What is neuropathic pain?
Neuropathic pain is a type of pain that, unlike ordinary pain, does not arise as a result of a reaction to physical damage, but as a result of the pathological excitation of neurons in the peripheral or central nervous system, which are responsible for the response to physical damage to the body (ordinary pain).
Neuropathic pain may be associated with abnormal sensations (dysesthesia) or pain caused by stimuli that normally do not cause pain (allodynia). It may be permanent and / or episodic. The latter can be piercing or similar to electric shocks. Common qualities include burning or cold, goose bumps and needles, numbness and itching. The cause of neuropathic pain can be pathological processes in the peripheral and central nervous system. Thus, peripheral neuropathy, neuropathic pain of central and mixed genesis is distinguished. Neuropathic pain affects 7–8% of the European population, and in 5% of people it can be severe.
Neuropathic pains, as a rule, have a chronic course.
For the subjective characterization of NB, patients use definitions such as stinging, piercing, shooting, cutting. These pains are characterized by a complex of specific sensory disorders, which can be divided into two groups. On the one hand, these are positive spontaneous (spontaneous pain, dysesthesia, paresthesia) and caused (allodynia, hyperalgesia, hyperesthesia, hyperpathy) symptoms, on the other - negative (hypesthesia, hypalgesia) symptoms of loss of function of damaged structures. NB is characterized by a combination of positive and negative symptoms, varying in the same patient during the course of the disease.
Very characteristic of the neuropathic type of pain is the phenomenon of allodynia - the appearance of pain in response to a stimulus that does not cause it in healthy people. In such cases, patients experience severe pain at the slightest touch, sometimes even when the wind blows.
There are temperature and mechanical allodynia. Mechanical is divided into static, which appears when pressure is applied to a fixed point of the skin, and dynamic that occurs when moving stimuli (irritation of the skin with a brush or finger).
During hyperalgesia, the sensitivity to the pain stimulus is significantly higher than expected in normal conditions. In hyperpathy, the subjective response to both painful and non-painful stimuli is excessive and often persists for a long time after the cessation of irritation. Feelings of tickling, painless tingling, and other similar sensations belong to paresthesias; if these sensations hurt, they are called dysesthesies. A typical example of NB is the phenomenon of neuralgia (trigeminal, postherpetic). One of the characteristic symptoms of NB is causalgia - intense persistent burning pain, often of a lancinating nature, combined with allodynia and hyperpathy and often accompanied by vascular and trophic disorders. The combination of burning pain with pronounced trophic disorders, as well as the effectiveness in some cases of sympathetic blockades served as a pretext for the participation of the sympathetic nervous system in the formation of this pain. This pain is also called sympathetic pain.
The clinical signs of NB are
- no reason for direct irritation of nociceptors in the periphery (trauma, inflammation, ischemia);
- persistent, prolonged pain;
- the ineffectiveness of analgesics for the relief of pain;
- localization of pain in the area of sensory defect, corresponding to the defeat of any part of the nervous system;
- the presence of stimulating pain-related phenomena - allodynia, hyperalgesia, hyperesthesia, hyperpathy;
- combination with autonomic disorders in the field of pain in the form of reduced blood flow, hyper or hypohydrosis, etc .;
- combination with motor disorders;
- frequent deterioration of well-being at night.
Patients' complaints with pathognomonic pain descriptors include the following definitions: burning, shooting, jerking, cutting, or comparable to the sensation of passing an electric current.
NB is characterized by comorbid disorders, in particular, sleep disturbances, mood disorders in the form of symptoms of depression and anxiety. The prevalence of depressive and anxiety disorders in patients with NB is significantly higher than in the general population. In patients with a combination of chronic pain and depression, the quality of life is worse and the intensity of pain is higher. Anxiety is also a frequent comorbid state in NB. Patients with chronic pain usually experience anxiety as a result of the stress of living with pain. Pain can cause changes in anxiety, and increased anxiety can increase the perception of pain.
Neuropathic pain of central genesis is observed in spinal cord injuries, multiple sclerosis, and sometimes in strokes. In addition to diabetes, the most common causes of pain in peripheral neuropathy are herpes infection, HIV-associated neuropathy, lack of certain nutrients, the action of toxins, paraneoplastic syndrome, disorders of the immune system, trauma to the nerve trunks. Peripheral polyneuropathy is the most common symptom in Fabry disease.
