What is responsible for pain in the human body. Pain: causes and methods of treatment
Pain is an important adaptive reaction of the body, which serves as an alarm signal.
However, when pain becomes chronic, it loses its physiological significance and can be considered a pathology.
Pain is an integrative function of the body, mobilizing various functional systems to protect against the effects of a damaging factor. It manifests itself as vegetosomatic reactions and is characterized by certain psycho-emotional changes.
The term "pain" has several definitions:
- this is a unique psychophysiological state that occurs as a result of exposure to super-strong or destructive stimuli that cause organic or functional disorders in the body;
- in a narrower sense, pain (dolor) is a subjective painful sensation that arises as a result of exposure to these super-strong stimuli;
- pain is a physiological phenomenon that informs us about harmful effects that damage or pose a potential danger to the body.
Thus, pain is both a warning and a protective reaction.
The International Association for the Study of Pain gives the following definition of pain (Merskey, Bogduk, 1994):
Pain is an unpleasant sensation and emotional experience associated with actual and potential tissue damage or a condition described in terms of such damage.
The phenomenon of pain is not limited exclusively to organic or functional disorders where it is located, pain also affects the functioning of the body as an individual. Over the years, researchers have described an untold number of adverse physiological and psychological consequences no pain relief.
The physiological consequences of untreated pain of any location can include everything from decreased function gastrointestinal tract And respiratory system and ending with increased metabolic processes, increased growth of tumors and metastases, decreased immunity and prolongation of healing time, insomnia, increased blood clotting, loss of appetite and decreased ability to work.
The psychological consequences of pain can manifest themselves in the form of anger, irritability, feelings of fear and anxiety, resentment, discouragement, despondency, depression, solitude, loss of interest in life, decreased ability to fulfill family responsibilities, decreased sexual activity, which leads to family conflicts and even requests for euthanasia.
Psychological and emotional effects often influence the patient's subjective response, exaggerating or downplaying the significance of pain.
In addition, the degree of self-control of pain and illness by the patient, the degree of psychosocial isolation, the quality of social support and, finally, the patient’s knowledge of the causes of pain and its consequences may play a certain role in the severity of the psychological consequences of pain.
The doctor almost always has to deal with developed manifestations of pain—emotions and pain behavior. This means that the effectiveness of diagnosis and treatment is determined not only by the ability to identify etiopathogenetic mechanisms somatic condition manifested or accompanied by pain, but also the ability to see the problems of limitation behind these manifestations usual life patient.
Studying the causes and pathogenesis of pain and pain syndromes dedicated significant amount works, including monographs.
Pain has been studied as a scientific phenomenon for over a hundred years.
There are physiological and pathological pain.
Physiological pain occurs at the moment of perception of sensations by pain receptors, it is characterized by a short duration and is directly dependent on the strength and duration of the damaging factor. The behavioral reaction in this case interrupts the connection with the source of damage.
Pathological pain can occur in both receptors and nerve fibers; it is associated with prolonged healing and is more destructive due to the potential threat of disruption of normal psychological and social existence individual; behavioral reaction in this case is the appearance of anxiety, depression, depression, which aggravates somatic pathology. Examples of pathological pain: pain at the site of inflammation, neuropathic pain, deafferentation pain, central pain.
Each type of pathological pain has clinical features, which make it possible to recognize its causes, mechanisms and localization.
Types of pain
There are two types of pain.First type - sharp pain, caused by tissue damage that decreases as it heals. Acute pain has a sudden onset, short duration, clear localization, appears when exposed to intense mechanical, thermal or chemical factor. It can be caused by infection, injury or surgery, lasts for hours or days and is often accompanied by symptoms such as rapid heartbeat, sweating, paleness and insomnia.
Acute pain (or nociceptive) is pain that is associated with the activation of nociceptors after tissue damage, corresponds to the degree of tissue damage and the duration of action of the damaging factors, and then completely regresses after healing.
Second type- chronic pain develops as a result of damage or inflammation of tissue or nerve fiber, it persists or recurs for months or even years after healing, does not have a protective function and causes suffering to the patient, it is not accompanied by signs characteristic of acute pain.
Unbearable chronic pain has a negative impact on a person's psychological, social and spiritual life.
With continuous stimulation of pain receptors, their sensitivity threshold decreases over time, and non-painful impulses also begin to cause pain. Researchers associate the development of chronic pain with untreated acute pain, emphasizing the need for adequate treatment.
