Pain. Causes of pain, how is pain formed? What structures and substances form the sensation of pain. Pain - definition and types, classification and types of pain

What do you know about pain and painful sensations? Do you know how the perfect pain mechanism works?

How does pain occur?

Pain, for many, is a complex experience consisting of a physiological and psychological response to a noxious stimulus. Pain is a warning mechanism that protects the body by influencing it to withdraw from harmful stimuli. It is primarily associated with injury or threat of injury.

Pain is subjective and difficult to quantify because it has both an emotional and sensory component. Although the neuroanatomical basis for the sensation of pain develops before birth, individual pain responses develop during early childhood and, in particular, are influenced by social, cultural, psychological, cognitive and genetic factors. These factors explain differences in pain tolerance among people. For example, athletes may resist or ignore pain while playing sports, and some religious practices may require participants to endure pain that seems unbearable to most people.

Pain sensations and pain function

An important function of pain is to warn the body of possible damage. This is achieved through nociception, the neural processing of noxious stimuli. Painful sensation, however, is only one part of the nociceptive response, which may include increased blood pressure, increased heart rate, and reflexive withdrawal from the noxious stimulus. Acute pain may result from breaking a bone or touching a hot surface.

During acute pain, an immediate intense sensation of short duration, sometimes described as a sharp, startling sensation, is accompanied by a dull throbbing sensation. Chronic pain, which is often associated with diseases such as cancer or arthritis, is more difficult to find and treat. If the pain cannot be alleviated, psychological factors such as depression and anxiety can worsen the condition.

Early concepts of pain

The concept of pain is that pain is a physiological and psychological element of human existence and thus it has been known to mankind since the earliest eras, but the ways in which people react and understand pain vary greatly. In some ancient cultures, for example, pain was deliberately inflicted on people as a means of appeasing angry gods. Pain was also seen as a form of punishment inflicted on people by gods or demons. IN Ancient China pain was considered to be the cause of an imbalance between the two complementary forces of life, yin and yang. The ancient Greek physician Hippocrates believed that pain was associated with too much or too little of one of the four spirits (blood, phlegm, yellow bile or black bile). The Muslim physician Avicenna believed that pain is a sensation that arose with a change physical condition bodies.

Mechanism of pain

How does the pain mechanism work, where does it turn on and why does it go away?

Theories of pain
Medical understanding of the mechanism of pain and the physiological basis of pain is a relatively recent development, beginning in earnest in the 19th century. At that time, various British, German and French doctors recognized the problem of chronic "pain without lesions" and explained them functional disorder or constant irritation of the nervous system. Another of the creative etiologies proposed for pain was the German physiologist and anatomist Johannes Peter Müller's "Gemeingefühl", or "cenesthesis", the human ability to correctly perceive internal sensations.

American physician and author S. Weir Mitchell studied the mechanism of pain and observed soldiers civil war suffering from causalgia (constant burning pain, later called complex regional pain syndrome), phantom limb pain, and others painful conditions after their initial wounds had healed. Despite the strange and often hostile behavior of his patients, Mitchell was convinced of the reality of his physical suffering.

By the late 1800s, the development of specific diagnostic tests and the identification specific signs pain began to redefine the practice of neurology, leaving little room for chronic pain that could not be explained in the absence of other physiological symptoms. At the same time, practitioners of psychiatry and the emerging field of psychoanalysis discovered that "hysterical" pain offered potential insight into mental and emotional states. Contributions from individuals such as the English physiologist Sir Charles Scott Sherrington supported the concept of specificity, according to which "real" pain was a direct individual response to a specific noxious stimulus. Sherrington coined the term "nociception" to describe the response of pain to such stimuli. Specificity theory suggested that people who reported pain in the absence of obvious reason, were delusional, neurotically obsessive, or malingering (often a finding of military surgeons or those handling workers' compensation cases). Another theory that was popular among psychologists at the time but was soon abandoned was the intensity theory of pain, in which pain was considered an emotional state caused by unusually intense stimuli.

In the 1890s, German neurologist Alfred Goldscheider, who was studying the mechanism of pain, endorsed Sherrington's insistence that the central nervous system integrates input from the periphery. Goldscheider proposed that pain results from the brain's recognition of spatial and temporal patterns of sensation. French surgeon René Lehrich, who worked with casualties during World War I, theorized that nerve injury, which damages the myelin sheath surrounding the sympathetic nerves (the nerves involved in the response), can lead to sensations of pain in response to normal stimuli and internal physiological activity. American neurologist William C. Livingston, who worked with patients with work-related injuries in the 1930s, developed a feedback circuit in nervous system, which he called a “vicious circle.” Livingston proposed that severe, long-term pain causes functional and organic changes in the nervous system, thereby creating a chronic pain state.

