Introduction and Overview
Bell’s Palsy is a common form of temporary facial paralysis, affecting about one out of every 65 people, and about 50,000 North Americans each year.
This puzzling condition is the most common cause of facial paralysis. It almost always affects one side of the face only and results from a problem with one branch of the cranial nerve controlling the muscles of the face. With or without treatment, most people with this condition have a very good prognosis, as it will resolve on its own 80% to 90% of the time.
The exact cause of Bell’s Palsy, also known as idiopathic facial paralysis, is unknown, but most physicians suspect a viral infection, most likely Herpes Simplex or Herpes Zoster. Most people carry these viruses, but only some have an active version of it. Other viral illnesses, such as mumps or rubella may also trigger it.
The cranial nerves controlling facial movement are not only important for facial expressions like smiling and blinking, but also carry nerve impulses to the tear glands, the saliva glands, the muscles controlling the stapes in the middle ear and the transmission of taste sensations from the tongue.
Nearly everyone is susceptible to this partial paralysis, but for some reason it affects pregnant women in their third trimester, diabetics, the elderly, and those with an upper respiratory ailment such as influenza or a common cold more frequently than others. It is also seen in people with a compromised immune system.
Other possible causes include inflammation, autoimmune disorders or a decreased blood flow to the branch of the facial nerve affected.
One good warning sign of impending Bell’s Palsy is neck pain or pain in or behind the ear. Most people discover it upon awakening in the morning and may believe they have had a stroke, because of the unilateral affect on the face. The three major signs of stroke are:
- Unilateral paralysis of the facial muscles
- Inability to raise both arms above the head
- Inability to say a complete sentence
Bell’s Palsy mimics the first sign, but not the next two, so patients who can perform the second two without difficulty have most likely NOT had a stroke. A physician can do a more thorough exam and provide a more definite diagnosis, however, and should be consulted. A thorough case history and an examination of the ears, nose, throat and cranial nerves should be done, to rule out other brain injury.
Signs and Symptoms
Signs and symptoms of Bell’s palsy include:
- Acute onset and worsening over the first 48 hours
- Pain or aching of the ear or the area around the ear
- Weakness or paralysis of the facial muscles on one side
- Taste disturbances
- Hearing disturbances, especially hypersensitivity to sound
- Tingling or numbness of the cheek and mouth, with or without drooling
The main ocular findings include a lack of control over blinking and/or closing of the eye on the affected side, blurred vision, eye pain and a decrease in tear production. It is quite common for patients with this condition to be unable to completely close the affected eye, which has implications for longer-term damage if the eye is not protected adequately. In other cases, the lacrimal gland may produce too much moisture and the eyes can overflow.
Most patients just wait out the condition, as most cases will resolve on their own within the first two or three weeks, with complete resolution after three months.
The most important treatment is to make sure the affected eye is protected from dryness or other injury, because of the inability to completely close it. Other treatment is generally conservative. Antiviral therapy, with high-dose corticosteroids has been used in severe cases, but the benefits of treatment are not clear-cut.
Because the eye is susceptible to damage from dryness, which can cause corneal scarring and loss of vision, most treatment is aimed at protecting it, using topical drops and ointments to sustain lubrication, and possible taping of the eye closed, especially during the night, after application of ocular ointment or gel lubricants.
Other than protecting the eye, it is perhaps wise to do facial muscle exercises using passive range-of-motion and actively trying to smile, frown, blink, wrinkle the forehead and raise the eyebrows. Even if these can’t be adequately performed, maintaining the motions needed for them will help in the long term.
If the paralysis lasts longer than three months, surgical intervention with implanted weights in the eyelid to keep it closed will cut down on the amount of lubricants needed otherwise and improve cosmesis.
Bell’s Palsy is not itself considered to be a serious condition, because most cases resolve themselves fairly rapidly, usually between two and three weeks. It is only in those rare cases that the paralysis lasts longer than three months or so that other treatments or surgical intervention might be considered.
Most people who wake up to find one side of their face paralyzed may be excused for being fearful of more serious problems like stroke or lower-brain injury and a physician should be consulted in any case. An eyecare practitioner can advise patients on how to care for the affected eye, keep it protected and keep it moist. If ocular damage can be avoided, no other treatment is needed or recommended in most cases.