Untreated pain subsequently leads not only to a financial burden on the patient and his family, but also entails huge costs for society and the healthcare system, including longer hospitalization periods, decreased ability to work, multiple visits to outpatient clinics (polyclinics) and points of care. emergency care. Chronic pain is the most common common cause of long-term partial or total disability.
There are several classifications of pain, one of them, see table. 1.
Table 1. Pathophysiological classification chronic pain
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1. Arthropathy ( rheumatoid arthritis, osteoarthritis, gout, post-traumatic arthropathy, mechanical cervical and spinal syndromes) 1. Postherpetic neuralgia Mixed or indeterminate pathophysiology 1. Chronic recurring headaches (with increased blood pressure, migraine, mixed headaches) |
Classification of pain
A pathogenetic classification of pain has been proposed (Limansky, 1986), where it is divided into somatic, visceral, neuropathic and mixed.Somatic pain occurs when the skin of the body is damaged or stimulated, as well as when deeper structures are damaged - muscles, joints and bones. Bone metastases and surgical interventions are ordinary reasons somatic pain in patients suffering from tumors. Somatic pain is usually constant and quite clearly limited; it is described as throbbing pain, gnawing pain, etc.
Visceral pain
Visceral pain is caused by stretching, compression, inflammation or other irritation of internal organs.It is described as deep, compressive, generalized and may radiate into the skin. Visceral pain is usually constant, and it is difficult for the patient to establish its localization. Neuropathic (or deafferentation) pain occurs when nerves are damaged or irritated.
It may be constant or intermittent, sometimes shooting, and is usually described as sharp, stabbing, cutting, burning or an unpleasant sensation. In general, neuropathic pain is the most severe and difficult to treat compared to other types of pain.
Clinically pain
Clinically, pain can be classified in the following way: nocigenic, neurogenic, psychogenic.This classification may be useful for initial therapy, however, in the future, such a division is impossible due to the close combination of these pains.
Nocigenic pain
Nocigenic pain occurs when skin nociceptors, deep tissue nociceptors, or internal organs are irritated. The impulses that appear in this case follow the classical anatomical pathways, reaching the highest departments nervous system, are reflected by consciousness and form the sensation of pain.Pain when internal organs are damaged is a consequence fast contraction, spasm or stretching of smooth muscles, since smooth muscles themselves are insensitive to heat, cold or cut.
Pain from internal organs having sympathetic innervation, can be felt in certain areas on the surface of the body (Zakharyin-Ged zones) - this is referred pain. The most famous examples of such pain are pain in the right shoulder and right side neck with gallbladder damage, pain in the lower back with disease Bladder and, finally, pain in the left arm and left half of the chest due to heart disease. The neuroanatomical basis of this phenomenon is not entirely understood.
A possible explanation is that the segmental innervation of internal organs is the same as that of distant areas of the body surface, but this does not explain the reason for the reflection of pain from the organ to the body surface.
Nocigenic pain is therapeutically sensitive to morphine and other narcotic analgesics.
Neurogenic pain
This type of pain can be defined as pain due to damage to the peripheral or central nervous system and is not explained by irritation of nociceptors.Neurogenic pain has many clinical forms.
These include some lesions of the peripheral nervous system, such as postherpetic neuralgia, diabetic neuropathy, incomplete damage to the peripheral nerve, especially the median and ulnar nerve (reflex sympathetic dystrophy), and separation of the branches of the brachial plexus.
Neurogenic pain due to damage to the central nervous system is usually due to cerebrovascular accident - this is known under the classical name of "thalamic syndrome", although studies (Bowsher et al., 1984) show that in most cases the lesions are located in areas other than the thalamus.
Many pains are mixed and clinically manifest as nocigenic and neurogenic elements. For example, tumors cause both tissue damage and nerve compression; in diabetes, nocigenic pain occurs due to damage peripheral vessels, and neurogenic - due to neuropathy; for hernias intervertebral disc, compressing nerve root, the pain syndrome includes a burning and shooting neurogenic element.
Psychogenic pain
The statement that pain can be exclusively psychogenic in origin is debatable. It is widely known that the patient's personality shapes the pain experience.It is strengthened by hysterical personalities, and more accurately reflects the reality in non-hysterical patients. It is known that people of different ethnic groups differ in their perception of postoperative pain.
Patients of European descent report less intense pain than American blacks or Hispanics. They also have lower pain intensity compared to Asians, although these differences are not very significant (Faucett et al., 1994). Some people are more resistant to developing neurogenic pain. Since this tendency has the aforementioned ethnic and cultural characteristics, it appears to be innate. Therefore, the prospects for research aimed at finding the localization and isolation of the “pain gene” are so tempting (Rappaport, 1996).