However, the various theories of pain were largely ignored until World War II, when organized groups of doctors began to observe and treat large numbers of people with similar injuries. In the 1950s American anesthesiologist Henry C. Beecher, using his experience with civilian patients and wartime casualties, found that soldiers with severe wounds often fared much less well than civilian surgical patients. Beecher concluded that pain is the result of a fusion of physical sensations with a cognitive and emotional “reactionary component.” Thus, the mental context of pain is important. Pain for a surgical patient meant impairment normal life and fears of serious illness, while pain for wounded soldiers meant liberation from the battlefield and increased chance for survival. Therefore, the assumptions of specificity theory, based on laboratory experiments in which the response component was relatively neutral, could not be applied to the understanding of clinical pain. Beecher's findings were supported by the work of American anesthesiologist John Bonica, who in his book The Management of Pain (1953) believed that clinical pain included both physiological and psychological components.

Dutch neurosurgeon Willem Nordenbos expanded the theory of pain as the integration of multiple inputs to the nervous system in his short but classic book Pain (1959). Nordenbos' ideas appealed to Canadian psychologist Ronald Melzack and British neurologist Patrick David Wall. Melzack and Stena combined the ideas of Goldscheider, Livingston and Nordenbos with available research data, and in 1965 they proposed the so-called pain theory of pain management. According to gate control theory, the perception of pain depends on nervous mechanism in the substantial gelatinous layer of the dorsal horn of the spinal cord. The mechanism acts as a synaptic gate that modulates the sensation of pain from myelinated and unmyelinated peripheral nerve fibers and the activity of inhibitory neurons. Thus, stimulation of nearby nerve endings may inhibit nerve fibers that transmit pain signals, which explains the relief that can occur when the injured area is stimulated by pressure or friction. Although the theory itself turned out to be incorrect, it was implied that laboratory and clinical observations may demonstrate a physiological basis complex mechanism neural integration for pain perception, inspiring and challenging a younger generation of researchers.

In 1973, building on the surge of interest in pain caused by Walls and Melzack, Bonica organized a meeting between interdisciplinary pain researchers and clinicians. Under Bonica's leadership, the conference, which took place in the United States, gave birth to an interdisciplinary organization known as the International Association for the Study of Pain (IASP) and a new journal called Pain, originally edited by Wall. The formation of the IASP and the launch of the journal marked the emergence of pain science as a professional field.

In subsequent decades, pain research has expanded significantly. Two important conclusions emerged from this work. First, it has been found that severe pain from injury or other stimulus, if continued over a period of time, alters the neurosurgery of the central nervous system, thereby sensitizing it and leading to neuronal changes that are carried out after the original stimulus is removed. This process is perceived as chronic pain for the affected person. Many studies have demonstrated the involvement of neuronal changes in the central nervous system in the development of chronic pain. In 1989, for example, American anesthesiologist Gary J. Bennett and Chinese scientist Xie Yikuan demonstrated the neural mechanism underlying this phenomenon in rats with constrictive ligatures located loosely around sciatic nerve. In 2002, Chinese neurologist Min Zhuo and colleagues reported the identification of two enzymes, adenylyl cyclase type 1 and 8, in mouse forebrains that play an important role in sensitizing the central nervous system to painful stimuli.

The second finding that emerged was that pain perception and response differed by gender and ethnicity, as well as by training and experience. Women appear to suffer pain more often and with more emotional distress than men, but some evidence suggests that women can cope with severe pain more effectively than men. African Americans demonstrate higher vulnerability to chronic pain and higher rates of disability than white patients. These observations are confirmed by neurochemical studies. For example, in 1996, a group of researchers led by American neuroscientist John Levine reported that different types of opioid drugs provided different levels of pain relief in women and men. Other studies in animals have suggested that pain early in life may cause neuronal changes at the molecular level that affect how a person responds to pain as an adult. A significant finding from these studies is that no two patients experience pain in the same way.

Physiology of pain

Although subjective, most pain is related to tissue damage and has a physiological basis. However, not all tissues are susceptible to the same type of injury. For example, although the skin is sensitive to burning and cutting, visceral organs can be cut without causing pain. However, excessive stretching or chemical irritation of the visceral surface will cause pain. Some tissues do not cause pain no matter how they are stimulated; the liver and alveoli of the lungs are insensitive to almost every stimulus. Thus, tissues respond only to specific stimuli that they may encounter and are generally impervious to all types of damage.

Mechanism of pain

Pain receptors, located in the skin and other tissues, are nerve fibers with endings that can be excited by three types of stimuli - mechanical, thermal and chemical; some endings respond primarily to one type of stimulation, whereas other endings can detect all types. Chemicals produced by the body that stimulate pain receptors include bradykinin, serotonin and histamine. Prostaglandins are fatty acids that are released during inflammation and can increase the sensation of pain by sensitizing nerve endings; that increased sensitivity is called hyperalgesia.

The biphasic experience of acute pain is mediated by two types of primary afferent nerve fibers that transmit electrical impulses from tissues to the spinal cord through ascending nerve pathways. Delta A fibers are the larger and more rapidly conducting of the two types due to their thin myelin coating, and are therefore associated with sharp, well-localized pain that first occurs. Delta fibers are activated by mechanical and thermal stimuli. Smaller, unmyelinated C fibers respond to chemical, mechanical, and thermal stimuli and are associated with a lingering, poorly localized sensation that follows the first rapid sensation of pain.

