial exercise programs and mirror therapy have shown the best results for early rehabilitation. Despite this, more research is required to establish standard treatment and rehabilitation guidelines.
