Painful sensations: acute pain with. Internal organs - what hurts? Unpleasant sensations in the legs

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 stated above, the classification committee of the International Association for the Study of Pain defines pain as “an unpleasant sensory and emotional experience associated with existing or potential tissue damage 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 important role 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 well-defined painful irritations of superficial or deep tissues and internal organs, dysfunction smooth muscle. Acute 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 sharp 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. Chronic pain in recent years began to be considered not only as a syndrome, but also as a separate nosology. Its formation and maintenance depends largely on the complex psychological factors rather than on the nature and intensity of peripheral nociceptive effects. 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 possible reasons contributing to the chronicity of pain is treatment that is inadequate to the cause and pathogenesis 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, joint syndrome, damage to the skin, ligaments, muscles, etc.). Neuropathic pain occurs due to damage various departments(peripheral and central) somatosensory nervous system.

Nociceptive pain syndromes are most often acute (burn, cut, bruise, abrasion, fracture, sprain), but can also be chronic (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”. Good in the treatment of nociceptive pain 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.

The causes of neuropathic pain can be damage to the afferent somatosensory system at any level, from peripheral sensory nerves to the cerebral cortex, 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 (hypoesthesia, 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 of the 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, there are pain syndromes in the clinical picture of 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 conduction 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. For example, an inflammatory process can lead to activation of pain receptors. 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 the neurons of the dorsal 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 ANS of the brain 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) is 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 the autonomic, motor, neuroendocrine, emotional and behavioral manifestations of pain associated with pain. This circumstance allows us to consider them as the most important system, which 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 with best side Non-steroidal anti-inflammatory drugs (NSAIDs) and opioid analgesics have proven themselves. For neuropathic pain, the use of antidepressants, anticonvulsants, local anesthetics, as well as potassium channel blockers.

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, studies in recent years have 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. Most widespread among them received lidocaine, novocaine, articaine and bupivacaine. The mechanism of action of local anesthetics is associated with blocking Na + channels on the membrane 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).

Anticonvulsants available today for the treatment of pain have different points of application. 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 narcotic analgesics, 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. IN lately In order to relax muscles in the treatment of myofascial pain syndromes, injections of botulinum toxin type A are used. 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, at the level interneurons spinal cord, polysynaptic transmission of excitation is suppressed. Since it is this mechanism that is responsible for excess muscle tone, 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 (traumatic injuries of the 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 due to stabilization membrane potential peace.

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. EXTREME CONDITIONS

Compiled by: Doctor of Medical Sciences, Professor D.D. Tsyrendorzhiev

Candidate of Medical Sciences, Associate Professor F.F.Mizulin

Discussed at the methodological meeting of the Department of Pathophysiology "____" _______________ 1999

Protocol No.

Lecture outline

I.PAIN, DEVELOPMENT MECHANISMS,

GENERAL CHARACTERISTICS AND TYPES

Introduction

Since time immemorial, people have looked at pain as a harsh and inevitable companion. A person does not always understand that she is a faithful guardian, a vigilant sentinel of the body, a constant ally and an active assistant to the doctor. It is pain that teaches a person caution, forces him to take care of his body, warning him of impending danger and signaling illness. In many cases, pain allows us to assess the degree and nature of the violation of the integrity of the body.

"Pain is watchdog health,” they said in Ancient Greece. And in fact, despite the fact that pain is always painful, despite the fact that it depresses a person, reduces his performance, deprives him of sleep, it is necessary and useful to a certain extent. The feeling of pain protects us from frostbite and burns, and warns us of impending danger.

For a physiologist, pain comes down to the affective, emotional coloring of a sensation caused by rough touch, heat, cold, blow, injection, wound. For a doctor, the problem of pain can be solved relatively simply - it is a warning about dysfunction. Medicine views pain in terms of the benefits it brings to the body, without which the disease can become incurable even before it can be detected.

To defeat pain, to destroy in the very bud this sometimes incomprehensible “evil” that haunts all living things is a constant dream of humanity, rooted in the depths of centuries. Throughout the history of civilization, thousands of remedies have been found to relieve pain: herbs, medicines, physical influences.

