What is nociceptive pain? Nociceptive pain in the practice of a neurologist: diagnostic algorithms, adequacy and safety of therapy. Characteristics of nociceptive somatic pain.
Nociceptive pain is a syndrome that every person has encountered at least once in their life. This term refers to pain caused by a damaging factor. It is formed when there is an influence on some tissue. The sensations are acute, in medicine they are called epicritic. Accompanied by excitation of peripheral receptors responsible for the perception of pain. Signals are sent to the central nervous system. This impulse transmission explains the localization of the onset of pain.
Physiology
Nociceptive pain appears if a person is injured, if an inflammatory focus develops, or ischemic processes occur in the body. This syndrome accompanies degenerative tissue changes. The area of localization of the pain syndrome is precisely defined and obvious. When the offending factor is removed, the pain (usually) disappears. To weaken it, you can use classical anesthetics. The short-term effect of the drugs is enough to stop the nociceptive phenomenon.
Nociceptive pain is physiologically necessary so that the body receives a timely warning about the unfavorable state of a certain area. This phenomenon is considered protective. If the pain is observed for a long period of time, if an aggressive factor is excluded, but the pain still bothers the person, it cannot be regarded as a signal. This phenomenon is no longer a symptom. It must be assessed as a disease.
From statistics it is known that most often a pain syndrome of this type in the form of a chronicle is formed when a person has arthritis. Muscular and skeletal pain of this nature is not uncommon.
What happens?
There are two main types of pain: nociceptive and neuropathic. The division into these categories is due to the pathogenesis of the phenomenon, the specific mechanisms through which the syndromes are formed. To assess the nociceptive phenomenon, it is necessary to analyze the nature of the pain and assess the scale, determine which tissues, where and how badly damaged. The time factor is no less important for analyzing the patient’s condition.
Nociceptive soreness is associated with stimulation of nociceptors. These can be activated if the skin is deeply damaged, the integrity of bones, deep tissues, and internal organs is compromised. Studies of intact organisms have shown the formation of the type of pain in question immediately upon the appearance of a local stimulus. If the stimulus is quickly removed, the syndrome goes away immediately. If we consider nociceptive pain in relation to surgical practices, we have to recognize a relatively long-lasting effect on the receptors, accompanied in most cases by a large-scale working area. These aspects explain why the risk of persistent pain and the formation of an inflammatory focus is increased. An area of chronic pain syndrome may appear with the consolidation of this phenomenon.
About categories
There is pain: nociceptive somatic, visceral. The first is detected if a skin inflammatory area is formed, the skin or muscles are damaged, if the integrity of fascial and soft tissues is damaged. Somatic cases include a situation of damage and inflammation in the articular and bone areas, tendons. The second type of phenomenon occurs when damage is caused to the internal cavitary membranes and hollow, parenchymal organic structures. The hollow elements of the body may stretch excessively, and a spasmodic phenomenon may form. Such processes can affect the vascular system. Visceral pain appears during an ischemic process, an inflammatory focus and swelling of a certain organ.
The second category of pain is neuropathic. In order to more accurately understand the essence of nociceptive pain syndrome, it is necessary to describe this class in order to know the differences. Neuropathic appears if the peripheral or central blocks of the NS are affected.
Soreness has an additional psychological aspect. It is human nature to fear the approach of pain. This is a source of stress and a factor that can provoke depression. There is a possibility of a psychological phenomenon of unresolved pain. Pain syndrome provokes sleep disturbances.
Nuances of phenomena
As can be seen from the above, types of nociceptive pain (somatic, visceral) have different neurological mechanisms. This fact is explained scientifically and is important for researchers. The differences in the mechanisms of pain formation are of particular importance for clinical practice. A somatic phenomenon, caused by irritation of nociceptors of the afferent somatic type, is clearly localized in a tissue area that is damaged due to some factor. The use of a classic pain reliever can quickly alleviate the patient's condition. The intensity of the syndrome dictates the need to choose an opioid painkiller or a non-opioid one.
Visceral nociceptive pain is caused by specific structural features of internal organs, and a particularly important aspect is the innervation of such systems. It is known that the provision of performance due to nerve fibers differs for different internal structures. Many internal organs have receptors whose activation due to damage does not lead to awareness of the stimulus. Sensory perception is not formed. The patient does not identify pain. The organization of the mechanisms of such pain (against the background of somatic pain) has fewer separating mechanisms of sensory transmission.
