The facial nerve controls the muscles of expression and emotion in the face and caries taste sensations from the front of the tongue to the brain. In facial palsy, one of the two facial nerves is damaged, compressed, or inflamed, and this results in weakness of the facial muscles, causing the eyelid and corner of the mouth to droop on one side of the face. People with facial palsy are often concerned that they have had a stroke, but this is unlikely if only the face is affected because a stroke is usually also associated with muscle weakness in other parts of the body.

Facial palsy is usually temporary, but a full recovery may take several months. The disorder affects about 1 in 4,000 people in the UK each year.

What are the causes?

The most common form of facial palsy is Bell’s palsy. This type of palsy occurs for no known reason, although a viral infection is believed to play a part.

In order types of facial palsy, there are known causes of damage to the facial nerve. These include the viral infection shingles and the bacterial infection Lyme disease. In addition, the facial nerve sometimes becomes inflamed as a result of middle-ear infection. In rare cases, the facial nerve may be compressed by a tumour called an acoustic neuroma. Facial palsy can also result from damage to the nerve from a tumour of the paroid salivary gland.

What are the symptoms?

In some cases, such as in Bell’s palsy, the symptoms of facial palsy appear suddenly over about 24 hours. In other cases, including facial palsy caused by an acoustic neuroma, symptoms may develop slowly. The symptoms include:

- Partial or complete paralysis of the muscles on one side of the face.
- Pain behind the ear on the affected side of the face.
- Drooping of the corner of the mouth, sometimes associated with drooling.
- Inability to close the eyelid on the affected side and watering of the eye.
- Impairment of taste.

If facial palsy is very severe, you may have difficulty in speaking and eating, and, occasionally, sounds may seem unnaturally loud in the ear on the affected side. If the eyelid cannot be closed, the eye may become infected, leading to ulceration of the cornea, the transparent front part of the eye. In facial palsy due to shingles, you will also have a rash of crusting blisters on your ear.

How is it diagnosed?

Your doctor will probably be able to diagnose facial palsy from your symptoms alone. A rapid onset over about 24 hours suggests Bell’s palsy. Symptoms that develop more slowly usually indicate another cause.

If your doctor suspects a tumour may be compressing the facial nerve, he or she may arrange for you to have CT scanning or MRI. Nerve and muscle electrical tests may also be arranged to assess nerve damage. If you live in a part of the UK where Lyme disease is common, you may have a blood test to look for evidence of this disorder.

What might be done?

If your symptoms have appeared in the last 48 hours, your doctor may prescribe corticosteroids for up to 2 weeks to reduce inflammation of the nerve. He or she may also recommend that you take painkillers. To prevent damage to the cornea, you may be given artificial tears, and you will probably be advised to tape the affected eye shut when you go to sleep.

Bell’s palsy usually clears up without further treatment. If facial palsy has an underlying cause, it will be treated if possible. For example, if facial palsy is due to shingles, antiviral drugs, such as aciclovir, will be prescribed. To be effective, treatment with acyclovir should begin as soon as the rash appears. If you have an acoustic neuroma, it will be removed surgically to relieve compression of the facial nerve.

If muscle paralysis persists, plastic surgery may be used to reroute another nerve to the face. Facial exercises and massage may help to maintain tone.

What is the prognosis?

With appropriate treatment, facial palsy usually improves within about 2 weeks. However, a full recovery may take up to 3 months. Some people are left with weakness, and facial palsy may recur.

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The carpal tunnel is the narrow space formed by the bones of the wrist (carpal bones) and the strong ligament that lies over them. In carpal tunnel syndrome, the median nerve, which controls some hand muscles and conveys sensation from nerve endings in part of the hand, is compressed where it passes through the tunnel. This compression causes painful tingling in the hand, wrist, and forearm. Carpal tunnel syndrome is a common disorder, especially in women aged 40-60, and often affects both hands.

What are the causes?

In some cases, the underlying cause of nerve compression is not known. In others, it occurs because the soft tissue within the carpal tunnel swell, compressing the median nerve at the wrist. Such swelling may be due to diabetes mellitus, or it may occur during pregnancy. The carpal tunnel may also be narrowed by a joint disorder, such as rheumatoid arthritis, or by a wrist fracture. The syndrome is associated with work that involves repetitive hand movements, such as typing, which can result in inflammation of the tendons in the wrist.

What are the symptoms?

Symptoms mainly affect specific areas of the hand, such as thumb, the first and middle fingers, and the palm of the hand. Initially, symptoms may include:

- Burning and tingling in the hand.
- Pain in the wrist and up the forearm.

As the condition worsens, other symptoms may gradually appear including:

- Numbness of the hand.
- Weakened grip.
- Wasting of some hand muscles, particularly at the base of the thumb.

Symptoms may be more severe at night, and pain may interrupt sleep. Shaking the affected arm may temporarily relieve symptoms, but the numbness may become persistent if left untreated.

