What is neuropathic pain?
Neuropathic pain is a kind of pain that, unlike ordinary pain, does not result from a reaction to physical damage, but from the pathological excitation of neurons in the peripheral or central nervous system responsible for the reaction to physical damage to the body (ordinary pain).
Neuropathic pain can be associated with abnormal sensations (dysesthesia) or pain caused by stimuli that normally do not cause pain (allodynia). It can be permanent and / or episodic. The latter is piercing or similar to electric shocks. Common qualities include burning or cold, sensations of creepy and needles, numbness and itching. The cause of neuropathic pain can be pathological processes in the peripheral and central nervous system. Thus, distinguish peripheral neuropathy, neuropathic pain of central and mixed genesis. Neuropathic pain affects 7-8% of Europe's population, and in 5% of people it can be severe.
Neuropathic pain, as a rule, has a chronic course.
For subjective characteristics of ND patients use such definitions as burning, stitching, 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 symptoms (hypesthesia, gipalgesia) of loss of function of damaged structures. The NB is characterized by a combination of positive and negative symptoms, which varies among the same patient during the course of the disease.
Very characteristic of the neuropathic type of pain is the phenomenon of allodynia - the emergence of pain in response to a stimulus, which in healthy people does not cause it. In such cases, patients experience severe pain at the slightest touch, sometimes even with the wind blowing.
There are temperature and mechanical allodynia. The mechanical is divided into a static one, which appears at a pressure on a fixed point of the skin, and dynamic, which occurs when moving stimuli (skin irritation with a brush or a finger).
With hyperalgesia, the sensitivity to the pain stimulus is significantly higher than expected in normal. With hyperpathy, the subjective response to both pain and neurological stimuli is excessive and often persists for a long time after the cessation of irritation. Feelings of tickling, painless tingling and other similar sensations are related to paresthesia; if these feelings cause pain, they are called dysesthesias. 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 wearing a lancinating character, combined with allodynia and hyperpathy and often accompanied by vascular and trophic disorders. The combination of burning pain with severe trophic disorders, as well as the effectiveness in some cases of sympathetic blockades, served as a pretext for the sympathetic nervous system to participate in the formation of this pain. Such a pain is also called sympathetically sustained pain.
The clinical signs of the National Bank are
- absence of a cause for direct irritation of nociceptors on the periphery (trauma, inflammation, ischemia);
- persistent, prolonged pain;
- ineffectiveness of analgesics for pain relief;
- localization of pain in the zone of sensory defect, corresponding to the defeat of any department of the nervous system;
- presence of stimulo-dependent painful phenomena - allodynia, hyperalgesia, hyperesthesia, hyperpathy;
- combination with vegetative disorders in the field of pain in the form of reduced blood flow, hyper or hypohidrosis, etc .;
- combination with motor disorders;
- frequent deterioration of well-being at night.
In patients' complaints pathognomonic pain descriptors are the following definitions: burning, shooting, pulling, cutting or comparable to the sense of passing an electric current.
For the NB, comorbid disorders are characteristic, in particular, sleep disorders, 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 condition in NB. Patients with chronic pain usually experience anxiety as a result of stress from life with pain. Pain can cause changes in the level of anxiety, and increased anxiety can increase the perception of pain.
Neuropathic pain of the central genesis is observed with spinal cord injuries, multiple sclerosis, sometimes with strokes. In addition to diabetes, the most frequent causes of pain in peripheral neuropathy are herpesvirus infection, HIV-associated neuropathy, lack of certain nutrients, toxins, paraneoplastic syndrome, immune system disorders, trauma to nerve trunks. Peripheral polyneuropathy is the most frequent symptom of Fabry's disease.
Neuropathic pain is common in cancer; it is caused by the direct action of the tumor on the peripheral nerves (for example, by compression) or as a side effect of chemotherapy, radiotherapy or surgery.