Receptors and their features
By studying what is characteristic of nociceptive pain of the visceral type, it was established that the receptors whose activity is necessary for sensory perception are interconnected. There is a phenomenon of autonomous regulation. Innervation of the afferent type, present in the internal organic structures of the body, is partially provided by indifferent structures. These are capable of going into an active state if the integrity of the organ is compromised. Their activation is observed during the inflammatory process. Receptors of this class are one of the elements of the body responsible for chronic visceral pain syndrome. Due to it, spinal reflexes are active for a long time. At the same time, the autonomous regulation is disrupted. The functionality of organs is impaired.
Violation of the integrity of the organ, the inflammatory process are the reasons due to which the classic secretory and motor activity patterns are disrupted. The environment in which receptors exist changes unpredictably and dramatically. These changes activate silent elements. Sensitivity of the area develops, visceral pain appears.
Pain and its sources
An important characteristic of nociceptive pain is whether it is of a somatic or visceral type. It is possible to transmit a signal from one damaged internal structure to another. There is a possibility of projection of somatic tissues. Hyperalgesia in the area where the damage is localized is considered primary pain; other types are classified as secondary, since they are not localized in the area where the damage is.
Visceral nociceptive pain occurs when mediators, substances that provoke pain, appear in the area where the damage is localized. There may be inadequate stretching of the muscle tissue or excessive contraction of this part of the hollow organ. In a parenchymal structure, the capsule in which the organ is enclosed may stretch. Smooth muscle tissues are subject to anoxia, while vascular and ligamentous tissues are subject to traction and compression. Visceral pain syndrome of the nociceptive type is formed during necrotic processes and the appearance of a focus of inflammation.
The listed factors are often encountered during intracavitary surgery. Operations of this class are especially traumatic and are more likely to lead to dysfunction and complications. Nociceptive pain studied in neurology is an important aspect, the study of which should provide new ways to improve methods and approaches to surgical intervention and pain relief.
Categories: visceral type
Visceral hyperalgesia is observed directly in the affected organ. This is possible in the case of an inflammatory focus or stimulation of nociceptors. The viscerosomatic form is fixed in the area of somatic tissues, which are affected by the projection of pain. Viscero-visceral is a format in which the pain syndrome spreads from one organ to another. The phenomenon is explained by the specific innervation of tissues. If it overlaps in some areas, the pain spreads to new parts of the body.
About drugs
Treatment of nociceptive pain involves the use of specialized medications developed for this purpose. If the syndrome is unexpected, appears suddenly, the sensations are acute, are caused by surgical procedures or the disease for which surgery is prescribed, you need to choose an analgesic, taking into account the root cause of the condition. The doctor must immediately think through a system of measures to eliminate the cause of the pathology.
If a person is supposed to be operated on, the situation is planned, it is important to predict the pain syndrome in advance and develop measures to prevent it. They take into account where the operation will be performed, how large the intervention is, how much tissue will be damaged, and what elements of the nervous system will have to be affected. Preventive protection from pain is required, which is realized through slowing down the firing of nociceptors. Pain relief measures are carried out before the surgeon intervenes.
Science and practice
It is known that nociceptive somatic pain occurs as a result of activation of nociceptors. Such elements of the body were first identified in 1969. Information about them appeared in scientific papers published by scientists Iggo and Perl. Research has shown that such elements are non-encapsulated endings. There are three types of elements. Excitation of a specific is explained by a stimulus affecting the body. There are: mechano-, thermo-, polymodal nociceptors. The first block of the chain of such structures is located in the ganglion. Afferents predominantly end up in the spinal structures through the dorsal roots.
Scientists, identifying what characteristics nociceptive somatic pain has, discovered the fact of transmission of nociceptor data. The main task of such information is to recognize the damaging influence with an accurate determination of the area. Due to such information, an attempt to avoid exposure is activated. The transmission of information about pain from the face and head is realized through the trigeminal nerve.
Syndromes: what are they?
To characterize nociceptive somatic pain, it is necessary to determine what pain syndrome has formed in a particular case. It can be psychogenic, somatogenic, neurogenic. Nociceptive syndrome is clinically divided into those following surgery or trauma, explained by oncology. There is also a syndrome associated with muscle, joint inflammation, and gallstones.
Possibly a psychogenic phenomenon. Such pain is not due to physical damage, but is associated with social influences and psychological effects. In practice, doctors are most often forced to deal with cases of a combined phenomenon, in which several forms of the syndrome are combined at once. In order to correctly formulate treatment tactics, you need to identify all types and record them in the patient’s personal chart.
Pain: acute or not?