What might be done?

Your doctor may suspect carpal tunnel syndrome from your symptoms. He or she will examine your wrists and hands may tap the inside of your wrists to check if a tingling sensation occurs. Nerve conduction studies may be carried out to confirm the diagnosis. If pregnancy is the cause of carpal tunnel syndrome, the symptoms usually disappear after childbirth. In other cases, treating the cause, if it can be identified, usually relieves symptoms.

The symptoms of carpal tunnel syndrome may be relieved temporarily by nonsteroidal anti-inflammaroty drugs or by wearing a wrist splint, particularly at night. In some cases, a corticosteroid injection under or around the ligament may reduce swelling. If symptoms persist or recur, you may have surgery under local anaesthesia to cut the ligament and release pressure on the nerve. After surgery, there are usually no further symptoms.

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Sciatica is a form of nerve pain that may be felt anywhere along the course of one of the sciatic nerves, the two largest nerves in the body and the main nerve in each leg. The sciatic nerves are formed from nerve roots in the lower part of the spinal cord. They run from the base of the spine down the backs of the thighs to above the knees, where they divide into branches that supply the front and back of the leg and foot. The pain of sciatica is caused by compression of or damage to the sciatic nerve, usually where it leaves the spinal cord. Many people have at least one episode of sciatica during their lives. Often, only one leg is affected. In most cases, the pain disappears gradually over about 1-2 weeks, but it may recur.

What are the causes?

Sometimes, the cause of sciatica is unknown. However, in people aged 20 to 40, the most common cause is a prolapsed or herniated disc in the spinal column that presses on a spinal nerve root. Sciatica may also develop from spondylolisthesis, in which a vertebra (bone in the spine) slips out of position. In older people, sciatica may be caused by changes in the spine as a result of various conditions, such as osteoarthritis. Women may develop sciatica during the last months of pregnancy because of posture changes that cause increased pressure on the sciatic nerve.

Muscle spasm and sitting in an awkward position for long periods of time are relatively common causes of brief episodes of sciatica in all age groups.

Less commonly, sciatica may be the result of an injection into the buttock muscles that was mistakenly given too close to one of the sciatic nerves. Rarely, a tumour on the spinal cord may press on the sciatic nerve roots.

What are the symptoms?

The symptoms can be mild or severe, with spasmodic or persistent pain in the affected leg. Symptoms may include:

- Pain that is made worse by movement or by coughing.
- Tingling or numbness.
- Muscle weakness.

If sciatica is severe, you may have difficulty in lifting the foot on the affected side because of muscle weakness, and you may be unable to stand upright. Some people have difficulty in walking.

What might be done?

The doctor will examine you and test your leg reflexes, muscle strength, and sensation. You may be advised to rest in bed on a firm mattress for a couple of days and be given painkillers to relieve discomfort. If symptoms persist, you may have tests, such as MRI of the spine, to look for changes in the bones or a prolapsed disc.

Sciatica as a result of pregnancy will usually disappear after childbirth. Pain caused by muscle spasm or sitting awkwardly also tends to clear up without treatment. Occasionally, the condition can be helped by regular physiotherapy, exercise, or chiropractic treatments. However, sciatica can recur. In some cases, surgery may be necessary to relieve pressure on the nerve.

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The trigeminal nerve transmits sensation from parts of the face to the brain and controls some of the muscles that are involved in chewing. Damage to this nerve causes repeated bursts of sharp, stabbing pain, known as trigeminal neuralgia, in the lip, gum, or cheek on one side of the face. Attacks may last for a few seconds or several minutes and may become more frequent over time. In severe cases, the pain may be so intense that the affected person is unable to do anything during the attack. Afterwards, the pain usually disappears completely. An attack may occur spontaneously or be triggered by certain facial movements, such as chewing, or by touching a trigger spot on the face. Attacks rarely occur at night.

Trigeminal neuralgia affects about 1 in 25,000 people in the UK. The disorder is most common in men over the age of 50. The cause of trigeminal neuralgia is usually unknown. However, in people under 50, symptoms may be an early sign of multiple sclerosis. Rarely, the nerve is compressed by a tumour or by a dilated blood vessel.

What may be done?

There are no specific tests to diagnose trigeminal neuralgia. Your doctor will examine you to rule out any other causes of facial pain, such as toothache or sinusitis. He or she may also arrange for you to have MRI to look for the presence of a tumour.

Your doctor may prescribe painkillers, such as paracetamol or ibuprofen. However, if the pain persists, your doctor may prescribe anticonvulsant drugs, such as carbamazapine, or certain antidepressants, all of which have been shown to be effective in treating trigeminal neuralgia. Unlike painkillers, which are taken only when the pain is present, both anticonvulsants and antidepressants need to be taken every day to prevent attacks.

