Bell's Palsy Health Article

Definition

Bell's palsy describes the acute onset of an unexplained weakness or paralysis of the muscles on one side of the face. Afflicted individuals may be unable to close the eye on the affected side of the face, and may also experience tearing, drooling, and hypersensitive hearing on the same side. The onset can be quite sudden, sometimes occurring overnight. The weakness and paralysis resolve completely in the majority of cases. Although it cannot be considered a serious condition from a health standpoint, it can cause extreme stress, embarrassment, and inconvenience for those affected.

Description

Bell's palsy has been described as a diagnosis of exclusion because several other disorders exhibit similar symptoms. Facial palsies have been linked to conditions such as Lyme disease, ear infection, meningitis, syphilis, German measles (rubella), mumps, chicken pox (varicella), and infection with Epstein-Barr virus (e.g., infectious mononucleosis). True Bell's palsy is an idiopathic facial palsy, meaning the root cause cannot be identified. Although Bell's palsy is not life-threatening, it can present symptoms similar to serious conditions such as stroke, ruptured aneurysm, or tumors.

Demographics

Every year, approximately 40,000–65,000 Americans are stricken with Bell's palsy. Worldwide, there is an annual incidence of 20–30 cases per 100,000 individuals. An individual can be affected at any age, but young and middle-aged adults are the most likely to be affected. It is unusual to see Bell's palsy in people less than 10 years old. Bell's palsy can affect either side of the face. Gender does not seem to factor into risk, though pregnant women and individuals with diabetes, influenza, a cold, or an upper respiratory infection seem to be at a greater risk.

In the large majority of cases (80–85%), the facial weakness or paralysis is temporary. However, individuals who experience complete paralysis seem to have a poorer recovery rate with only 60% returning to normal. Approximately 4–6% of all Bell's palsy cases result in permanent facial deformity, and another 10–15% experience permanent problems with spasms, twitching, or contracted muscles. Between 2% and 7.3% of individuals who have had Bell's palsy could experience a recurrence: on average, the first recurrence happens 9.8 years after the first episode; the second, 6.7 years later. One recurrence is very infrequent, and a second is extremely rare.

Causes and symptoms

The symptoms of Bell's palsy arise from an inflammation of the seventh cranial nerve, otherwise called the facial nerve. Each side of the face has a facial nerve that controls the muscles on that side of the face. Inflammation leads to the interference with conduction of nerve signals, and that in turn results in the loss of muscle control and tone.

Why the facial nerve becomes inflamed in Bell's palsy is a matter of considerable debate. Some evidence implicates the herpes simplex virus (HSV), which is responsible for cold sores and fever blisters. HSV infection has been suggested in up to 70% of Bell's palsy cases. Most people harbor this virus, although they may not exhibit symptoms. A number of other conditions have also been associated with the development of Bell's palsy, including facial or head injuries, headache, repeated middle ear infections, high blood pressure, diabetes, sarcoidosis, tumors, influenza, and other viral infections, as well as Lyme disease.

The major symptom of Bell's palsy is one-sided facial weakness or paralysis. Muscle control is either inadequate or completely missing. Patients frequently have difficulty shutting the affected eye and may not be able to close it at all.

Other symptoms can include pain in the jaw or behind the ear on the affected side, ringing in the ear, headache, decreased sense of taste, hypersensitivity to sound on the affected side, difficulty with speech, dizziness, and problems eating and drinking.