Pain impulses penetrate the spinal cord, where they synapse mainly on dorsal horn neurons in the marginal zone and substantial gelatinoses of the gray matter of the spinal cord. This area is responsible for regulating and modulating incoming impulses. Two different pathways, the spinothalamic and spinoreticular tracts, carry impulses to the brain and thalamus. The spinothalamic input is thought to influence the conscious experience of pain, and the spinoreticular tract is thought to produce the arousal and emotional aspects of pain.

Pain signals can be selectively inhibited in the spinal cord through a descending pathway that originates in the midbrain and ends in the dorsal horn. This analgesic (pain-relieving) response is controlled by neurochemicals called endorphins, which are opioid peptides such as enkephalins that are produced by the body. These substances block the reception of painful stimuli by binding to neural receptors that activate the pain-relieving neural pathway. This system can be activated by stress or shock and is likely responsible for the absence of pain associated with severe trauma. This may also explain people's different abilities to perceive pain.

The origin of pain signals may be unclear to the sufferer. Pain that originates from deep tissues but is “felt” in superficial tissues is called pain. Although the exact mechanism is unclear, this phenomenon may result from the convergence of nerve fibers from different tissues onto the same part of the spinal cord, which may allow nerve impulses from one pathway to travel to other pathways. Phantom limb pain is an amputee who experiences pain in her missing limb. This phenomenon occurs because the nerve trunks that connect the now missing limb to the brain still exist and are capable of firing. The brain continues to interpret stimuli from these fibers as coming from what it previously learned was a limb.

Psychology of pain

The perception of pain arises from the brain processing new sensory input with existing memories and emotions, just like other perceptions. Childhood experience, cultural attitudes, heredity, and gender are factors that contribute to each individual's development of perception and response to different types of pain. Although some people can physiologically withstand pain better than others, cultural factors, rather than heredity, usually explain this ability.

The point at which a stimulus begins to become painful is the pain threshold; Most studies have found that views are relatively similar among disparate groups of people. However, the pain tolerance threshold, the point at which pain becomes unbearable, varies significantly among these groups. A stoic, unemotional response to trauma may be a sign of courage in certain cultural or social groups, but this behavior may also mask the severity of the injury to the treating physician.

Depression and anxiety can lower both types of pain thresholds. Anger or worry, however, can temporarily ease or lessen the pain. Feelings of emotional relief can also reduce painful sensations. The context of the pain and the meaning it has for the sufferer also determines how the pain is perceived.

Pain relief

Attempts to relieve pain usually involve both physiological and psychological aspects pain. For example, reducing anxiety may reduce the amount of medication needed to relieve pain. Acute pain is usually the easiest to control; medications and rest are often effective. However, some pain may defy treatment and persist for many years. Such chronic pain can be exacerbated by hopelessness and anxiety.

Opiates are powerful painkillers and are used to treat severe pain. Opium, a dried extract obtained from the immature sawdust of the opium poppy (Papaver somniferum), is one of the oldest analgesics. Morphine, a powerful opiate, is an extremely effective pain reliever. These narcotic alkaloids mimic the endorphins produced by naturally by the body, binding to their receptors and blocking or reducing the activation of pain neurons. However, the use of opioid painkillers should be monitored not only because they are addictive substances, but also because the patient may develop tolerance to them and may require gradually more high doses to achieve the desired level of pain relief. Overdose may cause potentially fatal respiratory depression. Other significant side effects, such as nausea and psychological depression upon withdrawal, also limit the usefulness of opiates.

Willow bark extracts (genus Salix) contain the active ingredient salicin and have been used since ancient times to relieve pain. Modern non-arcotic anti-inflammatory analgesic salicylates such as aspirin (acetylsalicylic acid) and other anti-inflammatory analgesics such as acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs, such as ibuprofen), and cyclooxygenase (COX) inhibitors (such as celecoxib) are less effective than opiates. but are not additive. Aspirin, NSAIDs, and COX inhibitors either nonselectively or selectively block the activity of COX enzymes. COX enzymes are responsible for converting arachidonic acid (a fatty acid) into prostaglandins, which increases sensitivity to pain. Acetaminophen also prevents the formation of prostaglandins, but its activity appears to be limited primarily to the central nervous system and may occur through multiple mechanisms. Drugs known as N-methyl-d-aspartate receptor (NMDAR) antagonists, examples of which include dextromethorphan and ketamine, can be used to treat certain forms of neuropathic pain, such as diabetic neuropathy. The drugs work by blocking NMDARs, whose activation is involved in nociceptive transmission.

Psychotropic medications, including antidepressants and tranquilizers, may be used to treat patients with chronic pain who also suffer from psychological states. These medications help reduce anxiety and sometimes change the perception of pain. Pain appears to be relieved by hypnosis, placebos, and psychotherapy. Although the reasons why an individual might report pain relief after taking a placebo or after psychotherapy remains unclear, researchers suspect that the expectation of relief is stimulated by the release of dopamine in an area of ​​the brain known as the ventral striatum. Activity in the abdominal genital organ is associated with increased activity dopamine and is associated with the placebo effect, in which pain relief is reported after placebo treatment.

