Neuralgia
Pains which follow the paths of specific nerves.
Neuralgia is defined as an intense burning or stabbing pain caused by irritation of or
damage to a nerve. The pain is usually brief but may be severe. It often feels as if it is
shooting along the course of the affected nerve.
Causes & symptoms of Neuralgia
The causes of neuralgias are varied. Chemicals can cause nerve
irritation. Inflammation, trauma (including surgery), compression by adjacent structures
(tumors or inflamed tissues), and infections can all lead to neuralgias. In many cases,
however, the cause is unknown or unidentifiable.
Neuralgias are most common in elderly persons, but they can occur at any age.
Trigeminal neuralgia is the most common form of neuralgia. It affects the main sensory
nerve of the face, the trigeminal nerve ("trigeminal" literally means
"three origins", referring to the division of the nerve into three branches).
This condition involves sudden and short attacks of severe pain on one side of the face,
along one of the areas supplied by the trigeminal nerve. The pain attacks may be severe
enough to cause a facial grimace, which is classically referred to as a painful tic (tic
douloureux).
The cause of trigeminal neuralgia is occasionally a blood vessel or small tumor
pressing on the nerve. Disorders such as multiple sclerosis (an inflammatory disease
affecting the brain and spinal cord), certain forms of arthritis, and diabetes (high blood
sugar) can also cause trigeminal neuralgia, but most commonly a cause is not identified.
In this condition, certain movements such as chewing, talking, swallowing, or touching
an area of the face may trigger a spasm of excruciating pain.
A related but rather uncommon neuralgia affects the glosso-pharyngeal nerve, one of the
nerves that provide sensation to the throat. Symptoms of this neuralgia are short,
shock-like episodes of pain located in the throat.
Some other neuralgias occur after certain infections such as shingles, which is caused
by the varicella-zoster virus, a type of herpesvirus (postherpetic neuralgia). This can
produce a constant burning pain after shingles rash has healed. The pain is worsened by
movement or contact with the affected area.
Postherpetic neuralgia can be debilitating long after signs of the original herpes
infection have disappeared. Two other infectious diseases that can cause neuralgias are
syphilis and Lyme disease.
Diabetes is another common cause of neuralgias. This very common medical problem affects
almost one out of every 20 Americans during adulthood. Diabetes damages the tiny arteries
that supply circulation to the nerves, resulting in nerve fiber malfunction and sometimes
nerve loss.
Diabetes can produce almost any neuralgia, including trigeminal neuralgia, carpal
tunnel syndrome (a condition characterized by pain and numbness of the hand and wrist),
and meralgia paresthetica (problem manifested by numbness and pain in the thigh, due to
damage to the lateral femoral cutaneous nerve). Strict control of blood sugar may prevent
diabetic nerve damage and may accelerate recovery in patients who do develop neuralgia.
Other medical conditions that can be associated with neuralgias are chronic renal
insufficiency and porphyria (a hereditary disease in which the body can not get rid of
certain substances produced after the normal breakdown of blood in the body). Certain
drugs can also cause this problem.
Description of Neuralgia
Different types of neuralgia occur depending on the reason the nerve has been
irritated. Neuralgia can be triggered by a variety of causes, including tooth decay, eye
strain, or shingles (an infection caused by the herpes zoster virus). Pain is usually felt
in the part of the body that is supplied by the irritated nerve.
Symptoms of Neuralgia
- Pain located anywhere, usually superficial (on the surface of the body)
- Same location for subsequent episodes
- Sharp, stabbing pain or constant, burning pain
- Pain along the path of a specific nerve
- Impaired function of affected body part due to pain or muscle weakness due to
concomitant motor nerve damage.
- Increased sensitivity of the skin or numbness of the affected skin area (resembling the
effects of a local anesthetic such as a Novacaine shot)
Any touch or pressure is interpreted as pain. Movement may be painful.
Diagnosis
Neuralgia is a symptom of an underlying disorder; its diagnosis depends on finding the
cause of the condition creating the pain.
To diagnose occipital neuralgia, a doctor can inject a small amount of anesthetic into
the region of the occipital nerve. If the pain temporarily disappears, and there are no
other physical reasons for the pain, the doctor may recommend surgery to deal with the
pinched nerve.
Treatment
Glossopharyngeal, trigeminal, and postherpetic neuralgias sometimes respond to
anticonvulsant drugs, such as carbamazepine or phenytoin, or to painkillers, such as
acetaminophen. Trigeminal neuralgia may also be relieved by surgery in which the nerve is
cut or decompressed. In some cases, compression neuralgia (including occipital neuralgia)
can be relieved by surgery.
People with shingles should see a doctor within three days of developing the rash,
since aggressive treatment of the blisters that appear with the rash can ease the severity
of the infection and minimize the risk of developing postherpetic neuralgia. However, it
is not clear whether the treatment can prevent postherpetic neuralgia.
If postherpetic neuralgia develops, a variety of treatments can be tried, since their
effectiveness varies from person-to-person.
- Antidepressants such as amitriptyline (Elavil)
- Anticonvulsants (phenytoin, valproate, or carbamazepine)
- Capsaicin (Xostrix), the only medication approved by the FDA for treatment of
postherpetic neuralgia
- Topical painkillers
- Desensitization
- TENS (transcutaneous electrical nerve stimulation)
- Dorsal root zone (DREZ) surgery (a treatment of last resort).
Alternative treatment
B-complex vitamins, primarily given by intramuscular injection, can be an effective
treatment. A whole foods diet with adequate protein, carbohydrates, and fats that also
includes yeast, liver, wheat germ, and foods that are high in B vitamins may be helpful.
Acupuncture is a very effective treatment, especially for postherpetic neuralgia.
Homeopathic treatment can also be very effective when the correct remedy is used. Some
botanical medicines may also be useful. For example, black cohosh (Cimicifuga racemosa)
appears to have anti-inflammatory properties based on recent research.
Prognosis
The effectiveness of the treatment depends on the cause of the neuralgia, but many
cases respond to pain relief.
Trigeminal neuralgia tends to come and go, but successive attacks may be disabling.
Although neuralgia is not fatal, the patient's fear of being in pain can seriously
interfere with daily life.
Some people with postherpetic neuralgia respond completely to treatment. Most people,
however, experience some pain after treatment, and a few receive no relief at all. Some
people live with this type of neuralgia for the rest of their lives, but for most, the
condition gradually fades away within five years. |
