BELL'S PALSY: SYMPTOMS, CAUSES AND TREATMENT - NEUROPSYCHOLOGY - 2025

The Bell 's palsy is a neurological disorder that affects the facial muscles, causing changes aesthetic, functional and psychosocial level (Benitez et to the., 2016).

This pathology constitutes the most common type of facial paralysis and is also called peripheral facial paralysis (León-Arcila et al., 2013).

Bell's palsy is caused by the presence of different damages or injuries to the facial nerves (cranial nerve VII) (National Institute of Neurological Disorders and Stroke, 2010).

Although it is a disorder that can occur in any age group, the exact etiological causes are unknown. However, in some cases traumatic or viral causes can be identified (León-Arcila et al., 2013).

Generally, the clinical course of Bell's palsy is temporary. In most cases, signs and symptoms begin to disappear a few weeks later (Mayo Clinic, 2014).

Features of Bell's palsy

At the beginning of the 19th century, a Scottish surgeon named Charles Bell first described an alteration that consisted of complete facial paralysis resulting from a traumatic event in the area of ​​the stylomastoid foramen, through which the facial nerve runs (León-Arcila et al.., 2013).

This medical condition was called Bell's palsy and occurs as a consequence of an irruption of the facial nerve function (National Institute of Neurological Disorders and Stroke, 2010).

The facial nerves or the VIII cranial nerve, is a structure that contains the nerve fibers that are responsible for controlling a good part of the functions of the facial area (Devéze et al., 2013).

Specifically, the facial nerve performs various motor functions of the muscles of facial mimicry, sensory in the external auditory canal, taste in the anterior portion of the tongue and some parasympathetic vegetative functions that control the secretions of the lacrimal and nasal glands. submandibular and sublingual (Devéze et al., 2013).

The VII cranial nerve is a paired structure that passes through a bony canal in the skull, below the ear area, towards the facial muscles (National Institute of Neurological Disorders and Stroke, 2010).

When this nerve structure is damaged, injured or inflamed, the muscles that control facial expression can become weak or paralyzed (American Academy of Ophthalmology, 2016).

In Bell's palsy, there is a sudden decrease or absence of mobility of the innervated muscles controlled by the facial nerve. Thus, it is possible to observe in the affected person that half of her face is paralyzed or "fallen" and she can only smile using one side of her face, close one eye, etc. (American Academy of Ophthalmology, 2016).

Therefore, affected people usually present various deficits in facial muscle functions and facial expression, such as the inability to close their eyes, smile, frown, raise eyebrows, speak and / or eat (Benítez et al.., 2016).

Statistics

Bell's palsy is one of the most frequent neurological disorders, being the main cause of facial paralysis (León-Arcila et al., 2013).

Thus, it has been observed that Bell's palsy is a neurological disorder that affects around 40,000 people each year in the United States (National Institute of Neurological Disorders and Stroke, 2010).

Worldwide, it is estimated that the incidence of Bell's palsy is approximately 70 cases per 6,000 inhabitants (Benítez et al., 2016).

This medical condition can occur in men and women and in any age group, however, it is less prevalent in the stages of life before 15 years of age and after 60 (National Institute of Neurological Disorders and Stroke, 2010).

In addition, a series of risk factors have been identified that significantly increase its occurrence, among them are pregnancy, diabetes, or some respiratory diseases (National Institute of Neurological Disorders and Stroke, 2010).

Signs and symptoms

Easy nerves have very diverse and complex functions, due to this the presence of a lesion in this structure can generate various alterations (National Institute of Neurological Disorders and Stroke, 2010).

Therefore, the signs and symptoms of this pathology can fluctuate depending on the severity and the person affected (National Institute of Neurological Disorders and Stroke, 2010).

The most characteristic symptoms of Bell's palsy usually affect one side of the face, which is why bilateral cases of facial paralysis rarely occur (American Academy of Ophthalmology, 2016).

In general, the clinical course of Bell's palsy usually presents suddenly and usually includes some of the following medical conditions (Mayo Clinic, 2014):

• Weakness of the facial muscles.
• Facial paralysis.
• Difficulty emitting facial expressions.
• Jaw pain or pain in the region after the pinna.
• Increased sensitivity to sound.
• Decreased effectiveness of the sense of taste.
• Recurring headache.
• Excessive tearing or dry eyes.

In addition, Bell's palsy is an alteration with an important functional and psychological effect, since it can have a great negative impact on patients and on their psychosocial environment (León-Arcila et al., 2013).

Its permanent?

The duration of facial paralysis is variable. According to the different classifications of this pathology in the medical literature, we can divide this type of condition into transitory and permanent (Benítez et al., 2016).

Bell's palsy is one of the types of temporary facial palsy (Benítez et al., 2016). In approximately 80% of cases, symptoms resolve in about three months, while many others begin to disappear in just two weeks (Clevelan Clinic, 2016).

Causes

This type of facial paralysis occurs when the nerves of cranial nerve VII are inflamed, compressed, or injured, leading to the development of facial paralysis or weakness (National Institute of Neurological Disorders and Stroke, 2010).

Despite this, the etiological cause of nerve damage in Bell's palsy is unknown (National Institute of Neurological Disorders and Stroke, 2010).

Specifically, more than 80% of Bell's palsy cases are classified as idiopathic (León-Arcila et al., 2013), a term used to designate diseases that erupt spontaneously and do not present a clearly defined cause.