Specific nerves may be blocked in cases where the pain is limited to an area that has little sensory nerves. Phenol and alcohol are neurolytics that destroy nerves; Lidocaine can be used for temporary pain relief. Surgery department nerve surgery is rarely performed because it can cause serious side effects such as motor loss or relaxed pain.

Some pain may be treated through transcutaneous electrical nerve stimulation (TENS), in which electrodes are placed on the skin over painful area. Stimulation of additional peripheral nerve endings has an inhibitory effect on the nerve fibers that cause pain. Acupuncture, compresses and heat treatments can work by the same mechanism.

Chronic pain, defined broadly as pain that persists for at least six months, represents the biggest challenge in pain management. Incapable chronic discomfort may cause psychological complications, such as hypochondria, depression, sleep disturbances, loss of appetite and feelings of helplessness. Many patient clinics offer a multidisciplinary approach to chronic pain management. Patients with chronic pain may require unique pain management strategies. For example, some patients may benefit from a surgical implant. Examples of implants include intrathecal drug delivery, in which a pump implanted under the skin delivers pain medication directly to the spinal cord, and a spinal cord stimulation implant, in which an electrical device placed in the body sends electrical impulses to the spinal cord to inhibit pain signaling. Other treatment strategies for chronic pain include alternative therapy, physical exercise, physical therapy, cognitive behavioral therapy and TENS.

Chapter 2. Pain: from pathogenesis to choice of drug

Pain is the most common and subjectively difficult complaint of patients. In 40% of all initial visits to a doctor, pain is the leading complaint. The high prevalence of pain syndromes results in significant material, social and spiritual losses.

As mentioned above, the classification committee of the International Association for the Study of Pain defines pain as “an unpleasant sensory and emotional experience associated with an existing or possible damage tissue or described in terms of such damage." This definition emphasizes that the sensation of pain can occur not only when tissue is damaged, but even in the absence of any damage, which indicates the important role of mental factors in the formation and maintenance of pain.

Classification of pain

Pain is a clinically and pathogenetically complex and heterogeneous concept. It varies in intensity, localization and in its subjective manifestations. The pain can be shooting, pressing, throbbing, cutting, as well as constant or intermittent. The entire existing variety of characteristics of pain is largely related to the very cause that caused it, the anatomical region in which the nociceptive impulse occurs, and is very important for determining the cause of pain and subsequent treatment.

One of the most significant factors in understanding this phenomenon is the division of pain into acute and chronic (Fig. 8).

Acute pain- this is a sensory reaction with the subsequent inclusion of emotional, motivational, vegetative and other factors when the integrity of the body is violated. The development of acute pain is associated, as a rule, with very specific painful irritations of superficial or deep tissues and internal organs, and dysfunction of smooth muscles. Spicy pain syndrome develops in 80% of cases, has a protective, preventive value, as it indicates “damage” and forces a person to take measures to find out the cause of the pain and eliminate it. The duration of acute pain is determined by the recovery time of damaged tissues and/or impaired smooth muscle function and usually does not exceed 3 months. Acute pain is usually well controlled with analgesics.

In 10–20% of cases, acute pain becomes chronic, which lasts more than 3–6 months. However, the main difference between chronic pain and acute pain is not the time factor, but qualitatively different neurophysiological, psychophysiological and clinical relationships. Chronic pain is not protective. In recent years, chronic pain has begun to be considered not only as a syndrome, but also as a separate nosology. Its formation and maintenance depends to a greater extent on a complex of psychological factors rather than on the nature and intensity of the peripheral nociceptive effect. Chronic pain may persist after the healing process has completed, i.e. exist regardless of damage (presence of nociceptive effects). Chronic pain is not relieved by analgesics and often leads to psychological and social maladaptation of patients.

One of the possible reasons contributing to the chronicity of pain is treatment, inadequate reason and pathogenesis of pain syndrome. Eliminating the cause of acute pain and/or treating it as effectively as possible is the key to preventing the transformation of acute pain into chronic pain.

Important for successful treatment pain has a definition of its pathogenesis. Most common nociceptive pain, which occurs when irritation of peripheral pain receptors - “nociceptors”, localized in almost all organs and systems (coronary syndrome, pleurisy, pancreatitis, gastric ulcer, renal colic, articular syndrome, damage to the skin, ligaments, muscles, etc.). Neuropathic pain occurs due to damage to various parts (peripheral and central) of the somatosensory nervous system.

Nociceptive pain syndromes are most often acute (burn, cut, bruise, abrasion, fracture, sprain), but can also be chronic nature(osteoarthritis). With this type of pain, the factor that caused it is usually obvious, the pain is usually clearly localized (usually in the area of ​​injury). When describing nociceptive pain, patients most often use the terms “squeezing”, “aching”, “pulsating”, “cutting”. In the treatment of nociceptive pain, a good therapeutic effect can be obtained by prescribing simple analgesics and NSAIDs. When the cause is eliminated (cessation of irritation of the “nociceptors”), nociceptive pain goes away.

Neuropathic pain can be caused by damage to the afferent somatosensory system at any level, from the peripheral sensory nerves to the cortex cerebral hemispheres, as well as disturbances in descending antinociceptive systems. When the peripheral nervous system is damaged, the pain is called peripheral; when the central nervous system is damaged, it is called central (Fig. 9).