Characteristic sensations in neuropathic pain
- The passage of electric current
- Shooting pains
- "Crawling crawl"
These pains are common
We are all familiar with the pain - be it headache, toothache or muscle pain after physical exertion. But there is a very different pain, which is associated with the defeat of nerves. It is she who often becomes painful, violates a person's life for many months or years. This pain is called neuropathic.
.. It seemed to me stupid to go to see a doctor about numbness in my feet. I would like to know before that it turns out to be a neuropathic pain and it can be treated ..
It occurs in 6-7 out of 100 people. Neuropathic pain can make the performance of even the most elementary actions, such as dressing socks, a shirt, walking, impossible. Often people do not understand what kind of pain and how to tell a doctor about it. They can not find the words to describe it. Therefore, often these patients do not receive proper care and treatment.
How does neuropathic pain occur?
In our body, there are millions of nerves interacting with each other. Together they form a 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 hot sand, the nerves on the foot send a signal to the brain telling you that you are stepping on something hot. As a result, you feel a burning sensation in the foot. Or, if you accidentally touch a bare electrical wire, the nerves on your hand send a quick signal to your brain that you were electrocuted.
But if there is damage to the nerves, they start to work incorrectly and send the wrong signals to the brain. For example, damaged nerves can tell the brain that you stepped on hotter or touched an electric wire. And this despite the fact that in fact you did not step on anything and did not touch anything. Nerves can be damaged as a result of many causes, such as diabetes mellitus, herpes infection, hand and foot injuries, spinal disorders, strokes, oncological diseases, etc.
Neuropathic pain is like ...
Many people who have neuropathic pain often do not describe their feelings as pain. On the contrary, they can tell that they feel "a lot of needles, splinters", "goose bumps", tingling, numbness, feel "the passage of an electric current".
... I felt that I was walking on broken glass ...
... As if I were being injected into the leg with a hot needle ...
... I have a thousand splinters under my skin ...
Very often, pain can be caused by something that under normal conditions does not cause pain: by touching clothes, sheets, blankets, etc. Sometimes the pain can be spontaneous and very strong. But the problem is that it is "invisible". Unlike a trauma or arthritis, you do not see its cause, and it is difficult to understand what it is related to.
Neuropathic pain disrupts everyday life
If neuropathic pain is treated incorrectly, it can lead to a significant disruption of daily life. A normal walk into the store can become a torture. Even the process of dressing or wearing clothes, touching bed linen can be accompanied by pronounced burning pains.
... I can not do anything without experiencing pain. I am not sleeping. No one in my family knows what suffering I'm going through every day ...
Many people suffering from neuropathic pain can not sleep well and are unable to work. They stop believing in getting rid of these pains, lose hope and become depressed. They prefer not to leave the house, less communicate with family members and friends.
The most frequent variants of neuropathic pain
Neuropathic pain due to diabetic nerve damage
The defeat of the nerves in diabetes is called diabetic polyneuropathy. Especially often it develops at a high glucose level in the blood. Almost half of patients with diabetic polyneuropathy have neuropathic pains, which include:
- tingling in feet, toes
- burning sensation 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 the elderly after the disappearance of a characteristic rash. It can last 3 months or more and is characterized by:
- burning pain in the area where there were rashes
- pain when touching clothes, bed linen
- prolonged course, sleep disturbance
Neuropathic pain after spinal cord injury
After a spinal cord injury, patients may be disturbed by severe pain. Often they are associated with damage to the nerves passing in the spinal cord, and are related to the neuropathic type of pain. This burning, stitching, shooting pain in the hands, legs, trunk, sometimes very strong.
Neuropathic pain after a stroke
Approximately 8% of patients who underwent cerebral stroke after a period of time (from 1 month to 2 years) on the affected side, or in the arm and / or leg, may experience unpleasant sensations in the form of tingling, burning, pain in contact with cold objects, "The hand is freezing." Therefore, to reduce the pain, some patients wear mittens. This type of neuropathic pain is called post-stroke central pain. Its cause is the defeat of the nerves in the brain.