Any chronic disease or illness accompanied by pain affects the emotions and behavior of the individual.
Pain often leads to anxiety and tension, which themselves increase the perception of pain. This explains the importance of psychotherapy in pain control. Biological Feedback, relaxation training, behavioral therapy and hypnosis, used as psychological interventions, have been found to be useful in some stubborn, treatment-refractory cases (Bonica, 1990, Wall and Melzack, 1994, Hart and Alden, 1994).
Treatment is effective if it takes into account psychological and other systems ( environment, psychophysiology, behavioral response), which potentially influence pain perception(Cameron, 1982).
The discussion of the psychological factor of chronic pain is based on the theory of psychoanalysis, from behavioral, cognitive and psychophysiological positions (Gamsa, 1994).
G.I. Lysenko, V.I. Tkachenko
This is the first of the symptoms described by doctors of ancient Greece and Rome - signs of inflammatory damage. Pain is something that signals us about some trouble occurring inside the body or about the action of some destructive and irritating factor from the outside.
Pain, according to the well-known Russian physiologist P. Anokhin, is designed to mobilize various functional systems of the body to protect it from the effects of harmful factors. Pain includes such components as: sensation, somatic (bodily), autonomic and behavioral reactions, consciousness, memory, emotions and motivation. Thus, pain is a unifying integrative function of an integral living organism. In this case, the human body. For living organisms, even without possessing signs of higher nervous activity may experience pain.
There are facts of changes in electrical potentials in plants, which were recorded when their parts were damaged, as well as the same electrical reactions when researchers caused injury to neighboring plants. Thus, the plants responded to damage caused to them or neighboring plants. Only pain has such a unique equivalent. This is something interesting, one might say, universal property all biological organisms.
Types of pain – physiological (acute) and pathological (chronic).
Pain happens physiological (acute) And pathological (chronic).Acute pain
According to the figurative expression of academician I.P. Pavlova, is the most important evolutionary acquisition, and is required for protection from the effects of destructive factors. The meaning of physiological pain is to throw away everything that threatens life process, disrupts the body’s balance with the internal and external environment.Chronic pain
This phenomenon is somewhat more complex, which is formed as a result of long-term pathological processes in the body. These processes can be either congenital or acquired during life. Acquired pathological processes include the following: long-term existence of foci of inflammation with various causes, various neoplasms (benign and malignant), traumatic injuries, surgical interventions, outcomes inflammatory processes(for example, the formation of adhesions between organs, changes in the properties of the tissues that make up them). Congenital pathological processes include the following - various anomalies in the location of internal organs (for example, the location of the heart outside the chest), congenital anomalies development (for example, congenital intestinal diverticulum and others). Thus, a long-term source of damage leads to constant and minor damage to the structures of the body, which also constantly creates pain impulses about damage to these structures of the body affected by the chronic pathological process.Since these injuries are minimal, the pain impulses are quite weak, and the pain becomes constant, chronic and accompanies a person everywhere and almost around the clock. The pain becomes habitual, but does not disappear anywhere and remains a source of long-term irritation. Pain syndrome that exists in a person for six or more months leads to significant changes in the human body. There is a violation of the leading regulatory mechanisms essential functions human body, disorganization of behavior and psyche. The social, family and personal adaptation of this particular individual suffers.
How common is chronic pain?
According to research World Organization Health (WHO), every fifth person on the planet suffers from chronic pain caused by all kinds of pathological conditions associated with diseases various organs and body systems. This means that at least 20% of people suffer from chronic pain varying degrees expressiveness, varying intensity and duration.
What is pain and how does it occur? The part of the nervous system responsible for transmitting pain sensitivity, substances that cause and maintain pain.
The sensation of pain is a complex physiological process, including peripheral and central mechanisms, and having emotional, mental, and often vegetative overtones. The mechanisms of the pain phenomenon have not been fully disclosed to date, despite numerous scientific studies that continue to this day. However, let us consider the main stages and mechanisms of pain perception.Nerve cells that transmit pain signals, types of nerve fibers.
The very first stage of pain perception is the effect on pain receptors ( nociceptors). These pain receptors are located in all internal organs, bones, ligaments, in the skin, on the mucous membranes of various organs in contact with the external environment (for example, on the mucous membrane of the intestines, nose, throat, etc.). Today, there are two main types of pain receptors: the first are free nerve endings, when irritated, a feeling of dull, diffuse pain occurs, and the second are complex pain receptors, when excited, a feeling of acute and localized pain occurs. That is, the nature of pain directly depends on which pain receptors perceived the irritating effect. Regarding specific agents that can irritate pain receptors, we can say that they include various biologically active substances (BAS), formed in pathological foci (the so-called algogenic substances). These substances include various chemical compounds - these are biogenic amines, and products of inflammation and cell breakdown, and products of local immune reactions. All these substances, completely different in chemical structure, can have an irritating effect on pain receptors of various locations.