Neuropathic pain, which occurs when various parts of the nervous system are damaged, is characterized by patients as burning, shooting, cooling and is accompanied by objective symptoms of nerve irritation (hyperesthesia, paresthesia, hyperalgesia) and/or dysfunction (hypesthesia, anesthesia). A characteristic symptom of neuropathic pain is allodynia, a phenomenon characterized by the occurrence of pain in response to a non-painful stimulus (stroking with a brush, cotton wool, temperature factor).

Neuropathic pain is characteristic of chronic pain syndromes of various etiologies. At the same time, they are united by common pathophysiological mechanisms formation and maintenance of pain.

Neuropathic pain is difficult to treat with standard analgesics and NSAIDs and often leads to severe maladjustment in patients.

In the practice of a neurologist, traumatologist, and oncologist, pain syndromes occur, in clinical picture in which symptoms of both nociceptive and neuropathic pain are observed - “mixed pain” (Fig. 10). This situation can occur, for example, when a tumor compresses a nerve trunk, irritation from a spinal nerve herniation (radiculopathy), or when a nerve is compressed in a bone or muscle canal ( tunnel syndromes). In the treatment of mixed pain syndromes, it is necessary to influence both, nociceptive and neuropathic, components of pain.

Nociceptive and antinociceptive systems

Today's ideas about the formation of pain are based on the idea of ​​the existence of two systems: nociceptive (NS) and antinociceptive (ANS) (Fig. 11).

The nociceptive system (is ascending) ensures the transmission of pain from peripheral (nociceptive) receptors to the cerebral cortex. The antinociceptive system (which is descending) is designed to control pain.

At the first stage of pain formation, pain (nociceptive) receptors are activated. Activation of pain receptors can result, for example, inflammatory process. This causes pain impulses to be transmitted to the dorsal horns of the spinal cord.

At the segmental spinal level, modulation of nociceptive afferentation occurs, which is carried out by the influence of descending antinociceptive systems on various opiate, adrenergic, glutamate, purine and other receptors located on neurons posterior horn. This pain impulse is then transmitted to the overlying parts of the central nervous system (thalamus, cerebral cortex), where information about the nature and location of pain is processed and interpreted.

However, the resulting pain perception is largely dependent on the activity of the ANS. The brain's ANS plays a key role in the formation of pain and changes in the response to pain. Their wide representation in the brain and inclusion in various neurotransmitter mechanisms (norepinephrine, serotonin, opioids, dopamine) are obvious. The ANS does not work in isolation, but by interacting with each other and with other systems, they regulate not only pain sensitivity, but also autonomic, motor, neuroendocrine, emotional and behavioral manifestations of pain associated with pain. This circumstance allows us to consider them as the most important system that determines not only the characteristics of pain, but also its diverse psychophysiological and behavioral correlates. Depending on the activity of the ANS, pain may increase or decrease.

Pain Treatment Medicines

Pain medications are prescribed based on the expected mechanisms of pain. Understanding the mechanisms of pain syndrome formation allows for individual selection of treatment. For nociceptive pain, non-steroidal anti-inflammatory drugs (NSAIDs) and opioid analgesics have proven themselves to be the best. For neuropathic pain, the use of antidepressants, anticonvulsants, local anesthetics, and blockers is justified. potassium channels.

Nonsteroidal anti-inflammatory drugs

If inflammatory mechanisms play a leading role in the pathogenesis of pain, then the use of NSAIDs is most appropriate in this case. Their use makes it possible to suppress the synthesis of algogens in damaged tissues, which prevents the development of peripheral and central sensitization. In addition to the analgesic effect, drugs from the NSAID group have anti-inflammatory and antipyretic effects.

The modern classification of NSAIDs involves the division of these drugs into several groups, differing in selectivity for cyclooxygenase enzymes type 1 and 2, which are involved in a number of physiological and pathological processes (Fig. 12).

It is believed that the analgesic effect of drugs from the NSAID group is mainly associated with their effect on COX2, and gastrointestinal complications are due to their effect on COX1. However, research in recent years has also revealed other mechanisms of the analgesic action of some drugs from the NSAID group. Thus, it has been shown that diclofenac (Voltaren) can have an analgesic effect not only through COX-dependent, but also other peripheral, as well as central mechanisms.

Local anesthetics

Limiting the flow of nociceptive information into the central nervous system can be achieved by using various local anesthetics, which can not only prevent the sensitization of nociceptive neurons, but also help normalize microcirculation in the damaged area, reduce inflammation and improve metabolism. Along with this, local anesthetics relax striated muscles and eliminate pathological muscle tension, which is an additional source of pain.
Local anesthetics include substances that cause temporary loss of tissue sensitivity as a result of blocking the conduction of impulses in nerve fibers. The most common among them are lidocaine, novocaine, articaine and bupivacaine. The mechanism of action of local anesthetics is associated with blocking Na + channels on the membrane of nerve fibers and inhibition of the generation of action potentials.

Anticonvulsants

Long-term irritation of nociceptors or peripheral nerves leads to the development of peripheral and central sensitization (hyperexcitability).

