Definition and causes of Nerve Pain - Neuralgia

Neuralgia is pain that occurs because of a disturbance in one of the nerves transmitting sensory input to the brain.

The pain occurs in the nerve innervation area, which means the part of the body from where the nerve signal originates. There are many different types of nerve pain depending on which nerve is damaged/disrupted, and the operative cause of the condition.

Nerve pain typically stems from a damaged nerve. Injury or illness in a nerve is called neuropathy. This is visible for example in diabetes patients or in connection with nerve damage as a result of trauma such as surgery or injury and also from damage to the spinal cord or blood clots in the nervous system. Phantom pain is also a form of nerve pain.

In addition, there are 3 particular types of nerve pain:

• Trigeminal neuralgia: (Also called Tic douloureux)
  The pain stems from disruption of the function of the trigeminal nerve, which is the facial sensory nerve. The condition is more common in women than in men and strike mostly people over 50 years of age. The trigeminal nerve has three prongs. The ophthalmicus nerve transmits sensory impulses from the skin of the top of the scalp down over the forehead and onto the nose. The second prong n. maxillaris leads sensory impulses from the very outer part of the forehead down across the cheek, the nosetip and upper lip. The third prong n. mandibularis leads sensory impulses from the temple downwards to the lower jaw and lower lip.
  
  The symptom of Trigeminal neuralgia is facial pain arriving as sudden attacks. Typically, these attacks last up to 2 minutes. It is typically series of short-term shooting pain involving the sensory innervation area of one, or rarer, two prongs. It is usually the second or third prong, which is affected, unless Trigeminal neuralgia is associated with multiple sclerosis, where the first prong might be affected.
  
  The cause of Trigeminal neuralgia is normally not known. The pain occurs most frequently during the day and can be triggered by talking, chewing, cough, tooth brushing, food or fluid intake. Some patients have a skin or mucous membrane area, which by slight stimulation triggers pain. This is called a Trigger zone. Some patients have tears in connection with attacks.

• Glossopharyngeusneuralgi:
  This is a rare and painful condition in the glossopharyngeus nerve innervation area. The pain occurs in the area around the tonsils and the ear. There may be a trigger zone at the rear of the tongue, in the throat, tonsils or at the ear. The condition can be triggered by cancer of the pharynx or after radiotherapy to the jaw or neck.

• Post herpes nerve pain:
  After an outbreak of shingles (herpes zoster) there can still be pain in the area of the skin which was attacked by the virus, although the skin has completely healed up. The pain can last for many years after the incidence. The risk of getting post-neuralgia is greater, the older you are. In people with shingles who are under 40 years, the risk is less than 10%, while for those over 70 years is about 75%. The pain is burning, searing or clenching of nature and there may be shooting pain. The sensory sensation will often change with the skin being more sensitive resulting in pain from impact which would normally not be painful. 

Symptoms of nerve pain

The main characteristics of nerve pain are: 

• Attacks of stabbing, shooting, burning, tingling or searing pain, typically affecting the skin. 

• No visible tissue damage. 

• Symptoms typically occur a bit after the actual damage occured. 

• The pain can be found in areas with decreased tactile sense. 

• The pain is caused by stimuli that would normally not cause pain. 

• The pain is exacerbated by recurrent pain stimulation. 

• Pain continues after pain stimulation has been stopped. 

Precautions and diagnosis

If you are experiencing nerve pain, you should consult you general practitioner for examination. Usually, the description of the symptoms and a normal neurological examination is enough to make the diagnosis. If there is suspicion of underlying disease additional examination will take place investigation. For example, multiple sclerosis will often be suspected if trigeminal neuralgia occurs in a person less than 40 years of age.

Treatment of Neuralgia or Neuropathic pain

Nerve pain is not relieved very well with ordinary pain killer medication as the pain mechanism is different than normal pain. Applied treatment is the following: 

• Medicines that are normally used for epilepsy, for example oxcarbazepin or carbamazepine. The dose of the medication is increased gradually. Approximately 75% of patients respond positively to this treatment. In addition, drugs commonly used to treat depression, known tricyclicantidepressants might be prescribed with good effect. Often, the two types of drugs are used in combination.

• Attacks of trigeminal neuralgia can be blocked by giving lidocaine or phenytoin directly into a vein. Another treatment is injection of glycerol into the area where the nerve originates or treatment of this area with heat.

• Operation may sometimes be necessary in trigeminal neuralgia if the reason for the condition is the trigeminal nerve being squeezed somewhere in its path. The objective of the surgery is to make better room for the nerve and thus relieve the condition.

• Transcutaneous nerve stimulation (TNS or TENS) which sends electric currents through the skin in the area where there is nerve pain. The patient may even have a machine at home, which can then be used when pain occurs.

• Tight clothing in areas where there is pain seems soothing to some patients. 

Outlook and complications

Usually nerve pain decreases slightly with time. However, there will almost always be residual problems. Some people may be so severely affected by the nerve pain that the condition becomes all absorbing with the risk of leading to depression. 

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