The mechanisms of pain are both simple and incredibly complex. It is no coincidence that disputes between representatives of different specialties studying the problem of pain still do not subside.

So what is pain?

1.1. The concept of pain and its definitions

Pain- a complex concept that includes a peculiar sensation of pain and a reaction to this sensation with emotional stress, changes in the functions of internal organs, motor unconditioned reflexes and volitional efforts aimed at getting rid of the pain factor.

Pain is realized by a special system of pain sensitivity and emotional structures of the brain. It signals about impacts causing damage, or about existing damage resulting from the action of exogenous damaging factors or the development of pathological processes in tissues.

Pain is the result of irritation in the system of receptors, conductors and pain sensitivity centers at different levels of the uneven system. The most severe pain syndromes occur when the nerves and their branches of the sensitive dorsal roots of the spinal cord and the roots of the sensory cranial nerves and the membranes of the brain and spinal cord and, finally, the optic thalamus are damaged.

There are pains:

Local pain– localized at the site of development of the pathological process;

Projection pain are felt along the periphery of the nerve when its proximal area is irritated;

Irradiating they call pain in the area of innervation of one branch in the presence of an irritating focus in the area of another branch of the same nerve;

Referred pain occur as a viscerocutaneous reflex in diseases of internal organs. In this case, a painful process in an internal organ, causing irritation of afferent autonomic nerve fibers, leads to the appearance of pain in a certain area of the skin associated with the somatic nerve. The areas where viscerosensory pain occurs are called Zakharyin-Ged zones.

Causalgia(burning, intense, often unbearable pain) is a special category of pain that sometimes occurs after injury to a nerve (usually the median nerve, rich in sympathetic fibers). Causalgia is based on partial damage to the nerve with incomplete disruption of conduction and phenomena of irritation of autonomic fibers. At the same time, border nodes are involved in the process sympathetic trunk and thalamus.

Phantom pain– sometimes appear after amputation of a limb. The pain is caused by irritation of the nerve scar in the stump. Painful stimulation is projected by consciousness into those areas that were previously associated with these cortical centers, normally.

In addition to physiological pain, there is also pathological pain– having disadaptive and pathogenetic significance for the body. Insurmountable, severe, chronic pathological pain causes mental and emotional disorders and disintegration of the central nervous system, often leading to suicidal attempts.

Pathological pain has a number characteristic features, which are not present in physiological pain.

Signs of pathological pain include:

causalgia;

hyperpathy (preservation severe pain after the cessation of provoking stimulation);

hyperalgesia (intense pain with nociative irritation of the damaged area - primary hyperalgesia); either neighboring or distant zones - secondary hyperalgesia):

allodynia (provocation of pain under the action of non-nociceptive stimuli, referred pain, phantom pain, etc.)

Peripheral sources irritations that cause pathologically increased pain may be tissue nociceptors. When they are activated - during inflammatory processes in tissues; when compressed by a scar or overgrown bone tissue of the nerves; under the influence of tissue decay products (for example, tumors); under the influence of biologically active substances produced in this case, the excitability of nociceptors significantly increases. Moreover, the latter acquire the ability to respond even to ordinary, non-nociative influences (the phenomenon of receptor sensitization).

Central source pathologically increased pain may be altered formations of the central nervous system, which are part of the pain sensitivity system or modulate its activity. Thus, aggregates of hyperactive nociceptive neurons that form the GPUV in the dorsal organs or in the caudal nucleus of the trigeminal nerve serve as sources that involve the pain sensitivity system in the process. This kind of pain of central origin also occurs with changes in other formations of the pain sensitivity system - for example, in the reticular formations of the medulla oblongata, in the thalamic nuclei, etc.

All these centrally originating pain information appears when these formations are affected by trauma, intoxication, ischemia, etc.

What are the mechanisms of pain and its biological significance?

1.2. Peripheral mechanisms of pain.

Until now, there is no consensus on the existence of strictly specialized structures (receptors) that perceive pain.

There are 2 theories of pain perception:

Proponents of the first theory, the so-called “specificity theory”, formulated at the end of the 19th century by the German scientist Max Frey, recognize the existence in the skin of 4 independent perceiving “devices” - heat, cold, touch and pain - with 4 separate impulse transmission systems in the central nervous system.