Current anticonvulsants used to treat pain have various points applications. Diphenine, carbamazepine, oxcarbazepine, lamotrigine, valproate, and topiromate act primarily by inhibiting the activity of voltage-gated sodium channels, preventing the spontaneous generation of ectopic discharges in the damaged nerve. The effectiveness of these drugs has been proven in patients with trigeminal neuralgia, diabetic neuropathy, and phantom pain syndrome.

Gabapentin and pregabalin inhibit the entry of calcium ions into the presynaptic terminal of nociceptors, thereby reducing the release of glutamate, which leads to a decrease in the excitability of nociceptive neurons of the spinal cord (reduces central sensitization). These drugs also modulate the activity of NMDA receptors and reduce the activity of Na + channels.

Antidepressants

Antidepressants and drugs from the opioid group are prescribed to enhance antinociceptive effects. In the treatment of pain syndromes, drugs are mainly used whose mechanism of action is associated with the blockade of the reuptake of monoamines (serotonin and norepinephrine) in the central nervous system. The analgesic effect of antidepressants may be partly due to an indirect analgesic effect, since improved mood has a beneficial effect on pain assessment and reduces pain perception. In addition, antidepressants potentiate the effect of narcotic analgesics by increasing their affinity for opioid receptors.

Muscle relaxants

Muscle relaxants are used in cases where muscle spasm contributes to pain. It should be noted that muscle relaxants act at the level of the spinal cord and not at the muscle level.
In our country, tizanidine, baclofen, mydocalm, as well as drugs from the benzodiazepine group (diazepam) are used to treat painful muscle spasms. Recently, injections of botulinum toxin type A have been used to relax muscles in the treatment of myofascial pain syndromes. For the presented drugs - different points applications. Baclofen is a GABA receptor agonist and inhibits the activity of interneurons at the spinal level.
Tolperisone blocks Na + and Ca 2+ channels of spinal cord interneurons and reduces the release of pain mediators in spinal cord neurons. Tizanidine is a muscle relaxant central action. The main point of application of its action is in the spinal cord. By stimulating presynaptic a2 receptors, it inhibits the release of excitatory amino acids that stimulate N-methyl-D-aspartate receptors (NMDA receptors). As a result, polysynaptic transmission of excitation is suppressed at the level of interneurons of the spinal cord. Since it is this mechanism that is responsible for excess muscle tone, then when it is suppressed, muscle tone decreases. In addition to muscle relaxant properties, tizanidine also has a moderate central analgesic effect.
Tizanidine was originally developed for the treatment of muscle spasms in various neurological diseases (with traumatic injuries brain and spinal cord, multiple sclerosis, stroke). However, soon after the start of its use, the analgesic properties of tizanidine were revealed. Currently, the use of tizanidine in monotherapy and in the complex treatment of pain syndromes has become widespread.

Selective Neuronal Potassium Channel Activators (SNEPCO)

A fundamentally new class of drugs for the treatment of pain syndromes are selective activators of neuronal potassium channels - SNEPCO (Selective Neuronal Potassium Channel Opener), which affect the processes of sensitization of dorsal horn neurons by stabilizing the resting membrane potential.

The first representative of this class medicines- flupirtine (Katadolon), which has wide range valuable pharmacological properties that distinguish it favorably from other painkillers.

Subsequent chapters provide detailed information about pharmacological properties and the mechanism of action of Katadolon, presents the results of studies of its effectiveness and safety, describes the experience of using the drug in different countries world, recommendations are given for the use of Katadolon for various pain syndromes.

Pain. Everyone knows what this feeling is. Despite the fact that it is very unpleasant, its function is useful. After all, severe pain is a signal from the body, which is aimed at drawing a person’s attention to problems in the body. If your relationship with him is in order, then you can easily distinguish the pain that occurs after exercise from that that appears after a very spicy dish.

Most often it is divided into two types: primary and secondary. Other names are epicritic and protopathic.

Primary pain

Primary is pain that is caused directly by any damage. It could be sharp pain after a needle prick. This type is very sharp and strong, but after the impact of the damaging object stops, the primary pain immediately disappears.

It often happens that pain after the disappearance of the traumatic effect does not disappear, but acquires the status of a chronic disease. Sometimes it can persist for so long that even doctors are unable to determine the reason why it originally occurred.

Secondary pain

Secondary pain is already nagging in nature. At the same time, it is very difficult to indicate the place in which it is localized. In such a situation, it is customary to talk about a pain syndrome that requires treatment.

Why does pain occur?

So, a person has secondary pain. What is this syndrome? What are its reasons? After tissue damage occurs, pain receptors send a corresponding signal to the central nervous system, that is, the brain and spinal cord. This process associated with electrical impulses and the release of special substances that are responsible for the transmission of nerve signals between neurons. Since the human nervous system is quite a complex system, which has many connections, in the management of sensations associated with pain, there are often failures in which neurons send pain impulses even when there are no stimuli.

Localization of pain

Based on localization, the syndrome is divided into two forms: local and projection. If the failure occurred somewhere on the periphery of the human nervous system, then the pain syndrome almost exactly coincides with the damaged area. This may include pain after visiting the dentist.

