Facial nerve palsy (Bell’s palsy) is one of the most common temporary facial disorders, affecting thousands of people around the world every year. It usually appears suddenly and affects one side of the face, which can make it difficult to show normal facial expressions such as smiling or closing the eyes, which can cause anxiety and discomfort for sufferers.
Studies show that Bell’s palsy affects about 20 to 30 out of every 100,000 people annually and can occur at any age, but is more common in middle-aged adults. Although most cases are temporary and improve spontaneously within weeks, early recognition of symptoms and proper understanding of the condition help to effectively manage symptoms, accelerate recovery, and prevent potential complications.
What is the facial nerve?
The facial nerve, also known as the seventh cranial nerve and the seventh cranial nerve, is a nerve in the head that sends signals from the brain to parts of the face, and vice versa. There are two facial nerves, one on each side of the head. The facial nerve is the seventh pair of the 12 cranial nerves that make up the nervous system.
Facial nerves are constantly at work, responsible for many important functions that characterize us as humans, such as forming countless facial expressions, speaking, tasting, and producing tears.
What are the functions of the facial nerves?
The facial nerve is not a single-function nerve; it carries different types of nerve fibers, each with a specific role in the body.
- Motor functions: The facial nerve controls the movement of most facial muscles, so it is responsible for facial expressions such as smiling, frowning or closing the eyes.
- Sensory functions: Transmits the taste sensation from the front two-thirds of the tongue, and feeds some parts of the outer ear and eardrum.
- Parasympathetic functions: This fiber helps stimulate the salivary glands to produce saliva and the lacrimal glands to produce tears, keeping the mouth and eyes hydrated.
The facial nerve is essential for taste, movement, and sensation, as well as the secretion of tears and saliva.
What is Facial Nerve Palsy?
Bell’s palsy and facial palsy are all names for facial nerve paralysis, which is a paralysis affecting half of the face, often accompanied by mild pain, numbness, and loss of sensation in half of the face, as well as increased sensitivity to sound and changes in taste.
Facial nerve palsy is usually idiopathic, but a percentage of cases may be caused by the herpes virus in the stapedial ganglion of the facial nerve. It is a condition that affects only one side of the face; the muscles on one side of the face become temporarily weak or paralyzed, resulting in drooping or stiffness on that side.
Bell’s palsy is most common in people between the ages of 15 and 40. Most people recover spontaneously within one month of the nerve injury, but in 30% of cases, sufferers show delayed or incomplete recovery.
Causes of facial nerve palsy
The cause of this condition is still unknown. Still, it is believed to be caused by damage or inflammation to the facial nerve, which leads to swelling and enlargement, as the facial nerve passes through a narrow bony area inside the skull. As a result of its swelling, it is compressed, disrupting the nerve’s function.
Viral infections may play a role in facial nerve palsy. Herpesvirus 1 is responsible for a large number of cases, and there are some other viruses that have been linked to facial nerve palsy:
- rubella
- Mumps virus
- Influenza B
- Chickenpox and Herpes Zoster
- Epstein-Barr virus (EBV), which causes mononucleosis
- Cytomegalovirus
- Coxsackievirus hand, foot, and mouth disease virus
- Diabetes mellitus
- immunodeficiency
- Pregnancy
Symptoms and signs of Bell’s palsy
The most obvious sign of Bell’s palsy is the drooping of one side of the patient’s face and difficulty closing the eye on the affected side, as well as difficulty smiling and making other facial expressions. In rare cases, nerve paralysis can occur on both sides of the face. In addition to the difficulty in moving the facial muscles, some other symptoms can be observed in patients:
- Dry eyes and mouth
- Pain in the jaw or behind the ear, which often occurs before the onset of symptoms (1 to 4 days before the onset of symptoms)
- headache
- Impaired sense of taste
- Tinnitus
- Hypersensitivity to sounds, with sounds sounding much louder than usual in the days leading up to the onset of symptoms
- Difficulty speaking, eating, and drinking
Predisposing factors for facial nerve palsy
There are several factors that increase the likelihood of developing it, including:
- Pregnancy, especially during the last trimester or the first week after delivery
- Diabetes mellitus;studies have shown that diabetes mellitus is associated with a higher risk of developing this paralysis
- Some autoimmune diseases
- Cold sores
- High blood pressure
Diagnosis of facial nerve palsy
There is no specific laboratory test to diagnose it, but it is detected through what is called an exclusionary diagnosis, which means that doctors diagnose it only after all other possibilities have been ruled out. A complete physical examination and a thorough examination of the facial muscles is usually performed by trying all facial expressions, such as smiling.