Prostaglandins are substances that support the body's inflammatory response.
However, there are a number of chemical compounds involved in biochemical reactions that themselves cannot directly affect pain receptors, but enhance the effects of substances that cause inflammation. This class of substances, for example, includes prostaglandins. Prostaglandins are formed from special substances - phospholipids, which form the basis cell membrane. This process proceeds as follows: a certain pathological agent (for example, enzymes form prostaglandins and leukotrienes. Prostaglandins and leukotrienes are generally called eicosanoids and play an important role in the development of the inflammatory response. The role of prostaglandins in the formation of pain in endometriosis, premenstrual syndrome, and painful menstrual syndrome (algomenorrhea) has been proven.So, we have considered the first stage of formation pain– influence on special pain receptors. Let's consider what happens next, how a person feels pain of a certain localization and nature. To understand this process, it is necessary to become familiar with the pathways.
How does the pain signal enter the brain? Pain receptor, peripheral nerve, spinal cord, thalamus - more about them.
Bioelectric pain signal formed in the pain receptor along several types of nerve conductors (peripheral nerves), bypassing intraorgan and intracavity ganglia, heading towards spinal nerve ganglia (nodes) located next to the spinal cord. These nerve ganglia accompany every vertebra from the cervical to some lumbar. Thus, a chain of nerve ganglia is formed, running to the right and left along the spinal column. Each nerve ganglion is connected to the corresponding part (segment) of the spinal cord. The further path of the pain impulse from the spinal nerve ganglia is sent to the spinal cord, which is directly connected to the nerve fibers. 
In fact, the spinal could is heterogeneous structure– it contains white and gray matter (as in the brain). If the spinal cord is examined in a cross section, the gray matter will look like the wings of a butterfly, and the white matter will surround it on all sides, forming the rounded outlines of the boundaries of the spinal cord. So, rear end These butterfly wings are called the dorsal horns of the spinal cord. They carry nerve impulses to the brain. The front horns, logically, should be located in front of the wings - and this is what happens. It is the anterior horns that conduct nerve impulses from the brain to the peripheral nerves. Also in the spinal cord in its central part there are structures that directly connect nerve cells anterior and posterior horns of the spinal cord - thanks to this, it is possible to form the so-called “short reflex arc”, when some movements occur unconsciously - that is, without the participation of the brain. An example of how a short reflex arc works is when a hand is pulled away from a hot object.
Since the spinal cord has a segmental structure, therefore, each segment of the spinal cord includes nerve conductors from its own area of responsibility. In the presence of an acute stimulus from the cells of the posterior horns of the spinal cord, excitation can abruptly switch to the cells of the anterior horns of the spinal segment, which causes a lightning-fast motor reaction. If you touched a hot object with your hand, you immediately pulled your hand back. At the same time, the pain impulse still reaches the cerebral cortex, and we realize that we have touched a hot object, although our hand has already been reflexively withdrawn. Similar neuro-reflex arcs for individual segments of the spinal cord and sensitive peripheral areas may differ in the construction of levels of participation of the central nervous system.
How does a nerve impulse reach the brain?
Further from the posterior horns of the spinal cord the path pain sensitivity is sent to the overlying parts of the central nervous system along two pathways - along the so-called “old” and “new” spinothalamic (nerve impulse path: spinal cord - thalamus) pathways. The names “old” and “new” are conditional and speak only about the time of appearance of these paths in the historical period of the evolution of the nervous system. We will not, however, go into the intermediate stages of a rather complex neural pathway, we will limit ourselves only to stating the fact that both of these paths of pain sensitivity end in areas of the sensitive cerebral cortex. Both the “old” and “new” spinothalamic pathways pass through the thalamus (a special part of the brain), and the “old” spinothalamic pathway also passes through a complex of structures of the limbic system of the brain. The structures of the limbic system of the brain are largely involved in the formation of emotions and the formation of behavioral reactions. It is assumed that the first, evolutionarily younger system (the “new” spinothalamic pathway) for conducting pain sensitivity creates a more specific and localized pain, while the second, evolutionarily more ancient (the “old” spinothalamic pathway) serves to conduct impulses that give the sensation of viscous, poorly localized pain. pain. In addition to this, this “old” spinothalamic system provides emotional coloring of the pain sensation, and also participates in the formation of behavioral and motivational components of emotional experiences associated with pain.