One of the key characteristics of nociceptive somatic pain is temporary. Any pain syndrome can be chronic or acute. Acute is formed as a result of nociceptive influence: injury, illness, muscle dysfunction. The influence is possible due to disruption of the functionality of some internal organ. In most cases, this type of pain is accompanied by endocrine stress, neural. Its strength is directly determined by the aggressiveness of its influence on the body. Nociceptive pain of this type is observed during the birth of a child and against the background of an acute illness affecting internal structures. Its task is to identify which tissue is damaged, determine and limit the aggressive influence.
Considering what characteristics nociceptive somatic pain has, it should be recognized that most cases are characterized by the ability to resolve independently. If this does not happen with a certain course, the syndrome disappears due to treatment. The duration of storage is a matter of days, although less often the time frame extends to weeks.
About the chronicle
Speaking about what characteristics nociceptive somatic pain has, one of the first to mention is temporary. It is formed on the basis of the acute one. This usually happens if regenerative abilities are impaired or the patient received an incorrectly selected therapeutic program. The peculiarity of chronic pain of the nociceptive type is its ability to persist if the acute stage of the disease has resolved. It is customary to talk about a chronicle if enough time has passed, the person should have already been cured, but the pain syndrome is still bothersome. The period of formation of the chronicle is from a month to six months.
Finding out what is typical for nociceptive somatic pain of the chronic type, we found that the phenomenon is often formed due to the peripheral influence of nociceptors. There is a possibility of PNS and CNS dysfunction. In humans, the neuroendocrine response to stress factors is weakened, sleep disturbances and an affective state are formed.
Kryzhanovsky's theory
These scientists published two works devoted to the characteristics of pain. The first was released in 1997, the second in 2005. Determining what is characteristic of nociceptive somatic pain, he proposed dividing all cases of pain into pathological and physiological. Normally, pain is a physiological defense of the body, an adaptation reaction designed to exclude an aggressive factor. Pathological, however, has no protective functionality and interferes with adaptation. This phenomenon cannot be overcome, it is difficult for the body, leads to a violation of the psychological status and disorders of the emotional sphere. The activity of the central nervous system is disintegrated. People suffering from such pain are prone to suicide. Internal organs experience changes, deformations, structural damage, functionality and vegetative work are disrupted, and secondary immunity suffers.
Myological pain is not uncommon. This accompanies somatic pathologies and diseases of the nervous system.
About treatment
If the pain syndrome is characterized as nociceptive, the therapeutic program should include three aspects. It is important to limit the flow of information from the area of damage to the nervous system, slow down the production of algogens, their release into the body, and also activate antinociception.
Control of impulses from the area of the disorder is ensured by painkillers with a local effect. Currently, lidocaine and novocaine are most often used. Studies have shown that such active compounds block sodium channels present in neuronal membranes and processes. Activation of the sodium system is a prerequisite for the presence of an action potential and impulse.
To inhibit afferentation, it is necessary to use blockade approaches affecting spinal structures and the peripheral nervous system. In some cases, superficial anesthesia is recommended, sometimes infiltration. For control, central or regional blockade can be used. The latter involves stopping the activity of peripheral elements of the NS.
About the subtleties
Superficial anesthesia is necessary to prevent nociceptor activity. It is effective if the factor that provoked the pain is located in the skin, that is, superficial. General therapeutic and neurological practice allows infiltration of novocaine solution in concentrations from 0.25% to twice that. Local anesthesia with ointments and gel-like substances is allowed.
Infiltration anesthesia allows you to deliver an analgesic to the deep skin layers and muscles that support the skeleton. More often, “Procaine” is used for such purposes.
The regional format is implemented strictly by highly qualified specialists trained in this field. An incorrectly carried out event is highly likely to initiate apnea, an epilepsy-type seizure, and suppression of blood flow. In order to timely exclude and eliminate a complication, it is necessary to monitor the patient’s condition, as defined by the standard of general anesthesia. In medicine, the nerves between the ribs, cutaneous, radial, and median, which ensure the functioning of the elbow, are actively used. Sometimes intravenous anesthesia of the arm is indicated. For this event, they resort to technology developed by Beer.
Doctor, Candidate of Sciences Louis Urgelles-Loriaspecialist in neurology and neurophysiology
NEW CLASSIFICATION OF PAIN THERAPY
SUMMARYPhysiological Regulatory Medicine (PRM) is the latest achievement of integration between traditional and homeopathic medicine. In PRM, the principles of classical homeopathy are combined with an innovative therapeutic concept - with the goal of restoring the physiological state through the action of molecules (hormones, neuropeptides, interleukins and growth factors) in homeopathic dilutions that correspond to the physiological concentrations of the biological environment. This method is based on advanced data from the fields of homeopathy, homotoxicology, psycho-neuro-endocrine-immune (PNEI) direction and nutrition.