Neuropathic pain is often found in cancer; it is caused by the direct effect of a tumor on peripheral nerves (for example, by compression) or as a side effect of chemotherapy, radiation therapy or surgery.
Characteristic sensations in neuropathic pain
- Passing electric current
- Shooting pains
These pains are common
We are all familiar with the pain - whether it is a headache, toothache or muscle pain after exercise. But there is a completely different pain that is associated with damage to the nerves. That it often becomes painful, violates human life for many months or years. This pain is called neuropathic.
.. It seemed to me stupid to go to the doctor for numbness in the feet. I would like to know earlier that this is a neuropathic pain and it can be treated ..
It occurs in 6-7 out of 100 people. Neuropathic pain can make performing even the most basic actions, such as putting on socks, a shirt, walking, impossible. Often people do not understand what this pain is and how to tell the doctor about it. They cannot find words to describe it. Therefore, these patients often do not receive adequate care and necessary treatment.
How does neuropathic pain arise
In our body there are millions of nerves that interact with each other. Together they form the nervous system. Imagine a lot of electrical and telephone wires connecting your brain to different parts of the body. For example, when you step on the beach on the hot sand, the nerves located on the foot send a signal to the brain, indicating that you are stepping on something hot. As a result, you feel a burning sensation in your foot. Or, if you accidentally touched a bare electrical wire, the nerves on your hand send a quick signal to the brain that you were electrocuted.
But if nerve damage occurs, they start to work incorrectly and send the wrong signals to the brain. For example, damaged nerves can tell the brain that you have stepped on a hot one or touched an electrical wire. And this is despite the fact that you really did not step on anything and did not touch anything. Nerves can be damaged as a result of many causes, such as diabetes, herpes infection, injuries to hands and feet, abnormalities in the spine, strokes, oncological diseases, etc.
Neuropathic pain is like ...
Many people with neuropathic pain often do not describe their feelings as pain. On the contrary, they can talk about how they feel "a lot of needles, splinters", "goosebumps", tingling, numbness, they feel "the passage of electric current."
... I felt like I was walking on broken glass ...
... as if a hot needle is being inserted into my leg ...
... I have a thousand splinters under my skin ...
Very often, pain can be caused by something that in normal conditions does not cause pain: by touching clothes, sheets, blankets, etc. Sometimes the pain can be spontaneous and very severe. But the problem is that it is "invisible." Unlike trauma or arthritis, you do not see its cause, and it is difficult to understand what it is connected with.
Neuropathic pain disrupts everyday life
If neuropathic pain is treated improperly, it can lead to a significant disruption of everyday life. An ordinary walk to the store can be a torment. Even the process of dressing or wearing clothes, a touch of bed linen can be accompanied by severe burning pains.
... I can do nothing without feeling pain. I am not sleeping. No one in my family knows what suffering I go through every day ...
Many people with neuropathic pain cannot sleep well and are not able to work. They stop believing in getting rid of these pains, lose hope and become depressed. They prefer not to leave the house, communicate less with family members and friends.
The most frequent options for neuropathic pain
Neuropathic pain due to diabetic nerve damage
Nerve damage in diabetes is called diabetic polyneuropathy. Especially often it develops with a high content of glucose in the blood. Nearly half of patients with diabetic polyneuropathy have neuropathic pains, which include:
- tingling in feet, toes
- burning in the feet, worse at night
- pain when wearing shoes and / or standing and walking
Neuropathic pain due to herpes infection
The pain that occurs after herpes zoster is called postherpetic neuralgia. It develops more often in older people after the disappearance of the characteristic rash. It can last 3 months or more and is characterized by:
- burning pains in the area where there were rashes
- pain when touching clothes, bedding
- long course, sleep disturbance
Neuropathic pain after spinal cord injury
After a spinal cord injury, patients may experience severe pain. Often they are associated with damage to the nerves that pass through the spinal cord, and belong to the neuropathic type of pain. These are burning, stabbing, shooting pains in the arms, legs, torso, sometimes very strong.
Neuropathic pain after stroke
Approximately in 8% of patients who have had a stroke, after some time (from 1 month to 2 years), discomfort in the form of tingling, burning, pain upon contact with cold objects may appear on the affected side, “The hand is cold”. Therefore, to reduce pain, some patients wear mittens. This type of neuropathic pain is called post-stroke central pain. It is caused by damage to the nerves in the brain.