Before reaching sensitive areas of the cerebral cortex, pain impulses undergo so-called pre-processing in certain parts of the central nervous system. This is the already mentioned thalamus (visual thalamus), hypothalamus, reticular (reticular) formation, areas of the middle and medulla oblongata. The first, and perhaps one of the most important filters on the path of pain sensitivity is the thalamus. All the sensations from external environment, from the receptors of internal organs - everything passes through the thalamus. An unimaginable amount of sensitive and painful impulses passes through this part of the brain every second, day and night. We do not feel the friction of the heart valves, the movement of the abdominal organs, and all kinds of articular surfaces against each other - and all this is thanks to the thalamus.
If the work of the so-called anti-pain system is disrupted (for example, in the absence of the production of internal, own morphine-like substances, which arose due to the use of narcotic drugs), the above-mentioned barrage of all kinds of pain and other sensitivity simply overwhelms the brain, leading to terrifying in duration, strength and severity emotional and painful sensations. This is the reason, in a somewhat simplified form, for the so-called “withdrawal” when there is a deficiency in the supply of morphine-like substances from the outside against the background long-term use narcotic drugs.
How is the pain impulse processed by the brain?
The posterior nuclei of the thalamus provide information about the localization of the source of pain, and its median nuclei provide information about the duration of exposure to the irritating agent. The hypothalamus, as the most important regulatory center of the autonomic nervous system, participates in the formation of the autonomic component of the pain reaction indirectly, through the involvement of centers regulating metabolism, the functioning of the respiratory, cardiovascular and other body systems. The reticular formation coordinates already partially processed information. The role of the reticular formation in the formation of the sensation of pain as a kind of special integrated state of the body, with the inclusion of all kinds of biochemical, vegetative, and somatic components, is especially emphasized. The limbic system of the brain provides negative emotional coloring. The very process of awareness of pain as such, determining the localization of the pain source (meaning a specific area own body) in combination with the most complex and varied reactions to pain impulses necessarily occurs with the participation of the cerebral cortex. The sensory areas of the cerebral cortex are the highest modulators of pain sensitivity and play the role of the so-called cortical analyzer of information about the fact, duration and localization of the pain impulse. It is at the level of the cortex that integration of information from various types conductors of pain sensitivity, which means the full development of pain as a multifaceted and diverse sensation. At the end of the last century, it was revealed that each level of the pain system, from the receptor apparatus to the central analyzing systems of the brain, can have the property of increasing pain impulses. Like a kind of transformer substations on power lines.
We even have to talk about the so-called generators of pathologically enhanced excitation. Thus, from a modern point of view, these generators are considered as the pathophysiological basis of pain syndromes. The mentioned theory of systemic generator mechanisms allows us to explain why, with minor irritation, the pain response can be quite significant in sensation, why, after the cessation of the stimulus, the sensation of pain continues to persist, and also helps to explain the appearance of pain in response to stimulation of cutaneous projection zones ( reflexogenic zones) for pathology of various internal organs.
Chronic pain of any origin leads to increased irritability, decreased performance, loss of interest in life, sleep disturbances, changes in the emotional-volitional sphere, and often leads to the development of hypochondria and depression. All of these consequences themselves intensify the pathological pain reaction. The occurrence of such a situation is interpreted as the formation of closed vicious circles: painful stimulus – psycho-emotional disorders – behavioral and motivational disorders, manifested in the form of social, family and personal maladjustment – pain.
Anti-pain system (antinociceptive) - role in the human body. Pain threshold
Along with the existence of a pain system in the human body ( nociceptive), there is also an anti-pain system ( antinociceptive). What does the anti-pain system do? First of all, each organism has its own genetically programmed threshold for the perception of pain sensitivity. This threshold helps explain why different people react differently to stimuli of the same strength, duration and nature. The concept of sensitivity threshold is a universal property of all receptor systems of the body, including pain. Just like the pain sensitivity system, the anti-pain system has a complex multi-level structure, starting from the level of the spinal cord and ending with the cerebral cortex. How is the activity of the anti-pain system regulated?
