The nerves play an important role in the body by carrying signals to and from the spinal cord and brain (central nervous system). In this way sensory signals can feed back sensations to the central nervous system (CNS) and transmit signals to different parts of the body from the CNS. It is one of the body’s way of getting information about the environment (both internal and external) as well as exerting an influence on the different organs and structures. Sometimes the nerves can be diseased or damaged thereby triggering sensations even without any underlying problem.
What is neuralgia?
Neuralgia is the term for nerve pain. It must be differentiated from other types of pain because the problem lies in the nerve itself. Normally we feel pain at a certain part of the body when it is injured. Pain warns us that tissue damage is occurring and we must try to act to remove the cause of the injury. It essentially tells us that all is not well in the body. The signals generated from the pain receptors where the damage is occurring is fed back to the CNS through the nerves and perceived as the sensation of pain.
However, when the nerve itself is undergoing some injury or is malfunctioning in some way, pain signals may be generated despite there sometimes being no tissue damage of the surrounding area. We refer to this as nerve pain, or neuralgia. There are many different types of neuralgia classified according the area, nerve involved or cause of the neuralgia. It can be a difficult condition to treat when there is no clear underlying cause that can be targeted. At times a neuralgia can become a chronic disorder leading to months, years or even a lifetime of pain.
Types of Neuralgia
There are a wide variety of neuralgias. As mentioned, it is classified according to:
- The area where the neuralgia emanates.
- The nerve affected in the neuralgia.
- The cause of the nerve irritation or damage.
The three most common types of neuralgias are:
- Post-herpetic neuralgia, also known as shingles, arises with reactivation of the chickenpox virus. It can then damage the nerve fibers and lead to long periods of pain as well as skin symptoms along the affected areas.
- Trigeminal neuralgia is nerve pain involving the trigeminal nerve. It is usually a chronic condition involving the trigeminal nerve which relays sensory signals from the face to the brain. Pressure on the nerve is most frequently the underlying cause.
- Sciatica or sciatic nerve pain is another type of neuralgia. It occurs when there is pressure on the root of the sciatic nerve at the lower back. As a result there is pain along the distribution of the sciatic nerve usually extending from the back down the leg.
Some of the other types of neuralgia include:
- Glossopharyngeal neuralgia involving the glossopharyngeal nerve with pain at the back of the tongue, throat and near the ear.
- Intercostal neuralgia involving the intercostal nerves between the ribs leading to chest wall pain.
- Occipital neuralgia involving the the occipital nerves in the neck and leads to pain in the neck, upper back and scalp.
Causes of Neuralgia
These are some of the more likely causes of neuralgia. However, there are times where the cause of a neuralgia is unknown and it is termed as idiopathic.
- Trauma – injury to the nerve with blunt or sharp force trauma, including nerve injury due to surgery.
- Pressure – compression of the nerve by surrounding structures in the body.
- Infections – certain viruses and bacteria in particular can infect nerves, like shingles, syphilis HIV, Lyme disease.
- Chemicals – endogenous (produced within the body) and exogenous (sourced from outside) can irritate nerves.
- Chronic diseases – chronic kidney disease, diabetes mellitus, porphyria.
- Medication – a number of drugs may cause neuralgia as a side effect, especially chemotherapeutic (anti-cancer) drugs.
Read more about types and causes under peripheral neuropathy.
Signs and Symptoms
Neuralgia is a symptom and not a disease on its own. The pain varies in nature but is usually described as a burning, shooting or stabbing pain. Pressure on the area like during firm touch may further exacerbate the pain. Sometimes there is only tenderness (pain with pressure). Typically the pain is localized to a specific area although it may extend along the course of the affected nerve. Despite the predominant feature being pain, there may also be numbness in that other sensations are not felt. The pain can be intermittent or constant.
Although neuralgia does not usually affect the functioning of an area, there may be some degree of muscle weakness or spasm in the affected area. In rare instances there can be complete paralysis if corresponding motor nerves (nerves that control muscles) are also affected or if the affected nerve has a combination of sensory and motor fibers (mixed nerves). Paresthesias like tingling, prickling or formication (crawling insect sensation) may precede the onset of pain is some types of neuralgias.
Treatment of Neuralgia
The treatment for neuralgia largely depends on the underlying cause. It may require the use of medication and/or surgery. Ideally the treatment should be directed at the cause of the neuralgia, like medication to treat an infection or surgery to relieve the pressure off the nerve. However, the neuralgia can persist even after the cause is treated. Furthermore the cause cannot be treated in idiopathic cases since the cause is unknown. In these instances the treatment is directed at the nerve pain itself.
- Over-the-counter and prescription painkillers.
- Anesthetic patches or injections.
These drugs offer symptomatic relief to manage pain until the underlying cause can be treated or resolves on its own. However, neuralgias can become a chronic condition meaning that medication may be necessary to some degree or the other for a long periods of time. Physical therapy may also be helpful in managing the pain. Occupational therapy and psychotherapy may be advisable in order to cope with the pain and continue with daily tasks.
- Nerve blocks may involve anesthetic injections or temporary disrupting nerve fibers to reduce pain signals.
- Neurectomy where the nerve is cut or removed to permanently stop pain signals.
- Other procedures depending on the cause, like to reduce pressure in nerve root compression.