Neuropathic pain after surgery
After surgery, some patients have been suffering from pain and discomfort during burning for a long time, tingling, "chills" in the area of postoperative suture. This is due to partial damage to the peripheral nerves in the surgical area. Such neuropathic pains often occur after breast surgery (mastectomy), etc.
Neuropathic back pain
Each of us, one way or another, sometimes has a backache. Most often this is due to muscle tension, changes in the joints of the vertebrae. But if there is a compression of the nerve roots emerging from the spine (for example, a herniated disc), neuropathic pain can occur: sharp shooting pains from the loins to the toes, in combination with a burning sensation, tingling and numbness in the leg. Sometimes these pains pass quickly, but in some patients it may persist for a long time and cannot be treated by usual methods of pain relief.
Neuropathic facial pain
Neuropathic pain can occur in the form of seizures. For example, some older and older people while having a conversation, eating, or touching their face have bouts of severe pain in half of the face. This is due to the compression of the trigeminal nerve, which is responsible for the sensitivity in the facial area. The cause of compression is most often a nearby blood vessel. This disease is called trigeminal neuralgia. Attacks of pain are very painful, can last for years, violate the human performance.
Take the first step to relieve the pain
There are different ways to treat neuropathic pain. But at the same time, you should actively participate in the treatment process and, along with the doctor, be responsible for its results. Already half the work will be done if you are active and start helping yourself.
What do I need to do ?
► Tell your doctor about pain and discuss the best treatment for you.
► Find out what special medicines are available for the treatment of neuropathic pain.
► Try to discuss with your doctor all aspects of the upcoming treatment: duration, effectiveness, combination of drugs, side effects, etc.
► Consider the possibility of doing a moderate exercise program for yourself.
► Try to master relaxation techniques.
► Ask family members, friends to help you with the treatment.
The treatment uses an integrated approach - psychotherapy, physiotherapy and pharmacotherapy.
In pharmacotherapy, anticonvulsants (gabapentin (Neurontin), pregabalin (Lyricum), classical tricyclic (amitriptyline) , and newer ones - noradrenaline reuptake inhibitors and serotonin (duloxetine, venlafaxine) are primarily used.
To eliminate peripheral pain, lidocaine is recommended in the form of creams or plates (Versatis). The course of treatment depends on the clinical form and can vary from 1 to 6 months.
Thus, the treatment of neuropathic pain currently remains a challenge. The above principles and algorithms of treatment can help the doctor to carry out the most effective and safe treatment of patients with neuropathic pain syndrome. In the future, success and prospects of treatment are associated with the development of drugs that affect the specific pathophysiological mechanisms of this syndrome.
Neuropathic pain is a pain syndrome caused by damage to the somatosensory nervous system due to a variety of reasons, see Table 1.
The most recognized in the treatment of neuropathic pain today is pharmacotherapy. The main drugs and their characteristics are shown in Table 2.
Table 3 lists the recommendations of the European Federation of Neurological Societies (EFNS) for the treatment of certain conditions involving neuropathic pain. The experts of this federation analyzed all clinical studies on neuropathic pain registered in the Cochrane Library (database of evidence-based clinical studies) since 1966. As a result, studies with a high level of evidence were selected, and on their basis, European recommendations for pharmacotherapy were built.
To date, it is not known whether the ineffectiveness of one drug is a predictor of the ineffectiveness of another or of all subsequent drug therapy. In the event that the first prescribed drug was ineffective or poorly tolerated by the patient, one should switch to alternative monotherapy with the first-line drug (Fig. 1). If all the first-line drugs were ineffective or poorly tolerated, then it is recommended to start monotherapy with tramadol or its combination with paracetamol or an opioid analgesic. Unfortunately, this is not always possible, since the prescription of opioid drugs is limited by the special requirements for the discharge of these drugs.
Analysis of pain syndrome from the point of view of its pathophysiological mechanisms (nociceptive, neuropathic, mixed) turned out to be very important primarily from the point of view of treatment. If the doctor assesses pain as nociceptive, then simple analgesics and NSAIDs will be the best means to treat it. If the pain is neuropathic or if there is a neuropathic component, then the drugs of choice are anticonvulsants (pregabalin), antidepressants, opioid analgesics and lidocaine, the features of which were discussed above (Fig. 2).
In the case of mixed pain syndromes, combination therapy with the choice of agents is possible depending on the representation of the nociceptive and neuropathic components (Fig. 3).
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