If a malfunction occurs in the central nervous system, then a projection form appears. This includes phantom, wandering pain.

Depth of pain

According to this characteristic, visceral and somatic are divided.

Visceral pain refers to sensations from the internal organs.

Somatic pain sensations are perceived as joint, muscle and skin pain.

There are symptoms that require urgent attention.

Very strong, sharp pain in the head that has never been experienced before

In this case, you must immediately consult a doctor. This can be either pain from a cold or a cerebral hemorrhage, which is much more serious. If there is no certainty about the reason that caused such a feeling, then you need to go through medical check or call ambulance. Treating acute pain before its cause is identified is not the most a good option. The main sign is that the sensation goes away before the damage heals. Correct diagnosis is very important.

Pain in the throat, chest, jaw, arm, shoulder, or stomach

If you experience chest pain, this may not be a good sign of pneumonia or a heart attack. But you need to know that with heart disease there is usually some discomfort, not pain. What is discomfort in such diseases? Some people complain of tightness in the chest, as if someone is sitting on top of them.

The discomfort associated with heart disease may be felt in the upper chest, but also in the jaw or throat, left arm or shoulder, and abdominal cavity. All this may be accompanied by nausea. So, if a person constantly experiences something like this and knows that he belongs to a risk group, he needs to be checked urgently. After all, very often people waste time because they misinterpret the symptoms of pain. Doctors say that discomfort that occurs from time to time should also be taken seriously. It may be associated with physical stress, emotional disorder or excitement. If this is experienced after working in the garden, and then goes away during rest, then this is most likely angina pectoris, attacks of which most often occur in hot or cold weather. Discomfort and pain in women with cardiovascular diseases are subtle. They can masquerade as symptoms of gastrointestinal diseases, which include abdominal discomfort and bloating. After menopause, the risk of such diseases increases sharply. Therefore, you need to be attentive to your health.

Pain in the lower back or between the shoulder blades

Some doctors say this is a sign of arthritis. But there are other options to keep in mind. This could be a gastrointestinal disease or heart attack. In a particular case, aching pain in these places may be a symptom. In people who are at risk for diseases associated with the heart and blood vessels, the integrity of the organs may be compromised. These people include those with excessively high arterial pressure, circulatory problems, as well as smokers and diabetics.

Severe abdominal pain

This may include inflammation of the appendix, problems with the pancreas and gall bladder, as well as stomach ulcers and other disorders that cause abdominal pain. You need to see a doctor.

Pain in the calf muscles

Thrombosis is a very serious disease. It causes severe pain. What is thrombosis? This is when a blood clot forms in the veins, causing discomfort. A large number of people face this disease. Its danger lies in the fact that part of such a clot breaks off, which leads to death. Risk factors are elderly age, cancer, low mobility after prolonged bed rest, obesity, pregnancy. Sometimes there is no pain, but only swelling. In any case, it is better to seek help immediately.

Heat in the legs

This problem is familiar to many people with diabetes. It was from this that this dangerous disease. Some people don't know they have diabetes. So heat in the legs is one of the first signs. There is a tingling sensation or sensation that may indicate damaged nerves.

Scattered pain, as well as combined

A variety of physical, painful symptoms often occur with depressive states. Patients may complain of soreness in the limbs or abdomen, diffuse pain in the head, and sometimes all three. Due to the fact that unpleasant sensations can be chronic and not felt strongly, patients and their families can simply ignore such symptoms. And the stronger depressive disorder, those more difficult for a person describe the sensations. Pain after psychological trauma is often difficult to explain. This may confuse doctors. This is why it is important to identify other symptoms before making a diagnosis of depression. If you have lost interest in life, you cannot think and work with high efficiency, and you have quarrels with people, you need to get help from a doctor. When something hurts, you don’t have to endure it in silence. After all, depression is not just a deterioration in the condition and quality of life. It must be treated very actively before it has time to cause serious changes.

All of the above types of pain are dangerous, as they can be symptoms serious illnesses. Therefore, at the slightest sign you should immediately seek help from a doctor. After all, the essence of pain is for a person to understand that something is wrong in the body. Except discomfort and significant changes in the human body, pain can lead to sad consequences, the worst of which is death.

Among all sensory processes The greatest suffering comes from the sensation of pain.

Pain is a mental state that occurs as a result of super-strong or destructive effects on the body when its existence or integrity is threatened.

The clinical significance of pain as a symptom of a violation of the normal course of physiological processes is important, since a number of pathological processes of the human body make themselves felt in pain even before the appearance of external symptoms diseases. It should be noted that adaptation to pain practically does not occur.

From the point of view of emotional experience, the sensation of pain has an oppressive and painful character, sometimes the nature of suffering, and serves as a stimulus for a variety of defensive reactions aimed at eliminating the external or internal stimuli that caused the occurrence of this sensation.

Painful sensations are formed in the central nervous system as a result of the combination of processes that begin in receptor formations embedded in the skin or internal organs, impulses from which through special pathways enter the subcortical systems of the brain, which enter into dynamic interaction with the processes of the cerebral cortex.

