Understanding a palsy

Print edition : February 02, 2002

Bell's palsy, a facial affliction caused by nerve damage, remains a physically and psychologically challenging experience for its victims.

TORAL J. agrees to speak only after draping a veil of black muslin over her face. Initially she is silent, embarrassed that her words slur, that she has to slip constantly a tissue under the veil to mop up saliva and that she has to lower and raise her eyelid manually to moisten her eye.

A victim of Bell's palsy, Toral J. is in her second week of recovery. Her doctor has assured her of almost complete recovery, but she is so traumatised by the temporary deformity this condition has imposed that she cannot think ahead. "I only pray that I shall wake tomorrow and I shall look normal," she says. For most people affected by Bell's palsy this would sound like a reasonable desire, especially because the affliction can strike overnight, as it did in Toral's case. "I went to bed fine and woke up in the morning looking as if some seismic activity had struck my face," she says.

Bell's palsy is a condition that affects the seventh cranial nerve (CN-VII) and causes the facial muscles to weaken or become paralysed. Only one side of the face is affected. Named after Sir Charles Bell, a Scottish surgeon who studied the nerve and its innervation of facial muscles 200 years ago, Bell's palsy is a condition that is not as uncommon as is generally believed. Statistics set its worldwide frequency at just over 0.02 per cent of the population, with geographical variations - that is, one for every 5,000 people over the course of a lifetime. The affliction affects about 40,000 Americans every year. The possibility of recurrence is believed to be as high as 10 to 20 per cent, but a lot more is to be learnt about this aspect of the condition.

The facial nerve has 7,000 individual nerve fibres, each carrying electrical impulses to a specific muscle.-

Dr. Nadir Bharucha, consulting neurophysician at Bombay Hospital, Mumbai, says that although he has no statistical evidence (little research has been done on Bell's palsy in the Indian context), he does see more patients now with the affliction than he used to earlier. He, however, believes that this does not necessarily mean that there is an increase in the incidence of the condition.

Dr. Roop Gursahani, consulting neurologist at the Hinduja Hospital, Mumbai, says that in his experience there is a seasonal rise in its incidence. "I see more cases during the monsoon and winter seasons, when usually virus-related illnesses are prevalent. It is associations like these that lead us to assume that Bell's palsy is caused by a virus," he says.

It is important to distinguish Bell's palsy from other types of facial paralysis. "There are many types of facial paralysis and many physical symptoms associated with facial paralysis. The cause of these could be related to anything. But Bell's palsy is specifically related to an affliction of CN-VII," says Dr. J.S. Sorabjee, consulting physician at Bombay Hospital.

The symptoms can vary in accordance with the degree of nerve damage and the location of the damage. The symptoms include muscle weakness or paralysis in which the wrinkles on the forehead disappear and the face assumes an overall droopy appearance. The patient finds it difficult, and in some cases impossible, to blink and experiences a running or a stuffy nose and difficulty in speech and in eating and drinking. He/she has hyperacusis or heightened sensitivity to sound, excess or reduced salivation accompanied by drooling, facial swelling, diminished or distorted taste, and pain in or near the ear. The eyes are especially affected. Closing of the eyes is difficult or impossible; there is a lack of tears or excessive tearing; and the tears usually fail to coat the cornea, thus causing the serious problem of dry eye. The lower eyelid droops and the eye's sensitivity to light becomes acute.

The good news is that the situation is temporary. Doctors say that recovery comes about in three months and that the recovery rate is excellent. "The fear of most patients, and especially of the older ones, is that they have had a stroke. I make it a point to reassure them that Bell's palsy is a mild condition in which the nerve has been blocked temporarily whereas a stroke is a serious occurrence in which an area of the brain has stopped receiving blood supply," explains Gursahani.

The bad news is that Bell's palsy cannot be prevented. "We just don't know enough about it," says Bharucha, who is one of India's most respected epidemiologists. The predisposing factors for Bell's palsy are not known. Stress and extremes of temperature are two factors cited most often, but the predominance of the former in everyday life means that just about anyone can be struck by this condition.

After leaving the brain, the facial nerve enters the bone of the ear in close association with the hearing and balance nerves.It divides into its main branches inside the parotid gland.These branches further divide into 7,000 nerve fibres, which reach into the face, the neck, the salivary glands and the outer ear.-

The rapidity with which the condition progresses is part of the horror that patients have to contend with. Most patients either wake up to find that they have Bell's palsy, or have symptoms such as a dry eye or a tingling feeling around their lips, which progress to classic Bell's palsy during the same day. Occasionally, the symptoms may take a few days to become recognisable as those of Bell's palsy. The degree of paralysis should peak within days of its onset.

Speaking of his own experience, Jim Mains, superintendent of the American School of Bombay, says: "Shampoo kept going in my eye when I was in the shower. My lips felt funny. First I thought it was a food allergy. Then I looked in the mirror and told my wife, 'I have Bell's palsy'. The reason I knew that was that I'd seen this happen to a friend. I did a further bit of self-diagnosis, rubbing and pulling my fingers, and said, 'No, I don't have a stroke. When you have Bell's palsy you have feeling but you have no control."' The doctor confirmed what Mains had suspected.