The complex activity of the anti-pain system is ensured by a chain of complex neurochemical and neurophysiological mechanisms. The main role in this system belongs to several classes of chemical substances - brain neuropeptides. These include morphine-like compounds - endogenous opiates(beta-endorphin, dynorphin, various enkephalins). These substances can be considered so-called endogenous analgesics. These chemicals have an inhibitory effect on the neurons of the pain system, activate anti-pain neurons, modulate the activity of higher nerve centers pain sensitivity. The content of these anti-pain substances in the central nervous system decreases with the development of pain syndromes. Apparently, this explains the decrease in the threshold of pain sensitivity up to the appearance of independent pain sensations in the absence of a painful stimulus.It should also be noted that in the anti-pain system, along with morphine-like opiate endogenous analgesics, well-known brain mediators such as serotonin, norepinephrine, dopamine, gamma-aminobutyric acid(GABA), as well as hormones and hormone-like substances - vasopressin (antidiuretic hormone), neurotensin. Interestingly, the action of brain mediators is possible both at the level of the spinal cord and the brain. Summarizing the above, we can conclude that turning on the anti-pain system allows us to weaken the flow of pain impulses and reduce pain. If any inaccuracies occur in the operation of this system, any pain can be perceived as intense.
Thus, all pain sensations are regulated by the joint interaction of the nociceptive and antinociceptive systems. Only their coordinated work and subtle interaction allows us to adequately perceive pain and its intensity, depending on the strength and duration of exposure to the irritating factor.
Every person, starting from the very early age, from time to time experiences pain in one point or another of his body. We encounter a variety of pain sensations throughout our lives. And sometimes we don’t even think about what pain is, why does it occur and what does it signal?
What is pain
Various medical encyclopedias give approximately the following (or very similar) definition of pain: “an unpleasant sensation or suffering caused by irritation of special nerve endings in damaged or already damaged tissues of the body.” The mechanisms of pain at the moment have not yet been fully studied, but one thing is clear to doctors: pain is a signal that our body gives in the event of certain disorders, pathologies, or the threat of their occurrence.
Types and causes of pain
Pain can vary greatly. And in medical literature, and in everyday conversations you can find many different definitions nature of the pain: “cutting”, “stabbing”, “piercing”, “aching”, “pressing”, “dull”, “pulsating”... And this is not a complete list. But these are rather subjective characteristics of pain.
And scientific classification divides pain primarily into two large groups: acute and chronic. Or, as they are sometimes called, physiological and pathological.
Acute or physiological pain is short-term, and its cause, as a rule, is easily identified. Acute pain is usually clearly localized in a specific place in the body, and goes away almost immediately after the cause of it is eliminated. For example, acute pain occurs during injuries or various acute diseases.
Chronic or pathological pain bothers a person for a long time, and its causes are not always obvious. Almost always, chronic pain is caused by some long-term pathological processes. But determining which ones exactly is sometimes very difficult.
It should be noted that in some cases a person feels pain in a completely different place than the one that is affected. In this case, they talk about referred or radiating pain. The so-called phantom pain deserves special mention when a person feels it in a missing (amputated) or paralyzed limb.
There are also psychogenic pain, the cause of which is not organic lesions, A mental disorders, strong emotional experiences, serious psychological problems: depression, hypochondria, anxiety, stress and others. They often arise as a result of suggestion or autosuggestion (usually involuntary). Psychogenic pain is always chronic.
But, whatever the nature of the pain, it is always (with the possible exception of some cases of phantom pain) is a signal of some kind of trouble in the body. And therefore, in no case should you ignore even the slightest pain. Pain is one of the main components of our defense system. With its help, the body tells us: “something is wrong in me, take action urgently!” This also applies to psychogenic pain, only in this case the pathology must be sought not in the anatomical or physiological, but in the mental sphere.
Pain as a symptom of various diseases
So, pain signals some kind of disturbance in the body. In other words, it is a symptom of certain diseases or pathological conditions. Let's find out in more detail what pain in certain points of our body indicates, and what diseases they arise from.
Of all sensory processes, the most painful is the sensation of pain.
Pain - mental condition, arising as a result of super-strong or destructive effects on the body when its existence or integrity is threatened.
Clinical significance of pain as a symptom of disruption of the normal course physiological processes is important, since a number of pathological processes of the human body make themselves felt in pain even before the appearance 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 dependent 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 one’s painful sensations.
The sensation of pain usually appears with the onset of the disease, activation or progression of the 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 the pain by any means (taking various medications, surgery, any procedures to relieve the pain). They are especially hard to worry about paroxysmal pain at chronic diseases, often the reaction to them 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.
Patients suffering from severe pain need attentive and caring attention to their complaints and requests. Pain debilitates the patient more than any other disorder.