Neuropathic pain after surgery
After surgery, some patients for a long time are concerned about pain and unpleasant sensations of burning, tingling, "chills" in the postoperative suture zone. This is due to the partial damage of the peripheral nerves in the field of surgical intervention. Such neuropathic pains often occur after operations to remove the mammary gland (mastectomy), etc.
Neuropathic back pain
Each of us, somehow, sometimes has a backache. More often it is due to muscle tension, changes in joints of the vertebrae. But if there is a compression of the nerve roots leaving the spine (for example, a herniated intervertebral disc), then neuropathic pain may arise: acute shooting pain from the waist to the toes, combined with a burning sensation, tingling and numbness in the leg. Sometimes these pains pass quickly, but some patients may persist for a long time and do not succumb to the usual methods of anesthesia.
Neuropathic pain in the face
Neuropathic pain can occur as seizures. For example, in some older and older people, during a conversation, eating, or when you touch a person, there are seizures of severe pain in half of the face. This is due to compression of the trigeminal nerve, which is responsible for sensitivity in the face. 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, disrupt the working capacity of a person.
Take the first step to getting rid of pain
There are different ways of treating neuropathic pain. But at the same time you must actively participate in the treatment process and be along with the doctor responsible for its results. Already half of the case will be done if you are active and start helping yourself.
What do I need to do ?
► Tell your doctor about the pain and discuss - which treatment will be best for you.
► Find out what special medicines are available to treat neuropathic pain.
► Try to discuss with the doctor all aspects of the forthcoming treatment: duration, effectiveness, combination of drugs, side effects, etc.
► Consider for yourself the possibility of doing a moderate exercise program.
► Try to learn the methods of relaxation.
► Ask family members and friends to help you with the treatment.
The treatment uses a complex approach - psychotherapy, physiotherapy and pharmacotherapy.
In pharmacotherapy, anticonvulsants (gabapentin (Neurontin), pregabalin (lyric), classical tricyclic (amitriptyline) , and newer inhibitors of norepinephrine and serotonin reuptake (duloxetine, venlafaxine) are primarily used.
To eliminate peripheral pain, recommend lidocaine 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 is currently a difficult task. The above principles and algorithms of treatment can help a doctor to perform the most effective and safe treatment of patients with neuropathic pain syndrome. In the future, success and prospects for 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 the defeat of the somatosensory nervous system due to a variety of causes, see Table 1.
The most recognized in the treatment of neuropathic pain today is pharmacotherapy. The main preparations and their characteristics are given in Table 2.
Table 3 shows the recommendations of the European Federation of Neurological Societies (EFNS) on the therapy of certain conditions accompanied by neuropathic pain. The experts of this federation conducted an analysis of all clinical studies on neuropathic pain recorded in the Cochrane Library (a database of evidence-based clinical trials) since 1966. As a result, studies were selected with a high level of evidence, and on their basis European recommendations on pharmacotherapy were built.
To date, it is not known whether the inefficiency of one drug is a predictor of the ineffectiveness of another or all subsequent drug therapy. In the event that the first prescribed drug was ineffective or poorly tolerated by the patient, you should switch to alternative monotherapy with the first-line drug (Figure 1). If all first-line drugs are ineffective or poorly tolerated, it is recommended to start monotherapy with tramadol or a combination of it with paracetamol or an opioid analgesic. Unfortunately, this is not always possible, since the prescription of opioid drugs is limited by special requirements for the discharge of these drugs.
The analysis of the pain syndrome in terms of its pathophysiological mechanisms (nociceptive, neuropathic, mixed) was very important primarily from the point of view of treatment. If the doctor evaluates the pain as a nociceptive, then the best means for its treatment will be simple analgesics and NSAIDs. If the pain is neuropathic or there is a neuropathic component, the drugs of choice are anticonvulsants (pregabalin), antidepressants, opioid analgesics and lidocaine, the characteristics of which have been discussed above (Figure 2).
In the case of mixed pain syndromes, combination therapy with a choice of agents is possible, depending on the representation of the nociceptive and neuropathic components (Figure 3).
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