The facial nerve is the important cranial nerve that brings motor control to the face. These nerves are paired and arise from the brainstem, run through the skull base, pass immediately adjacent to the inner ear, swing through the middle ear and mastoid bone and exit near the jaw joint to branch out to all the muscles of the face. The facial nerve allows you to wink, close your eye, manage food in your mouth, whistle and smile. It is of utmost importance in the protection and moisturization of the cornea of the eye and problems can lead to permanent visual changes. Additionally, the facial nerve carries nerve impulses to the lacrimal or tear glands, the saliva glands, and the muscles of a small bone in the middle of the ear called the stapes. The facial nerve also transmits taste sensations from the tongue facial nerve problems can cause facial twitching, spasm or weakness that can range from a subtle problem to complete paralysis. Weakness/paralysis of the facial nerve may cause disfiguration and significant medical issues. Facial nerve disorders may be caused by many different conditions, including Bell's palsy, viral and bacterial infections, trauma to the skull or temporal bone, tumors of the facial nerve or its surrounding structures, surgical injury from ear, cosmetic or brain surgery to name a few.
Facial nerve symptoms require urgent evaluation. Multiple tests are usually required to evaluate the cause and extent of the problem and include an audiogram, CT, MRI, electric testing of the facial nerve and balance tests. Medical therapy can help reduce inflammation in or around the nerve but many conditions require surgical intervention. Early diagnosis and treatment can help to prevent more permanent damage to the nerve.
Bell's palsy is a form of facial paralysis resulting from inflammation of the facial nerve. Bell's palsy is named after Sir Charles Bell, a 19th century Scottish surgeon who was the first to describe the condition. The disorder is the most common cause of facial paralysis. Generally, Bell's palsy affects only one side of the face, however, in rare cases, it can affect both sides. The facial nerve becomes swollen, inflamed, or compressed, resulting in facial weakness or paralysis. Exactly what causes this damage, is still unknown. Many researchers believe that a viral infection such as the common cold sore virus - herpes simplex - causes the disorder. Many patients with the condition have had a viral upper respiratory ailments such as the flu or a cold before the onset of the facial symptoms. Bell's palsy afflicts approximately 40,000 Americans each year. It affects men and women equally and can occur at any age, but it is less common before age 15 or after age 60. It disproportionately affects pregnant women and people who have diabetes.
Bell's palsy can vary from person to person and range in severity from mild weakness to total paralysis. Symptoms may include weakness, or paralysis on one or both sides of the face, drooping of the eyelid and corner of the mouth, drooling, dryness of the eye or mouth, impairment of taste, and excessive tearing in one eye. Most often these symptoms begin suddenly and reach their peak within 48 hours. Other symptoms may include pain or discomfort around the jaw and behind the ear, tinnitus, headache, loss of taste, hypersensitivity to sound on the affected side, impaired speech, and difficulty eating or drinking.
A diagnosis of Bell's palsy is made based on clinical exam and by ruling out other possible causes of facial paralysis. There is no specific laboratory test to confirm the diagnosis. An audiogram is required.
Electrical tests called electromyography (EMG) and electroneurography (ENOG) can determine the severity and the extent of nerve involvement. A magnetic resonance imaging (MRI) ) scan can eliminate other causes of facial paralysis.
The treatment of Bell's palsy is varied. Some cases are mild and do not require treatment as the symptoms usually subside on their own within 2 weeks. For others, treatment may include medications and other therapeutic options. Steroids are an effective treatment for Bell's palsy. Prednisone is the most commonly used medication in the treatment of Bell’s palsy. It is effective in improving facial function by limiting or reducing damage to the nerve. Antiviral drugs are frequently used. An important factor in treatment is eye protection. Bell's palsy can interrupt the eyelid's natural blinking ability, leaving the eye exposed to irritation and drying. Therefore, keeping the eye moist and protecting the eye from debris and injury, especially at night, is important. Lubricating eye drops, such as artificial tears or eye ointments or gels, and eye patches are effective. Physical therapy to stimulate the facial nerve and help maintain muscle tone may be beneficial to some. Facial massage and exercises may help prevent permanent contractures (shrinkage or shortening of muscles) of the paralyzed muscles before recovery takes place. Electrical stimulation may help nerve regrowth.
The prognosis for individuals with Bell's palsy is generally very good. The extent of nerve damage determines the extent of recovery. Improvement is gradual and recovery times vary. Most individuals begin to get better within 2 weeks after the initial onset of symptoms and most recover completely, returning to normal function within 3 to 6 months. For some, however, the symptoms may last longer. In a few cases, the symptoms may never completely disappear. Early evaluation is therefore essential if the face becomes totally paralyzed. Facial nerve decompression is a surgical treatment for Bell's palsy to relieve pressure on the compressed nerve. The surgery is sometimes considered in severe cases of complete facial paralysis that has occurred within 2 weeks of onset. Careful electrical testing of the facial nerve is undertaken before considering surgery. Electrical testing is performed to predict the prognosis for recovery, and if poor, surgical decompression can be considered.