If a tumour is found, surgery may be necessary to remove it. Surgery may also be used to separate the trigeminal nerve from a blood vessel if the vessel is compressing the nerve. Rarely, people who have persistent, severe pain that does not respond to drugs are offered treatment to numb the affected side of the face. For example, pain can be alleviated by using a heated probe to destroy the nerve. Alternatively, the trigeminal nerve may be cut, or alcohol may be injected into the nerve to deaden it. Trigeminal neuralgia will not recur after treatment to numb the face, but you will need to take care when consuming hot food or drinks because of the lack of sensation in your face.

Attacks of neuralgia may stop spontaneously, become more frequent, or persist unchanged for months or years. However, symptoms usually improve significantly with treatment.

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In nutritional neuropathies, the peripheral nerves, which branch from the brain and spinal cord, are damaged by deficiencies of essential nutrients, particularly those of the vitamin B complex.

Worldwide, nutritional neuropathies are generally caused by malnutrition. In developed countries, such neuropathies are more commonly associated with excessive alcohol consumption. People who drink heavily often also have a poor diet, which can cause a vitamin B deficiency. In addition, alcohol may directly damage the peripheral nerves. A person who has been drinking heavily for 10 years or more has a greatly increased risk of developing a nutritional neuropathy.

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Nutritional deficiencies may occur in people with eating disorders, such as anorexia nervosa. People with long-term conditions that affect absorption of nutrients from the intestines may also develop nutritional deficiencies.

What are the symptoms?

Nutritional neuropathies usually first affect the tips of the fingers and the toes. The symptoms appear gradually over several months or years and slowly progress up the limbs to the trunk. Symptoms may include:

- Loss of sensation.
- Pins and needles.
- Pain in the feet and/or the hands.

Walking may be clumsy as a result of the loss of sensation in the feet and legs.

If the motor nerves (nerves that stimulate the muscles) are affected, muscle weakness and wasting may develop and further affect the ability to walk.

What might be done?

Your doctor will examine you by checking your reflexes and your ability to feel sensation such as a pin prick. He or she may arrange for blood tests to look for a vitamin deficiency or for evidence of liver damage caused by excessive alcohol consumption. Your doctor may also arrange for tests that measure the extent of the nerve damage.

Nutritional neuropathies are treated by replacing the missing nutrients. This is done either by giving a course of oral supplements or, in some cases, by injections. Your doctor may also prescribe anticonvulsant drugs or antidepressants to help to control the symptoms. You may also be prescribed painkillers to relieve any discomfort. Nerve damage is usually irreversible, but with treatment the progression of the disease can usually be halted.

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In diabetic neuropathy, one or more of the peripheral nerves that branch from the brain and spinal cord to the rest of the body are damaged as a result of diabetes mellitus. Diabetic neuropathy is the most common cause of peripheral neuropathy in developed countries. If diabetes is poorly controlled, it results in high levels of glucose in the blood that damage the peripheral nerves directly and the blood vessels that supply them. Good control of diabetes reduces this risk by up to half.

About 3 in 10 people with diabetes mellitus have damage to one or more peripheral nerves, but only 1 of these 3 people develops significant symptoms.

People with diabetes mellitus who smoke increase the risk of damaging the blood vessels that supply the nerves,

What are the symptoms?

The symptoms of diabetic neuropathy usually develop slowly over a number of years. Rarely, they develop rapidly over days or weeks. Symptoms vary depending on which nerves are involved, but the feet are frequently affected. Less commonly, diabetic neuropathy may affect the larger nerves, mainly in the thighs. Symptoms may include:

- Pins and needles.
- Numbness.
- Pain, which is often worse at night.
- Muscle weakness and wasting.

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In sensation is lost, a minor injury to the foot, such as rubbing by badly fitting shoes, may not be noticed. Slow healing due to poor blood supply may lead to infection. If left untreated, ulcers may develop and, in severe cases, gangrene occurs.

Eventually, diabetic neuropathy may also affect the autonomic nerves that regulate automatic body functions such as blood pressure control and digestion. Damage to these nerves causes symptoms such as dizziness when standing, diarrhea, and impotence.

What might be done?

Careful control of diabetes reduces the risk of developing diabetic neuropathy. However, if you develop symptoms of nerve damage, you should consult your doctor. He or she will probably be able to diagnose the condition from your symptoms. However, nerve conduction tests may need to be carried out in hospital to confirm which nerves are affected and to assess the severity of the damage. The goal of treatment of diabetic neuropathy is to prevent further nerve damage and the development of complications. Your doctor will help you to monitor your blood sugar level carefully and advise you about good foot care. For example, you should check your feet regular for cuts or abrasions, particularly if you have been wearing new shoes. You should avoid wearing open-toed sandals or walking barefoot. If you smoke, you should try to give up.