In this case, 4 types of pain are considered. The physiological type refers to the protection of vital functions. Nociceptive pain has an inflammatory origin, where COX-2 (COX-2) is partially stimulated by the proinflammatory interleukin IL-1ß; this type is modulated depending on the level of opposition between pro- and anti-inflammatory interleukins. Neuropathic pain results from disruption, compression, or dysfunction of peripheral nerves or the central nervous system; this is a deviation in the neurotransmitters of the central nervous system. Affected neurons generate distorted information to the brain in the form of pain. The mixed type concerns cancer-related pain; in this case, several factors act simultaneously.
– PRM in Pain Therapy is a complete method with excellent therapeutic results of administering drugs to acupuncture points to control inflammatory (nociceptive) pain, as well as neuropathic and mixed types of pain.
Keywords: pain, pain associated with the inflammatory process, Physiological Regulatory medicine, acupuncture points, homeopathy, interleukins, PNEI
Physiological Regulatory Medicine (PRM) is the latest achievement of integration between traditional and homeopathic medicine. In PRM, the principles of classical homeopathy are combined with an innovative therapeutic concept - with the aim of restoring the physiological state through the action of molecules (hormones, neuropeptides, interleukins and growth factors) in homeopathic dilutions, which correspond to physiological concentrations of the biological environment.
This method is based on advanced data from the fields of homeopathy, homotoxicology, psycho-neuro-endocrine-immune (PNEI) direction and nutrition.
In phylogenetic development macrophages are producers of neurotransmitters, neuropeptides, hormones and cytokines; on the other hand, neurons (with the direction of receptors) also have the ability to produce these substances, as well as growth factors.
The anatomical and functional integration of these systems completes the macrosystem picture. Psycho-neuro-endocrine immunology is a new field of study that is rapidly developing and is gaining increasing interest among research groups, physicians and medical school representatives (workshop at Loyola University Chicago - Stritch School of Medicine, November 2007; symposium at Miller School of Medicine at University of Miami, June 2008), - with the discovery of numerous molecular phenomena, many physiological and pathological conditions, the mechanisms of action of which were unknown, have been explained.
It follows that the CNS is connected to neurotransmitters, neuropeptides, hormones and cytokines, which together form the Psycho-Neuro-Endocrine-Immune (PNEI) axis.
PRM is guided by the innovative concept of combining the basic practices of homeopathic and allopathic medicine, integrating elements of acupuncture and mesotherapy (among others) with modern psychology and thus achieving superior therapeutic results.
- Therefore, the effect of acupuncture pain treatment can be improved by using these aspects.
On the other hand, pain and tolerance are two sides of the same coin. When injured, a person experiences unpleasant sensations that reflect individual psychophysical and exogenous factors. The duration of pain is a very important factor in determining the psychophysical effects: acute pain occurs quickly and is often associated with specific causes. However, if the development of pain does not correspond to the prognosis for a typical acute illness or the recovery period, the pain becomes chronic. Chronic pain, on the other hand, causes physical and psychological distress in the patient, accompanying him/her (almost always) for the rest of his/her life.
- Physiological
- Nociceptive or associated with inflammation
- Neuropathic
- Mixed
- PHYSIOLOGICAL PAIN
At the physiological level, pain is acute and of great importance for the preservation of human life. While loss of vision or hearing can be compensated for, insensitivity to pain poses a deadly threat to humans and animals.
- NOCICEPTIVE OR INFLAMMATION ASSOCIATED PAIN
At the nociceptive level, peripheral pain can be somatic or internal; it relates to inflammation.
One pain relief strategy targets the peripheral level—nociceptors—using drugs to inhibit the synthesis of proinflammatory and pain prostaglandins. Nonsteroidal anti-inflammatory drugs (NSAIDs) are used as first-line agents to control mild inflammation-related pain, but with often severe side effects.
Inflammation as a physiological process occurs in response to tissue damage.
Damage to cells causes their membranes to release phospholipids (PL), which are converted into arachidonic acid (AA) through the A2 phospholipase reaction. The AA in the cyclooxygenase (COX) enzyme generates prostagrandins (PG), which are responsible for vasodilation, increased blood circulation, inflammatory secretions and sensitization of nerve endings (nociceptors), causing the sensation of pain and other signs of inflammation (heat, redness, swelling). Cytoprotective PGs are involved in the protection of the gastrointestinal mucosa by suppressing acid production and enhancing the secretion of mucus and bicarbonate, mechanisms for maintaining mucosal integrity and the level of glomerular filtration.