Despite this, there is another percentage of cases in which the clinical course of Bell's palsy is associated with the presence of other types of pathological agents, such as the herpes simplex virus and varicella zoster (León-Arcila et al., 2013).

In addition, other cases resulting from infectious processes, genetic alterations, hormonal variations or traumatic events have also been identified (León-Arcila et al., 2013).

The etiological causes of facial paralysis are multiple and can be classified as congenital or acquired (Benítez et al., 2016).

Congenital-type easy paralyzes may result from the presence of congenital trauma, Moebious syndrome, or mandibular division, although they may also have no known cause. While acquired-type facial paralyzes usually result from a traumatic event or a viral inflammatory process (Benítez et al., 2016).

In addition to the conditions mentioned above, there are several cases in which the probability of suffering from Bell's palsy is higher than that of the general population (Mayo Clinic, 2014):

• Pregnant women: during the third trimester or in the first days postpartum.
• Have an upper respiratory infection, such as the flu or the common cold.
• Having diabetes
• Family history compatible with the presence of recurrent Bell's palsy.

Diagnosis

There is no specific laboratory test or analysis that is used to confirm the presence or diagnosis of Bell's palsy (National Institute of Neurological Disorders and Stroke, 2010).

Instead, this type of pathology of neurological origin is diagnosed based on the clinical presentation, that is, a detailed physical examination is carried out in which it should be observed: inability to perform movements or facial expressions, facial weakness, etc. (National Institute of Neurological Disorders and Stroke, 2010).

It is necessary to exclude other medical causes of facial paralysis such as temporal bone bills, acoustic neuromas, auditory tumors (León-Arcila et al., 2013), strokes and other pathologies or neurological conditions (American Academy of Ophthalmology, 2016).

Therefore, several complementary tests are usually used to confirm the presence of Bel's palsy (León-Arcila et al., 2013).

Specifically, neurophysiological evaluation is one of the most widely used methods to determine the degree of nerve degeneration and to predict the recovery of facial function.

Electro neurography is one of them, it allows to quantitatively and objectively assess the presence of a compromise in the facial nerve and also allows to establish an approximate recovery prognosis (León-Arcila et al., 2013).

In addition to this, other techniques used in the evaluation of Bell's palsy are electromyography (EMG), magnetic resonance imaging (MRI) or computed tomography (CT) (National Institute of Neurological Disorders and Stroke, 2010).

Treatment for Bell's palsy

Once the diagnosis of Bell's palsy is made, it is essential to start treatment immediately with the aim that recovery is complete and in the shortest possible time (León-Arcila et al., 2013).

This type of pathology can affect each person differently, in milder cases it is not necessary to use a specific treatment since the symptoms resolve spontaneously in a short time, however, there are other more serious cases.

Although there is no standard cure or treatment for Bell's palsy, the most important goal is to treat or eliminate the source of neurological damage (National Institute of Neurological Disorders and Stroke, 2010).

In some cases, medical specialists begin treatment with corticosteroids or antiviral drugs within three to four days after the onset of facial paralysis (Cleveland Clinic, 2015).

Some recent research has shown that steroids and antiviral medications such as acyclovir are an effective therapeutic option for Bell's palsy (National Institute of Neurological Disorders and Stroke, 2010).

In addition, the anti-inflammatory drug known as prednisone, is often used to improve facial function and reduce the possible inflammation of nerve areas (National Institute of Neurological Disorders and Stroke, 2010).

On the other hand, the therapeutic option based on surgical procedures is only considered as the last option when there is total facial paralysis, without response to drugs (Cleveland Clinic, 2015).

In addition to these factors, it will also be important to take into account the possible medical complications derived from facial paralysis, such as temporary or permanent hearing impairment and eye irritation or dryness (Cleveland Clinic, 2015).

Bell's palsy can prevent blinking in many cases, so the eye can be permanently exposed directly to the external environment. Thus, it is important to keep the eye hydrated and protected from possible injury. Medical specialists often prescribe the use of artificial tears, eye gels or patches (National Institute of Neurological Disorders and Stroke, 2010).

On the other hand, the use of physical therapy to help maintain muscle tone in the facial area is beneficial in many affected. There are facial exercises that can prevent the development of permanent contractures (National Institute of Neurological Disorders and Stroke, 2010).

In addition, massage or the application of moist heat can help reduce localized pain (National Institute of Neurological Disorders and Stroke, 2010).

These and other therapeutic measures used in Bell's palsy must be prescribed and implemented by the medical specialists in each area.

References

1. AAO. (2016). Diagnosis of Bell's Palsy. Obtained from the American Academy of Ophthalmology.
2. Benítez, S., Danilla, S., Troncoso, E., Moya, A., & Mahn, J. (2016). Comprehensive Management of Facial Paralysis. Rev Med Cin Condes, 27 (1), 22-28.
3. Cleveland Clinic. (2016). Bell's Palsy. Obtained from Cleveland Clinic.
4. khan, A. (2015). What Is Bell's Palsy? Obtained from Healthline.
5. León-Arcila, M., Benzur-Alalus, D., & Alvarez-Jaramillo, J. (2013). Bell's palsy, case report. Rev Esp Cir Maxilofac., 35 (4), 162-166.
6. Mayo Clinic. (2014). Bell's palsy. Obtained from Mayo Clinic.
7. NIH. (2010). Bell's palsy. Obtained from National Institute of Neurological Disorders and Stroke.