Cortical as well as subcortical formations are involved in the formation of pain. Pain occurs as a result of direct impact on the body external stimuli, and with changes in the body itself caused by various pathological processes. Pain can arise or intensify through a conditioned reflex mechanism and be psychogenically caused.

The pain reaction is the most inert and strong unconditioned reaction. The sensation of pain is, to a certain extent, susceptible to influence from higher mental processes associated with the activity of the cortex and depending on such personal characteristics as direction, conviction, value orientations, etc. Numerous examples testify to both courage, the ability, when experiencing pain, not to succumb to it, but to act, obeying highly moral motives, and to cowardice , focusing on your pain sensations.

The sensation of pain usually appears with the onset of the disease, activation or progression pathological process. The patient's attitude towards acute and chronic pain is different.

For example. In case of acute toothache, a person’s entire attention is focused on the object of pain, he looks for ways to get rid of pain by any means (reception various drugs, surgery, any procedures just to relieve pain). Paroxysmal pain in chronic diseases is especially difficult to experience; the reaction to them often intensifies over time. Patients expect them with fear; a feeling of hopelessness, futility, and despair appears. The pain in such cases can be so excruciating that a person waits for death as relief from torment.

With chronic pain, there may also be some adaptation to the sensations of pain and to the experiences associated with it.

Some doctors distinguish between so-called organic and psychogenic pain. The contrast between pain is not sufficiently substantiated, since all doctors are well aware that in a psychogenic situation, as a rule, there is an increase in pain that is of an organic nature.

The signal meaning of pain is a warning of impending danger.

Severe pain can completely take over a person’s thoughts and feelings and focus all his attention on itself. It can lead to sleep disturbances and various neurotic reactions.

Sick, suffering severe pain, need attentive and caring attitude to their complaints and requests. Pain debilitates the patient more than any other disorder.

All people have felt pain at one time or another. The pain can range from mild to severe, appear once, be constant, or come and go periodically. There are many types of pain, and often pain is the first sign that something is wrong with the body.

Most often, doctors are consulted when acute pain or chronic pain occurs.

What is acute pain?

Acute pain begins suddenly and is usually described as sharp. It often serves as a warning about illness or possible threat for the body from the outside external factors. Acute pain can be caused by many factors, such as:

• Medical procedures and surgical intervention(without anesthesia);
• Bone fractures;
• Dental treatment;
• Burns and cuts;
• Childbirth in women;

Acute pain can be moderate and last literally seconds. But there is also severe acute pain that does not go away for weeks or even months. In most cases, acute pain is treated for no longer than six months. Typically, acute pain disappears when its main cause is eliminated - wounds are treated and injuries heal. But sometimes constant acute pain develops into chronic pain.

What is chronic pain?

Chronic pain is pain that lasts longer than three months. It even happens that the wounds that caused the pain have already healed or other provoking factors have been eliminated, but the pain still does not disappear. Pain signals can remain active in the nervous system for weeks, months, or even years. As a result, a person may experience pain-related physical and emotional states that interfere with normal life. The physical effects of pain are muscle tension, low mobility And physical activity, loss of appetite. At the emotional level, depression, anger, anxiety, and fear of re-injury appear.

Common types of chronic pain are:

• Headache;
• Abdominal pain;
• Back pain and in particular lower back pain;
• Pain in the side;
• Cancer pain;
• Arthritis pain;
• Neurogenic pain due to nerve damage;
• Psychogenic pain (pain that is not associated with past diseases, injuries or any internal problems).

Chronic pain can begin after an injury or infection and for other reasons. But for some people, chronic pain is not associated with any injury or damage at all, and it is not always possible to explain why such chronic pain appears.

Our clinic has specialized specialists on this issue.

(9 specialists)

2. Doctors who treat pain

Depending on what and how it hurts, and what causes the pain, pain can be diagnosed and treated various specialists– neurologists, neurosurgeons, orthopedic surgeons, oncologists, therapists and other doctors of specialized specialties who will treat the cause of pain - a disease, one of the symptoms of which is pain.

3. Diagnosis of pain

There are various methods to help determine the cause of pain. In addition to a general analysis of pain symptoms, special tests and studies may be performed:

• Computed tomography (CT);
• Magnetic resonance imaging (MRI);
• Discography (examination to diagnose back pain with the introduction contrast agent into the vertebral disc);
• Myelogram (also done with the injection of a contrast agent into the spinal canal to enhance X-ray imaging. The myelogram helps to see nerve compression caused by herniated discs or fractures);
• Bone scan to help identify abnormalities bone tissue due to infection, injury or other reasons;
• Ultrasound of internal organs.

4. Pain treatment

Depending on the severity of the pain and its causes, pain treatment may vary. Of course, you should not self-medicate, especially if the pain is severe or does not go away for a long time. Symptomatic treatment pain may include:

• Over-the-counter pain relievers, including muscle relaxants, antispasmodics, and some antidepressants;
• Nerve block (blocking a group of nerves with an injection of local anesthetic);
• Alternative Methods pain treatments such as acupuncture, hirudotherapy, apitherapy and others;
• Electrical stimulation;
• Physiotherapy;
• Surgery pain;
• Psychological help.

Some pain medications work better when they are combined with other pain treatments.