In 1971, the mechanism of action of nonsteroidal anti-inflammatory substances (NSAIDs) was discovered - through suppressionCOX, where AA is the substrate.
In 1972, 2 isoforms of the COX enzyme (COX1 and COX2) were discovered.
Most cells in the body contain COX-1 (constitutive); inflamed tissues are characterized by the presence of COX-2 (inducible) in response to the presence of pro-inflammatory interleukins. These discoveries have led to the hypothesis that selective COX-2 inhibitory NSAIDs may provide an anti-inflammatory analgesic effect with less side effects and interference with COX-1. As a result, typical NSAID-associated gastrointestinal, renal, and platelet dysfunctions are less common; COX-2 inhibition is expressed by reducing the production of PG in inflamed tissues - to obtain the desired therapeutic effect. This concept marked the beginning of research in the field of selective COX-2 inhibitors.
- NEUROPATHIC PAIN
Neuropathic pain is intense and centrally mediated, manifesting itself as a result of damage, compression or dysfunction of the peripheral nerves of the central nervous system; These are disorders of the neurotransmitters of the central nervous system. Affected neurons generate incorrect signals, which the brain interprets as pain.
The reason for this may be:
diabetic neuropathy; infection: the effect of herpes zoster on the central nervous system or compression of the peripheral nerve: sciatica; multiple sclerosis; surgical disorder; Phantom pain.
Therapy is aimed at using pregabalin, gabapentin, amitriptyline and other agents for modulating pain, especially associated with diabetic neuropathy and fibromyalgia. In this case, the possibility of severe side effects should be taken into account - in contrast to the Physiological Regulatory Medicine method, where such a risk does not exist.
Ultimately, the irritation from nociceptive pain is proportional to the intensity of the stimulus; In neuropathic pain, a small stimulus can provoke a higher intensity.
This type of pain is excellently modulated by levels of glutamate (the most excitatory neurotransmitter) and the highly analgesic beta-endorphins.
- MIXED TYPE OF PAIN
This group includes several factors simultaneously; The most common pain associated with cancer is pain, which is especially difficult to control. In this case, it is suggested to use painkillers alone or in combination with opiates. PRM may also have a positive effect; containing beta-endorphin(potent endogenous analgesic in physiological concentrations) drugs help avoid side effects of other procedures for such patients.
INNOVATIVE DEVELOPMENTS IN PAIN CONTROL
Based on scientific achievements, we have developed 10 Injectables to Control Pain(Guna-Neck, Guna-Thoracic, Guna-Lumbar, Guna-Shoulder, Guna-Hip, Guna-Handfoot, Guna-Ischial, Guna-Polyarthritis, Guna-Muscle, Guna-Neural, 2.0 ml each (Guna S.p.a. - Milan, Italy)). They are prepared in homeopathic form with the addition of new active ingredients such as anti-pro-inflammatory interleukins (Anti IL-1α, Anti IL-1ß) and beta-endorphin, in concentrations similar to those found in tissues. 9 drugs (except GUNA– MUSCLE) contain beta-endorphin, 8 – contain anti-pro-inflammatory interleukins (Anti IL-1α, Anti IL-1ß) (except GUNA– MUSCLE And GUNA– NEURAL). Thus, the drugs are able to modulate nociceptive, neuropathic and mixed pain without undesirable effects. Using acupuncture points, a well-known and effective method of pain relief, involves various neurophysiological mechanisms.
Finally, by referring to the recommendations for the use of acupuncture points in pain therapy and determining the most suitable drug according to the Guna Method, we obtain an excellent therapeutic technique that uses various physiological mechanisms to modulate pain. Therapeutic recommendations include intradermal (s/c) injections of 0.5 ml into each acupuncture point of the affected area, using the technique of homeopathic mesotherapy (homeosynia) with the following advantages: according to our own experience and the experience of many colleagues over the past 3 years, the method has no contraindications, does not cause focal reactions or short-/long-term side effects, does not affect other drugs, interacting with other PRMs or homotoxicological agents that can be used in combination. To control pain, ampoule PRM drugs can also be used intramuscularly and orally (in case of a drug-allergic reaction).
– This article may be useful not only for determining the origin of pain, but also for controlling it using an innovative and very effective method.
Based on pathophysiological mechanisms, it has been proposed to distinguish between nociceptive and neuropathic pain.
Nociceptive pain occurs when a tissue-damaging stimulus acts on peripheral pain receptors. The causes of this pain can be a variety of traumatic, infectious, dysmetabolic and other injuries (carcinomatosis, metastases, retroperitoneal neoplasms), causing activation of peripheral pain receptors.