To relive pain, particularly at night, certain anticonvulsant drugs, such as carbamazepine and phenytoin, or an antidepressant drug, such as amitriptyline, may be prescribed.

What is the prognosis?

Good control of blood glucose levels in diabetes mellitus not only reduces the risk of developing diabetic neuropathy but may also half further progression of the disease. However, in most cases, nerve damage is irreversible.

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Disorders of the peripheral nerves, the nerves that branch from the brain and spinal cord to the rest of the body, are called neuropathies. Depending on the nerves affected, peripheral neuropathies may affect sensation, movement, or automatic functions, such as bladder control. Rarely, a peripheral neuropathy may be life-threatening.

What are the causes?

In developed countries, the most common cause of damage to the peripheral nerves is diabetes mellitus. Vitamin B complex deficiencies and some nutritional disorders may also result in nerve damage. In the developed world, nutritional neuropathy is often the result of a poor diet in people who abuse alcohol. Drinking too much alcohol may also damage peripheral nerves directly.

Damage to a single nerve may occur as a result of an injury or because of compression. For example, in carpal tunnel syndrome, the median nerve, which supplies that part of the hand, is compressed at the wrist.

Neuropathy may also be associated with an infection, such as Hansen’s disease or HIV infection. Guilain-Barre syndrome, a neuropathy that is rapidly progressive, is caused by an abnormal immune response that sometimes occurs after an infection.

Autoimmune disorders such as systemic lupus erythematosus, in which the immune system attacks the body’s tissues, may cause nerve damage occasionally, a disorder such as polyarteritis nodosamay damage nerves by causing inflammation of the blood vessels that supply them. Neuropathy may also result from certain cancers, particularly primary lung cancer and lymphoma. Occasionally, neuropathy is caused by amyloidosis, in which an abnormal protein is deposited in the body.

Some drugs, such as isoniazid, may cause nerve damage, as may exposure to certain toxic substances, such as lead. In some cases, the cause is unknown.

A painless ulcer developing under the big toe joint due to peripheral neuropathy

What are the types?

Peripheral neuropathies may affect the nerves that transmit sensory information (sensory nerves), the nerves that stimulate the muscles (motornerves), and/or the nerves that control automatic functions (autonomic nerves).

Sensory nerve neuropathies: these neuropathies first affect the hands and feet and the spread towards the centre of the body. The symptoms may include tingling, pain, and numbness in the affected area. If the fingertips are numb, everyday tasks may become difficult. This type of neuropathy is most often caused by nutritional disorders or drugs.

Motor nerve neuropathies: if the motor nerves are damaged, the muscles they supply become weak, and wasting occurs eventually. In severe cases, mobility may become restricted, and very rarely, breathing may have to be assisted by mechanical ventilation. Lead poisoning may result in a neuropathy that affects the motor nerves only.

Autonomic nerve neuropathies: a neuropathy that is affecting one or more autonomic nerves may result in constipation, fainting due to low blood pressure, diarrhoea, urinary in continence, or impotence. This type of neuropathy is often caused by long-standing diabetes mellitus.

What might be done?

Your doctor may be able to tell which nerves are affected from your symptoms and an examination. If the cause of your neuropathy is not clear, he or she will probably arrange for blood tests to look for evidence of an underlying disorder, such as nutritional deficiencies or an autoimmune disorder. If Mere is evidence of compression of a nerve, you may also have CT scanning or MRI to assess the severity and extent of nerve damage. Special tests to assess the function of the nerves may also be carried out.

The treatment of a peripheral neuropathy depends on the cause and the type of nerve affected. For example, careful control of diabetes mellitus may keep diabetic neuropathy from worsening, and vitamin B complex injections may help a nutritional neuropathy. If motor nerves are affected, you may have physiotherapy to help to maintain muscle tone. Wearing a foot splint may assist walking. Sometimes, the underlying cause can be treated, but long-standing nerve damage may be irreversible.


TEST NERVE AND MUSLCE ELECTRICAL TESTS

Nerve and muscle electrical test consist of nerve conduction studies and electromyography (EMG). Nerve conduction studies are used to assess how well a nerve is conducting electrical impulses. They are often followed by EMG to see whether symptoms, such as weakness, are due to a disorder of the muscle or the nerve supplying it. Both tests are usually done on an outpatient basis. Each takes about 15 minutes and may cause discomfort.

Nerve conduction studies

Nerve conduction studies are carried out to assess nerve damage in disorders such as peripheral neuropathies. A nerve is stimulated by an electrical impulse, and the response to the stimulus and the speed at which this response travels along the nerve indicates whether the nerve is damaged and the nature and extent of the damage.

Electromyography

EMG is used to differentiate between nerve and muscle disorders and to diagnose disorders such as muscular dystrophy. A fine needle is used to record the electrical activity of a muscle at rest and when contracting. The results are recorded on a trace.

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