Adherents of the second theory - the “intensity theory” of Goldscheider and compatriot Frey - admit that the same receptors and the same systems respond, depending on the strength of irritation, to both non-painful and painful sensations. The feeling of touch, pressure, cold, heat can become painful if the irritant that causes it is excessively strong.

Many researchers believe that the truth is somewhere in the middle and most modern scientists recognize that the feeling of pain is perceived by the free endings of nerve fibers that branch into surface layers skin. These endings can have a wide variety of shapes: hairs, plexuses, spirals, plates, etc. They are pain receptors or nociceptors.

The transmission of the pain signal is transmitted by 2 types of pain nerves: thick myelinated nerve fibers of type A, through which signals are transmitted quickly (at a speed of about 50-140 m/s) and, thinner unmyelinated nerve fibers of type C - signals are transmitted much more slowly (at a speed of approximately 0.6-2 m/s). The corresponding signals are called fast and slow pain. Fast burning pain is a reaction to injury or other damage and is usually strictly localized. Slow pain is often a dull ache and is usually less clearly localized.

Pain from a medical point of view

From a medical point of view, pain is:

reaction to this sensation, which is characterized by a certain emotional coloring, reflex changes in the functions of internal organs, unconditioned motor reflexes, as well as volitional efforts aimed at getting rid of the pain factor.
an unpleasant sensory and emotional experience associated with real or perceived tissue damage, and at the same time a reaction of the body that mobilizes various functional systems to protect it from the effects of pathogenic factors.

Prolonged pain is accompanied by changes in physiological parameters (blood pressure, pulse, pupil dilation, changes in hormone concentrations).

International definition

Nociception is a neurophysiological concept that refers to the perception, conduction and central processing of signals about harmful processes or influences. That is, this physiological mechanism transmission of pain, and it does not affect the description of its emotional component. It is important that the transmission of pain signals in the nociceptive system itself is not equivalent to felt pain.

Types of physical pain

Acute pain

Acute pain is defined as pain of short duration of onset with an easily identifiable cause. Acute pain is a warning to the body about the current danger of organic damage or disease. Often persistent and acute pain is also accompanied by aching pain. Acute pain is usually concentrated in a specific area before it somehow spreads wider. This type of pain is usually highly treatable.

Chronic pain

Chronic pain was originally defined as pain that lasts about 6 months or more. It is now defined as pain that persistently persists beyond the appropriate length of time during which it would normally end. It is often more difficult to heal than acute pain. Particular attention is required when addressing any pain that has become chronic. In exceptional cases, neurosurgeons may perform complex operation to remove parts of a patient's brain to treat chronic pain. Such an intervention can relieve the patient from the subjective sensation of pain, but since signals from the pain site will still be transmitted through neurons, the body will continue to react to them.

Skin pain

Skin pain occurs when the skin or subcutaneous tissue is damaged. Cutaneous nociceptors end just below the skin, and thanks to high concentration nerve endings provide a highly precise, localized sensation of pain of short duration.

Somatic pain

Somatic pain occurs in ligaments, tendons, joints, bones, blood vessels, and even the nerves themselves. It is determined by somatic nociceptors. Due to the lack of pain receptors in these areas, they produce a dull, poorly localized pain that is longer lasting than that of skin pain. This includes, for example, sprained joints and broken bones.

Inner pain

Internal pain arises from the internal organs of the body. Internal nociceptors are located in organs and internal cavities. An even greater lack of pain receptors in these areas of the body leads to more dull and prolonged pain, compared to somatic pain. Internal pain is particularly difficult to localize, and some internal organic injuries represent “attributed” pain, where the sensation of pain is attributed to an area of the body that is in no way related to the site of the injury itself. Cardiac ischemia (insufficient blood supply to the heart muscle) is perhaps the best known example of attributable pain; the sensation may be located as a separate feeling of pain just above the chest, in the left shoulder, arm or even in the palm. The pain attributed may be explained by the discovery that pain receptors in internal organs also excite spinal neurons that are excited by skin lesions. Once the brain begins to associate the firing of these spinal neurons with stimulation of somatic tissues in the skin or muscle, pain signals coming from the internal organs begin to be interpreted by the brain as originating from the skin.