Pain represents an opportunity for the body to communicate to the subject that something bad has happened. Pain draws our attention to burns, fractures, sprains and advises us to be careful. There are a small number of people who are born without the ability to feel pain, they can endure the most severe injuries. As a rule, they die in early adulthood. Their joints wear out from excessive load, since without feeling discomfort from staying in the same position for a long time; they do not change their body position for a long time. Without pain symptoms, infectious diseases that go undetected in time and various injuries to parts of the body occur in a more acute form. But there are many more people who feel chronic pain(constant or periodic pain in the back, head, arthritis, cancer).
Nociceptive sensitivity(from Lat. notion - I cut, I damage) - a form of sensitivity that allows the body to recognize influences that are harmful to it. Nociceptive sensitivity can be subjectively presented in the form of pain, as well as in the form of various interoreceptive sensations, such as heartburn, nausea, dizziness, itching, numbness.
Painful sensations arise as a response of the body to such influences that can lead to a violation of its integrity. Characterized by pronounced negative emotional coloring and vegetative changes (increased heart rate, dilated pupils). In relation to pain sensitivity sensory adaptation practically absent.
Pain sensitivity determined by pain thresholds, among which are:
The lower one, which is represented by the magnitude of irritation at the first appearance of pain,
The upper one, which is represented by the magnitude of irritation at which pain becomes unbearable.
Pain thresholds vary depending on the general condition of the body and cultural stereotypes. Thus, women are more sensitive to pain during periods during ovulation. In addition, they are more sensitive to electrical stimulation than men, but have the same sensitivity to extreme thermal stimulation. Representatives of traditional ethnic groups are more resistant to pain.
Unlike vision, for example, pain is not localized to any specific nerve fiber that connects the receptor to the corresponding part of the cerebral cortex. There is also no single type of stimulus that causes pain (like, say, light irritates vision), and there are no special pain receptors (like the rods and cones of the retina). Stimuli that cause pain, in small doses, can also cause other sensations, such as a feeling of warmth, cold, smoothness or roughness.
Theories of pain. There were two alternative positions in the interpretation of the specificity of pain reception. One position was formed by R. Descartes, who believed that there are specific pathways coming from specific pain receptors. The more intense the flow of impulses, the more pain. Another position was presented, for example, by Goldscheider (1894), who denied the existence of both specific pain receptors and specific pathways pain conduction. Pain occurs whenever the brain receives too much stimulus from other modalities (cutaneous, auditory, etc.). It is currently believed that there are still specific pain receptors. Thus, in Frey's experiments, it was proven that there are special pain points on the surface of the skin, the stimulation of which does not cause any other sensations other than pain. These pain points are more numerous than pressure or temperature tender points. In addition, the skin can be made insensitive to pain using morphine, but other types of skin sensitivity are not affected. Free nerve endings, also located in the internal organs, act as nociceptors.
Pain signals are transmitted through the spinal cord to the nuclei of the thalamus and then to the neocortex and limbic system. Along with the nonspecific mechanisms of pain, which are activated when any afferent nerve conductors are damaged, there is a special nervous apparatus for pain sensitivity with special chemoreceptors that are irritated by kinins formed during the interaction of blood proteins with damaged tissues. Kinins can be blocked by painkillers (aspirin, pyramidon).
It’s interesting how painful sensations are remembered. Experiments show that after medical procedures people forget about the duration of pain. Instead, the moments of the strongest and final pain sensations are recorded in memory. D. Kahneman and his colleagues established this when they asked participants to put one hand in ice water that caused pain and hold it in it for 60 seconds, and then the other in the same water for 60 seconds, plus another 30 seconds, but During these 30 seconds the water no longer caused such severe pain. And when the experiment participants were asked which procedure they would like to repeat, the majority wanted to repeat a longer procedure, when the pain, although it lasted longer, subsided at the end of the procedure. When patients recalled the pain experienced during a rectal examination a month later, they also better remembered the last (as well as the most painful) moments, rather than the total duration of the pain. This leads to the conclusion that it is better to slowly ease the pain during a painful procedure than to abruptly end the procedure at the most painful moment. In one experiment, a doctor did this during a rectal examination procedure - he extended the procedure by one minute and made sure that during this time the patient’s pain decreased. And although an additional minute of discomfort did not reduce the total duration of pain during the procedure, patients later recalled this procedure as less painful than one that lasted less time but ended at the most painful moment.
Types of pain. It has long been noted that consciously inflicting additional pain on oneself helps reduce the subjective strength of pain. For example, Napoleon, who suffered from kidney stones, interrupted this pain by burning his hand in the flame of a candle. This raises the question of what should probably be said about different types pain.