Your doctor may order an electromyogram (EMG) to measure the electrical activity of the muscle. The doctor may also order an X-ray of the skull or an MRI to make sure there is no tumor or bone fracture pressing on the nerve.
Facial nerve palsy treatment
Most people with Bell’s palsy recover spontaneously without treatment. In some people, we may observe a longer recovery period and in some rare cases the symptoms are permanent, but improvement usually occurs within three weeks after the onset of symptoms.
There are some treatments that may help you heal faster, such as corticosteroids, which help reduce swelling and increase the likelihood of normalizing nerve function, thus reducing the duration of paralysis symptoms, noting that they work best if taken within 72 hours of the onset of symptoms.
Antiviral treatment may be needed if the symptoms are caused by herpesvirus 1 or shingles. If the paralysis prevents the eye from closing, the affected eye should be protected by using sterile eyedrops to keep it moist, and facial massages and simple movements help to activate the muscles and prevent stiffness, and may speed up recovery.
Surgical intervention for facial nerve palsy is not recommended unless symptoms persist for a long time or when complications arise.
Complications
Although most patients make a full recovery, some cases may experience complications, especially if treatment is delayed or if symptoms persist for a long time:
- Permanent damage to the facial nerve
- Partially or permanently weakened facial muscles
- Involuntary muscle contraction
- Partial or complete blindness of the unclosed eye due to excessive dryness and corneal scratching
The difference between facial nerve palsy and stroke
It is important to know the difference between the symptoms of facial nerve palsy and facial stroke. They are the two most common causes of facial muscle weakness, and while seventh nerve palsy is a non-emergency condition, stroke requires emergency care in a well-equipped hospital.
It is therefore important that any sudden weakness of the facial muscles be medically evaluated urgently to rule out that it is part of a stroke symptom, especially if it is accompanied by an inability to raise the arm or difficulty speaking.
In the case of facial nerve palsy, we notice the disappearance of forehead wrinkles on the affected side when raising the eyebrows, while in the case of stroke, forehead wrinkles are not lost on the affected side of the face, and the person is able to raise his eyebrows on the affected side due to the presence of dual nerve supply coming from the brain to these areas.
Living with Bell’s palsy
Bell’s palsy usually resolves gradually over time and does not leave serious or permanent complications in most patients. However, the recovery phase may take several weeks or months, making adherence to the treatment plan essential. It is important to take medications as instructed by your doctor, especially corticosteroids, which reduce inflammation and speed up healing.
Special attention should be paid to the eye on the affected side, as it may not close completely, exposing the cornea to dryness or ulceration. Using moisturizing drops during the day and eye ointment before bed will help protect the eye from irritation. In addition, some patients may be advised to resort to facial physiotherapy exercises to stimulate the muscles and maintain their elasticity. Following these simple guidelines can make living with Bell’s palsy less uncomfortable and safer until full recovery.
Finally, Bell’s palsy is a common facial nerve condition that affects the facial muscles, is often temporary, and gradually improves over time. However, early diagnosis and proper treatment accelerate recovery and minimize potential complications. Bimarestan Medical Center provides specialized and comprehensive care for facial nerve palsy patients, with experts in diagnosis, pharmacological and physical therapy, to ensure the safe and effective restoration of facial functions and improve patients’ quality of life.
Sources:
- Johns Hopkins Medicine. (n.d.). Bell’s Palsy
- WebMD. (2023, November 14). Bell’s palsy: Causes, symptoms, and treatment
- National Health Service. (n.d.). Bell’s palsy