Phantom pain

Phantom limb pain is a sensation of pain that occurs in a lost limb or in a limb that is not felt through normal sensations. This phenomenon is almost always associated with cases of amputation and paralysis.

Neuropathic pain

Neuropathic pain (“neuralgia”) may occur as a result of damage or disease to the nerve tissues themselves (eg, toothache). This may interfere with the sensory nerves' ability to transmit correct information thalamus (department diencephalon), and hence the brain misinterprets painful stimuli, even if there are no obvious ones physiological reasons pain.

Psychogenic pain

Psychogenic pain is diagnosed in the absence of an organic disease or in the case when the latter cannot explain the nature and severity of the pain syndrome. Psychogenic pain is always chronic and occurs against the background of mental disorders: depression, anxiety, hypochondria, hysteria, phobias. In a significant proportion of patients, psychosocial factors play an important role (dissatisfaction with work, desire to obtain moral or material benefits). Particularly strong links exist between chronic pain and depression.

Pathological pain

Pathological pain- altered perception of pain impulses as a result of disorders in the cortical and subcortical parts of the central nervous system.

Disturbances can occur at any level of the nociceptive system, as well as when the connection between nociceptive ascending structures and the antinociceptive system is disrupted.

Heartache

Mental pain is a specific mental experience that is not associated with organic or functional disorders. Often accompanied by depression and mental illness. Most often it is long-lasting and associated with the loss of a loved one.

Physiological role

Despite its unpleasantness, pain is one of the main components protective system body. This the most important signal about tissue damage and the development of the pathological process, a constantly operating regulator of homeostatic reactions, including their higher behavioral forms. However, this does not mean that pain has only protective properties. Under certain conditions, having played its informational role, pain itself becomes part of a pathological process, often more dangerous than the damage that caused it.

One hypothesis is that pain is not specific physical sensation, and there are no special receptors that perceive only pain stimulation. The appearance of a feeling of pain can be caused by irritation of any type of receptors, if the force of irritation is sufficiently great.

According to another point of view, there are special pain receptors characterized by high threshold perception. They are excited only by stimuli of damaging intensity. All pain receptors do not have specialized endings. They are present in the form of free nerve endings. There are mechanical, thermal and chemical pain receptors. They are located in the skin and in internal surfaces such as the periosteum or articular surfaces. Deeply located internal surfaces are weakly connected to pain receptors, and therefore sensations of chronic, aching pain transmitted only if organic damage occurs directly in this area of the body.

It is believed that pain receptors do not adapt to external stimuli. However, in some cases, the activation of pain fibers becomes excessive, as if painful stimuli continue to be repeated, leading to a condition called hypersensitivity to pain (hyperalgesia). In fact, there are people with different pain sensitivity thresholds. And this may depend on the emotional and subjective characteristics of the human psyche.

Nociceptive nerves contain primary fibers of small diameter that have sensory endings in various organs and fabrics. Their sensory endings resemble small branched bushes.

The two main classes of nociceptors, Aδ- and C-fibers, transmit fast and slow pain sensations, respectively. The class of Aδ-myelinated fibers (covered with a thin myelin coating) conduct signals at speeds of 5 to 30 m/s and serve to transmit signals of rapid pain. This type of pain is felt within one tenth of a second from the moment the painful stimulus occurs. Slow pain, whose signals travel through slower, unmyelinated (“naked”) C-fibers at a velocity of 0.5 to 2 m/s, is an aching, throbbing, burning pain. Chemical pain (whether it be poisoning through food, air, water, accumulation of alcohol, drugs, medications or radiation contamination in the body, etc.) is an example of slow pain.

Other points of view

The study of pain has expanded in recent years to various areas from pharmacology to psychology and neuropsychiatry. It was previously impossible to even imagine that fruit flies would be used as an object for pharmacological studies of pain. Some psychiatrists are also trying to use pain to find a neurological "substitute" for human awareness, since pain has many subjective psychological aspects beyond pure physiology.

