Neuralgia

Injury	Disease	Nutrition	Poison

Symptoms	Surgery	Test	Special Topic

Central nervous system

Neuralgia

Alternative Names:

Nerve pain; Postherpetic neuralgia
Symptoms:

Pain located anywhere, usually on or near the surface of the body
- In the same location for each episode
- 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 (feeling similar to a local anesthetic such as a Novacaine shot)

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Any touch or pressure is interpreted as pain. Movement may also be painful.

Signs and tests:

Neurologic examination shows tenderness occurring along a nerve tract. Trigeminal neuralgia usually causes pain along the second and third nerve divisions (lower face and jaw), and rarely involves the first nerve division (temple and forehead). Other signs of altered nerve function may be often encountered, such as loss of deep tendon reflexes, local loss of muscle bulk, local lack of sweating (sweating is regulated by nerve function), and abnormal skin sensation.

There may be specific trigger points (areas where even a slight touch triggers pain). A dental examination is used to rule out dental disorders that may cause facial pain. The presence of other symptoms (such as redness or swelling) may indicate disorders causing the pain, such as infections, bone fractures, rheumatoid arthritis, or other disorders.

No tests are specific for neuralgia, but tests may be used to rule out other causes of the pain. Sometimes a nerve conduction study with electromyography (NCS/EMG), which examines the electrical activity of nerves, may confirm the diagnosis.

The first part of the test, the NCS, involves giving small electric shocks to skin areas overlaying specific nerve paths. The physician then determines whether the conduction of electricity is delayed or blocked through the particular nerve that was tested.

The second part of the test, the EMG, involves the careful insertion of a very fine needle into the skin, which is attached to an electric probe. The measure of electrical activity of the sampled muscle at rest and during motion indirectly provides useful clues regarding nerve function. Although the procedure sounds rather unpleasant, most patients are able to tolerate it with little discomfort.

There are a number of other laboratory tests doctors use to determine the cause of neuralgia. Blood tests to check blood sugar and kidney function are routinely used. When the diagnosis is not clear, other tests may be helpful -- particularly whenever there is suspicion of an underlying medical problem like arthritis, syphilis, vitamin deficiencies, or other less common disorders. If multiple sclerosis is suspected, the diagnosis usually can be confirmed with an imaging test of the brain such as MRI.

A lumbar puncture (spinal tap) is often used to confirm the diagnosis of multiple sclerosis and other nerve disorders. It involves inserting a needle into the lower back to reach a spot called the subarachnoid space, which is filled with cerebrospinal fluid (CSF). Analysis of this fluid may show evidence of inflammation, helping to establish the correct diagnosis.