It has been found that there are two types of pain:
Pain, transmitted by large-diameter fast-conducting nerve fibers (L-fibers), is sharp, distinct, fast-acting, and appears to originate from specific areas of the body. This warning system body, indicating that it is urgent to remove the source of pain. This type of pain can be felt if you prick yourself with a needle. The warning pain quickly disappears.
The second type of pain is also transmitted by slowly conducting nerve fibers (S-fibers) of small diameter. It's slow, aching, Blunt pain, which is different widespread and very unpleasant. This pain intensifies if the irritation is repeated. It is a pain resembling system it signals to the brain that the body has been damaged and movement must be restricted.
Although there is no generally accepted theory of pain control gate theory (or sensory gating), created by psychologist R. Melzack and biologist P. Wall (1965, 1983), is considered as the most substantiated. In accordance with it, it is believed that the spinal cord has a kind of nerve “gate” that either blocks pain signals or gives them the opportunity (relief) to go to the brain. They noticed that one type of pain sometimes suppresses another. Hence the hypothesis was born that pain signals from various nerve fibers the same nerve “gates” pass through the spinal cord. If the gate is “closed” by one pain signal, other signals cannot pass through it. But how are the gates closed? Signals transmitted by large, fast-acting nerve fibers of the warning system appear to close the spinal pain gate directly. This prevents the slow pain "reminder system" from reaching the brain.
Thus, if tissue is damaged, small fibers are activated, opening the neural gates, and pain is felt. Activation of large fibers causes the pain gate to close, causing pain to subside.
R. Melzack and P. Wall believe that the gate control theory explains the analgesic effects of acupuncture. Clinics use this effect by applying a weak electrical current to the skin: this stimulation, felt only as a slight tingling sensation, can significantly reduce more excruciating pain.
In addition, pain can be blocked at the level of the spinal hilum due to an increase in general arousal and the appearance of emotions, including during stress. These cortical processes activate fast L-fibers and thereby block access for the transmission of information from S-fibers.
Also, the gate to pain can be closed with the help of information that comes from the brain. Signals that go from the head to spinal cord, help explain examples psychological impact for pain. If different ways If you divert attention from pain signals, the sensation of pain will be significantly less. Injuries sustained in sports games, may not be noticed until you shower after the game. While playing basketball in 1989, Ohio State University player J. Burson broke his neck, but continued to play.
This theory also helps explain the occurrence of phantom pain. Just as we see a dream with our eyes closed or hear a ringing in complete silence, 7 out of 10 amputees have pain in their amputated limbs (in addition, it may seem to them that they are moving). This phantom limb sensation suggests that (as in the examples with vision and hearing) the brain may misunderstand the spontaneous activity of the central nervous system that occurs in the absence of normal sensory stimulation. This is explained by the fact that after amputation, partial regeneration of nerve fibers occurs, but primarily of the S-fiber type, but not of the L-fiber. Because of this, the spinal gate always remains open, which leads to phantom pain.
Pain control. One way to relieve chronic pain is to stimulate (massage, electromassage or even acupuncture) large nerve fibers so that they close the path to pain signals. If you rub the skin around the bruise, you create additional irritation, which will block some of the pain signals. Ice on the bruised area not only reduces swelling, but also sends cold signals to the brain that close the pain gate. Some people with arthritis may wear a small, portable electrical stimulator near the affected area. When it irritates the nerves in a sore spot, the patient feels vibration rather than pain.
Depending on the symptoms in clinical settings choose one or more methods of pain relief: medications, surgical intervention, acupuncture, electrical stimulation, massage, gymnastics, hypnosis, auto-training. Thus, the widely known preparation according to the Lamaze method (preparation for childbirth) includes several of the above-mentioned techniques. Among them are relaxation (deep breathing and muscle relaxation), counterstimulation ( light massage), distraction (concentrating attention on some pleasant object). After E. Worthington (1983) and his colleagues conducted several such sessions with women, the latter more easily tolerated discomfort associated with holding hands in ice water. The nurse can distract the attention of patients who are afraid of injections, kind words and asking to look somewhere as he inserts the needle into the body. Beautiful view looking at a park or garden from a hospital ward window also has a positive effect on patients, helping them to forget unpleasant feelings. When R. Ulrich (1984) became familiar with medical records patients at the Pennsylvania Hospital, he concluded that patients who were treated in rooms overlooking the park required less medication and left the hospital faster than those who lived in cramped rooms whose windows faced a blank brick wall.