In most cases the diagnosis takes long. Typically, doctors first exclude other reasons for facial paralysis by means of blood tests, Magnetic Resonance Imaging (MRI) and Computer Axial Tomography (CAT) scans. Bharucha says: "At first it is differential diagnosis. We rule out the possibility of it being a stroke, and of the symptoms being caused by diabetes (diabetes can also affect CN-VII), middle ear infection and other infections, herpes zoster, head injury and trauma. Bell's palsy is really a diagnosis of exclusion." The etiology of Bell's palsy is still a matter of discussion. Viral and bacterial infections, as well as autoimmune disorders appear to be emerging as the most frequent common thread in the etiology of Bell's palsy.

Among viral infections, the most frequent cause is infection by the herpes virus Herpes Simplex-1 or HSV-1. Research since the 1970s shows that HSV-1 possibly accounts for 60 to 70 per cent of all Bell's palsy cases. Most people are exposed to the virus during childhood. Kissing between relatives, a practice common in some communities, is the most frequent source of exposure, but it is possible that the virus may also spread through sharing of towels, utensils and so on. The active virus is commonly associated with cold sores, but it often runs its course without causing any blisters. Blisters appear for only 15 per cent of the duration of the disease. This results in a large population of HSV-1 carriers who do not know that they have been exposed to the virus. HSV-1 is infectious for a short time following its incubation period. It then enters a dormant state and resides in the nerve tissue.

There are several triggers that can reactivate the dormant virus. Impaired immunity, whether temporary (owing to stress, extreme temperatures, lack of sleep, minor illnesses, physical trauma, upper respiratory infection, and so on) or long-term (owing to autoimmune syndromes, chronic disease and so on) is suspected to be the most likely trigger.

The reactivated virus usually affects the nerves on the skin. However, when the latent virus is reactivated at the facial nerve, the immune system begins to produce antibodies and causes an inflammation. If the location of the inflammation is within the small, bony tube called the fallopian canal, there is no room for the swelling to expand: the nerve itself becomes inflamed, or the inflammation within the canal exerts pressure on the nerve. Compressed inside its bony tube, the nerve stops transmitting signals to the muscles. The muscles, on receiving no signals to contract or relax, become temporarily weakened or paralysed. While this is the background of the onset of Bell's palsy, the immediate triggers for the reactivation of the virus have not been identified conclusively.

Bacterial triggers that could cause Bell's palsy are Lyme's disease (caused by the bite of the deer tick) and otitis media in which bacteria from some acute or chronic middle ear infection can invade the canal around the nerve through small portals. As with viruses, the presence of bacteria can evoke an inflammatory response and compress the nerve.

It is also suspected that the Human Immunodeficiency Virus (HIV) can cause facial paralysis and increase the chance of developing Bell's palsy. In the early stage of HIV infection, paralysis can be directly owing to the viral infection. In later stages, paralysis is more likely to be caused by the infections or tumours associated with severe immune deficiency.

THE first priority in the treatment for Bell's palsy is to eliminate any source of damage to the nerve as quickly as possible. Minor compression for a short period can result in mild and temporary damage. As time goes on, the damage to the nerve can also increase owing to constant or increasing compression. If the origin of the palsy is viral, both the virus and the inflammation are likely to run their natural course in a short period of time even without medication.

There is no firm proof that medication is beneficial in treating Bell's palsy, but a short course of steroids is standard therapy to lessen the inflammation. Bharucha says that anti-viral drugs are not that effective. For any medication to be effective, a minimum of seven days is required in this case.

For many patients, the signs of recovery, which appear after the first three weeks of the afflication, are adequate encouragement. But the real hard work for them comes when dealing with society. Toral refuses to take her veil off except when she is being medically examined. Believing that her children will "develop a horror" of her, she wears her veil even at home. At the same time she admits that her family has been very supportive.

Speaking of the reactions of people, Mains says: "There is a stratum of people who are normally intelligent but not so when it comes to someone who is visibly unwell. It becomes a mind game when dealing with people like them." As the superintendent of a large school, Mains chose to be open about his condition and found that he received a great deal of support from everyone.

The period of recuperation is not an easy one for the patient, who has to contend with the psychological aspect of disfigurement. Sorabjee says, "As doctors, we know that most patients will have total recovery but the patient is devastated because his facial symmetry is distorted."

Recalling his experience, Mains says: "The worst moment for me was the first time I met with the physiotherapist. I looked at myself in a mirror that was just six inches away from my face. That was the first time I really saw myself. It was very emotional."

Psychologically, facial paralysis can be devastating, particularly in cases that extend for a long period, or where residuals are significant. Bharucha says: "The patient's sense of self and self-esteem is deeply affected." Describing the period of his recovery, Mains says that even the smallest facial movement, like raising an eyebrow, was impossible in the first few weeks. "If there is one lesson I have learnt from this, it is never to take a smile for granted," he says.