Nociceptive pain- This is most often acute pain, with all its inherent characteristics. As a rule, the painful stimulus is obvious, the pain is usually well localized and is easily described by patients. However, visceral pain, less clearly localized and described, as well as referred pain are also classified as nociceptive. The appearance of nociceptive pain as a result of a new injury or disease is usually familiar to the patient and is described by him in the context of previous pain sensations. Characteristic of this type of pain is their rapid regression after the cessation of the damaging factor and a short course of treatment with adequate painkillers. It should, however, be emphasized that long-term peripheral irritation can lead to dysfunction of the central nociceptive and antinociceptive systems at the spinal and cerebral levels, which necessitates the need for the fastest and most effective elimination of peripheral pain.
Pain that occurs as a result of damage or changes in the somatosensory (peripheral and (or) central) nervous system is classified as neuropathic. Despite some, in our opinion, inadequacy of the term “neuropathic”, it should be emphasized that we are talking about pain that can occur when there is a violation not only in the peripheral sensory nerves (for example, with neuropathies), but also with pathology of the somatosensory systems in all its levels from the peripheral nerve to the cerebral cortex.
Below is a short list of causes of neuropathic pain depending on the level of involvement. Among the above diseases, it should be noted the forms for which pain is the most characteristic and occurs more often. These are trigeminal and postherpetic neuralgia, diabetic and alcoholic polyneuropathy, tunnel syndromes, syringobulbia.
“Pain syndromes in neurological practice”, A.M.Vein
The possibility of habituation (habituation) with repeated stimuli in epicritic pain and the phenomenon of increased pain (sensitization) in protopathic pain suggest a different participation of two afferent nociceptive systems in the formation of acute and chronic pain. Different emotional-affective and somato-vegetative accompaniment for these types of pain also indicates a different participation of pain afferentation systems in the formation of acute and chronic pain:...
A fundamental aspect in the problem of pain is its division into two types: acute and chronic. Acute pain 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, skeletal muscles and internal organs, dysfunction of the smooth...
Pain Receptors and Peripheral Nerves Traditionally, there are two main theories of pain perception. According to the first, put forward by M. Frey, the skin contains pain receptors from which specific afferent pathways to the brain begin. It was shown that when human skin was irritated through metal electrodes, the touch of which was not even felt, “points” were identified, the threshold stimulation of which was perceived as sharp, unbearable pain. Second...
There are several hypotheses. According to one of them, pathological impulses from internal organs, entering the posterior horn of the spinal cord, excite the pain sensitivity conductors of the corresponding dermatomes, where pain spreads. According to another hypothesis, afferentation from visceral tissues en route to the spinal cord switches to the cutaneous branch and antidromically causes an increase in the sensitivity of cutaneous pain receptors, which...
Various types of pain are associated with the activation of afferent fibers of a certain caliber: the so-called primary - short-latency, well-localized and qualitatively determined pain and secondary - long-latency, poorly localized, painful, dull pain. It has been experimentally shown that “primary” pain is associated with afferent impulses in A-delta fibers, and “secondary” pain is associated with C-fibers. However, A-delta and C-fibers are not exclusively...
Nociceptive pain perception system. It has a receptor, conductor section and a central representation. Mediator this system - substance R.
Antinociceptive system- a system of pain relief in the body, which is carried out through the action of endorphins and enkephalins (opioid peptides) on opioid receptors of various structures of the central nervous system: periaqueductal gray matter, raphe nuclei of the reticular formation of the midbrain, hypothalamus, thalamus, somatosensory cortex.
Characteristics of the nociceptive system.
Peripheral section of the pain analyzer.
It is represented by pain receptors, which, according to the proposal of Charles Sherlington, are called nociceptors (from the Latin word “nocere” - to destroy).
These are high-threshold receptors that respond to irritating factors. According to the mechanism of excitation, nociceptors are divided into mechanonociceptors And chemonocyceptors.
Mechanoreceptors located mainly in the skin, fascia, joint capsules and mucous membranes of the digestive tract. These are free nerve endings of group A Δ (delta; conduction speed 4 – 30 m/s). They respond to deforming influences that occur when tissues are stretched or compressed. Most of them adapt well.
Chemoreceptors are also located on the skin and mucous membranes of internal organs, in the walls of small arteries. They are represented by free nerve endings of group C with a conduction speed of 0.4 – 2 m/s. They react to chemicals and influences that create O 2 deficiency in tissues and disrupt the oxidation process (i.e., algogens).