Interestingly, the brain itself lacks nociceptive tissue, and therefore cannot feel pain. Thus, headaches cannot possibly originate in the brain itself. Some suggest that the membrane surrounding the brain and spinal cord, which is called the dura mater, is supplied with nerves with pain receptors, and these dural (related to the dura mater) are stimulated meninges) nociceptors, and they are likely to be involved in the “production” of headaches.

Alternative medicine

Surveys conducted National Center US Complementary and Alternative Medicine (NCCAM) study found that pain is a common reason why people turn to complementary and alternative medicine. CAM). Among American adults who used C.A.M. in 2002, 16.8% wanted to cure back pain, 6.6% - neck pain, 4.9% - arthritis, 4.9% - joint pain, 3.1% - headache and 2.4% were trying to cope with recurrent pain.

One such alternative, Traditional Chinese Medicine, views pain as a blockage of "Qi" energy, which is similar to resistance in an electrical circuit, or as "blood stagnation", which is theoretically similar to dehydration, which impairs the body's metabolism. The traditional Chinese practice, acupuncture, has been found to be more effective for non-traumatic pain than for pain associated with injury.

In recent decades, there has been a trend to prevent or treat pain and illness that create painful sensations with proper nutrition. This approach sometimes involves taking dietary supplements (dietary supplements) and vitamins in huge quantities, which from a medical point of view is considered a harmful attempt at self-medication. The work of Robert Atkins and Earl Mindel pays much attention to the relationship between the activity of amino acids and the health of the body. For example, they claim that the essential amino acid DL-phenylalanine promotes the production of endorphins and has a non-addictive analgesic effect. But in any case, they urge you to always consult a doctor.

Notes

Links

Virtual reality relieves phantom pain Compulent

Emotional Processes
Emotions
Feelings	Agape · Antipathy · Gratitude · Reverence · Guilt · Attraction · Infatuation · Admiration · Hostility · Indignation · Pity · Envy · Interest · Love · Tenderness · Hatred · Rejection · Resentment · Disgust · Contempt · Disdain · Attachment · Irritation · Frustration · Repentance · Jealousy · Sympathy · Sorrow ·

Nocigenic (somatic) pain is pain that occurs when nociceptors of the skin, mucous membranes, deep tissues (in the musculoskeletal system) or internal organs are irritated. The nerve (nociceptive) impulses arising in this case, following the ascending nociceptive pathways, reach the higher parts of the nervous system and are reflected by consciousness, as a result the sensation of pain is formed. Somatic pain is usually well localized. Examples: pain due to burns, skin damage (scratches, injuries), joint pain, muscle (myofascial) pain, pain due to sprains, bone fractures.

Visceral pain is pain originating from the soft tissues (cavitary) of internal organs. Such pain is the result of irritation of receptors localized in the walls of internal organs. Examples: pain in the heart (with angina), in chest(against the background of colds, tuberculosis), stomach pain ( peptic ulcer), intestines (with constipation), liver (hepatic colic), pancreas (with pancreatitis), kidneys and bladder(renal colic), etc. Neuropathic pain is pain resulting from damage to the peripheral or central nervous system. Such pain is not explained by irritation of nociceptors (the sensation of pain occurs even in healthy organ). Pain sensations are usually noted in response to low-intensity (normally not causing pain) irritants. For example, a light touch, a puff of air or combing your hair with trigeminal neuralgia causes a “pain volley” in response. Such pain, in particular, can occur in conditions of inflammation, damage to nerves or other components of the nervous system. Damage to the nerves or the influence of inflammatory factors on them (edema, inflammatory mediators, acidification of the intercellular fluid at the site of inflammation, etc.) lead to an increase in their sensitivity (excitability) and conductivity. Examples: neuralgia trigeminal nerve(against the background of inflammation), toothache (against the background of infection and inflammation), joint pain (against the background of rheumatoid arthritis), lower back pain (for example, against the background of herniated discs in the lumbar region, causing compression of the nerve roots), etc. Psychogenic pain (“phantom”, or psychalgia, or somatoform pain) - pain caused by mental, emotional or behavioral factors. Such pain, as a rule, is poorly treated with conservative methods, in particular with the use of analgesics. If they are accurately established, the prescription of antidepressants and other psychotropic drugs is required. Examples: pain after amputation surgery, some cases of headaches, back pain and stomach pain