Such substances include:
1) tissue algogens– serotonin, histamine, ACh and others are formed during the destruction of mast cells of connective tissue.
2) plasma algogens: bradykinin, prostaglandins. They act as modulators, increasing the sensitivity of chemonocyceptors.
3) Tachykinins under damaging influences, they are released from nerve endings (substance P). They act locally on membrane receptors of the same nerve ending.
Wiring department.
Ineuron- a body in the sensory ganglion of the corresponding nerves innervating certain parts of the body.
IIneuron- in the posterior horns of the spinal cord. Further painful information is carried out in two ways: specific(lemniscus) and nonspecific(extralemniscal).
Specific way starts from interneurons of the spinal cord. As part of the spinothalamic tract, impulses arrive at specific nuclei of the thalamus (III neuron), the axons of the III neuron reach the cortex.
Non-specific path carries information from the interneuron to various brain structures. There are three main tracts, neospinothalamic, spinothalamic and spinomesencephalic. Excitation along these tracts enters the nonspecific nuclei of the thalamus, and from there to all parts of the cerebral cortex.
Cortical department.
Specific way ends in the somatosensory cortex.
This is where the formation takes place. acute, precisely localized pain. In addition, due to connections with the motor cortex, motor acts are carried out when exposed to painful stimuli, awareness and development of behavior programs under pain occurs.
Non-specific path projects to various areas of the cortex. Of particular importance is the projection to the orbitofrontal cortex, which is involved in the organization of the emotional and autonomic components of pain.
Characteristics of the antinociceptive system.
The function of the antinociceptive system is to control the activity of the nociceptive system and prevent its overexcitation. The restrictive function is manifested by an increase in the inhibitory influence of the antinociceptive system on the nociceptive system in response to a painful stimulus of increasing strength.
First level represented by a complex of structures of the mid, medulla oblongata and spinal cord, which include periaqueductal gray matter, raphe nuclei and reticular formation, as well as gelatinous substance of the spinal cord.
The structures of this level are combined into a morphofunctional “system of descending inhibitory control.” Mediators are serotonin and opioids.
Second level presented hypothalamus, which:
1) has a descending inhibitory effect on the nociceptive structures of the spinal cord;
2) activates the “descending inhibitory control” system, i.e. the first level of the antinociceptive system;
3) inhibits thalamic nociceptive neurons. Mediators at this level are catecholamines, adrenergic substances and opioids.
Third level is the cerebral cortex, namely the II somatotropic zone. This level plays a leading role in shaping the activity of other levels of the antinociceptive system and the formation of adequate reactions to damaging factors.
The mechanism of activity of the antinociceptive system.
The antinociceptive system exerts its effect through:
1) endogenous opioid substances: endorphins, enkephalins, and dynorphins. These substances bind to opioid receptors found in many tissues of the body, especially in the central nervous system.
2) The mechanism of regulation of pain sensitivity also involves non-opioid peptides: neurotensin, angiotensin II, calcitonin, bombesin, cholecystokinin, which also have an inhibitory effect on the conduction of pain impulses.
3) Non-peptide substances also participate in the relief of certain types of pain: serotonin, catecholamines.
In the activity of the antinociceptive system, several mechanisms are distinguished, differing from each other in duration of action and neurochemical nature.
Urgent mechanism– activated directly by the action of a painful stimulus and carried out with the participation of structures of descending inhibitory control, Carried out by serotonin, opioids, adrenergic substances.
This mechanism provides competitive analgesia to a weaker stimulus if a stronger one is simultaneously applied to another receptive field.
Short-acting mechanism activated by short-term exposure to pain factors on the body. The center is in the hypothalamus (ventromedial nucleus) and the mechanism is adrenergic.
His role:
1) limits the ascending nociceptive flow at the level of the spinal cord and supraspinal level;
2) provides analgesia when the action of nociceptive and stress factors is combined.
Long acting mechanism is activated by prolonged exposure to nociogenic factors on the body. The center is the lateral and supraoptic nuclei of the hypothalamus. The mechanism is opioid. Acts through descending inhibitory control structures. Has an aftereffect.
Functions:
1) limitation of the ascending nociceptive flow at all levels of the nociceptive system;
2) regulation of the activity of descending control structures;
3) ensures the selection of nociceptive information from the general flow of afferent signals, their evaluation and emotional coloring.
Tonic mechanism maintains constant activity of the antinociceptive system. Tonic control centers are located in the orbital and frontal areas of the cerebral cortex. Neurochemical mechanism – opioid and peptidergic substances
Control of motor functions at the level of the nerve center (importance of muscle spindle stretch receptors, Golgi receptors, reciprocal functioning of neurons)
Characteristics of types of energy balance
Types of energy balance.
I A healthy adult has energy balance: energy input = energy consumption. At the same time, body weight remains constant and high performance is maintained.
II Positive energy balance.
Energy intake from food exceeds expenditure. Leads to excess weight. Normally, subcutaneous fat in men is 14–18%, and in women it is 18–22%. With a positive energy balance, this value increases to 50% of body weight.
Reasons for the positive energybalance:
1) heredity(manifests itself in increased lithogenesis, adipocytes are resistant to the action of lipolytic factors);
2) behavior– excess nutrition;
3) metabolic diseases may be related:
a) with damage to the hypothalamic metabolic regulation center (hypothalamic obesity).
b) with damage to the frontal and temporal lobes.
Positive energy balance is a health risk factor.
III Negative energy balance. More energy is expended than is supplied.
Causes:
a) malnutrition;
b) a consequence of conscious fasting;
c) metabolic diseases.
Consequence of weight loss.
Methods for determining volumetric and linear blood flow velocity
Volumetric blood flow velocity.
This is the volume of blood flowing through a cross-section of vessels of a given type per unit time. Q = P 1 – P 2 / R.
P 1 and P 2 – pressure at the beginning and end of the vessel. R – resistance to blood flow.
The volume of blood flowing in 1 minute through the aorta, all arteries, arterioles, capillaries, or through the entire venous system of both the large and small circles is the same. R – total peripheral resistance. This is the total resistance of all parallel vascular networks of the systemic circulation. R = ∆ P / Q
According to the laws of hydrodynamics, resistance to blood flow depends on the length and radius of the vessel, and on the viscosity of the blood. These relationships are described by Poiseuille's formula:
R= 8 ·l· γ
l – Length of the vessel. r - Radius of the vessel. γ – blood viscosity. π – ratio of circumference to diameter
In relation to the cardiovascular system, the most variable values of r and γ viscosity are associated with the presence of substances in the blood, the nature of the blood flow - turbulent or laminar
Linear velocity of blood flow.
This is the path traveled by a particle of blood per unit time. Y = Q / π r 2
With a constant volume of blood flowing through any general cross section of the vascular system, the linear speed of blood flow should be unequal. It depends on the width of the vascular bed. Y = S/t
In practical medicine, the time of complete blood circulation is measured: with 70–80 contractions, the circulation time is 20–23 seconds. The substance is injected into a vein and a reaction is waited for.
Ticket No. 41
Classification of needs. Classification of reactions that ensure behavior. Their characteristics .
Processes that ensure a behavioral act.
Behavior refers to all activities of an organism in the environment. Behavior is aimed at satisfying needs. Needs are formed as a result of changes in the internal environment or are associated with living conditions, including social living conditions.
Depending on the reasons causing the needs, they can be divided into 3 groups.
Classification of needs.
1) Biological or vital. Associated with the need to ensure the existence of the body (these are nutritional, sexual, defensive needs, etc.).
2) Cognitive or psycho-research.
Appear in the form of curiosity, curiosity. In adults, these reasons are the driving force behind research activity.
3) Social needs. Associated with life in society, with the values of this society. They manifest themselves in the form of a need to have certain living conditions, to occupy a certain position in society, to play a certain role, to receive services of a certain level, etc. A type of social need is the thirst for power, money, since this is often a condition for achieving other social needs.
Various needs are satisfied with the help of innate or acquired behavioral programs.
One and the same behavioral reaction is of an individual nature, associated with the individual typological characteristics of the subject.
Characteristics of reactions that ensure behavior.
They are divided into 2 groups: congenital and acquired
Congenital: unconditioned reflex, reactions programmed by nerve centers: instinct, imprinting, orientation reflex, motivation
Acquired: conditioned reflex
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 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. 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, 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 that is inadequate to the cause and pathogenesis of the 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.
Determining its pathogenesis is important for the successful treatment of pain. 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 (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.
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, irritates an intervertebral herniation of a spinal nerve (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. 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 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 potassium channel blockers is justified.
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 through 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).
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 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. The presented drugs have different points of application. 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 centrally acting muscle relaxant. 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, 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 by stabilizing the resting membrane potential.
The first representative of this class of drugs is flupirtine (Katadolon), which has a wide range of valuable pharmacological properties that distinguish it from other painkillers.
The following chapters provide detailed information about the pharmacological properties and mechanism of action of Katadolon, present the results of studies of its effectiveness and safety, describe the experience of using the drug in different countries of the world, and provide recommendations for the use of Katadolon for various pain syndromes.
