Medical expert of the article
New publications
Pain
Last reviewed: 23.04.2024
All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
Pain is an unpleasant sensation and emotional experience associated with actual and potential tissue damage or a condition described by the words of such a lesion.
The phenomenon of pain is not limited solely to organic or functional disorders in the place of its localization, pain also affects the activity of the organism as an individual. Over the years, researchers have described an uncountable number of unfavorable physiological and psychological consequences of not lightened pain.
The physiological consequences of untreated pain of any localization can include everything from deterioration of the function of the gastrointestinal tract and the respiratory system to the enhancement of metabolic processes, increased growth of tumors and metastases, decreased immunity and prolonged healing, insomnia, increased blood clotting, loss of appetite, and disability reduction.
The psychological consequences of pain can be manifested in the form of anger, irritability, feelings of fear and anxiety, resentment, decline in spirit, depression, depression, solitude, loss of interest in life, reduced ability to fulfill family responsibilities, reduce sexual activity, which leads to family conflicts and even to a request for euthanasia. Psychological and emotional effects often affect the patient's subjective reaction, exaggeration or minimizing the significance of pain. In addition, the degree of self-control of pain and illness by the patient, the degree of psychosocial isolation, the quality of social support, and, finally, the patient's knowledge of the causes of pain and its consequences may play a role in the severity of the psychological consequences of pain. The doctor almost always has to deal with evolved manifestations of pain - emotions and painful behavior. This means that the effectiveness of diagnosis and treatment is determined not only by the ability to detect etiopathogenetic mechanisms of the somatic state, manifested or accompanied by pain, but also the ability to see behind these manifestations the problem of limiting the patient's habitual life.
Causes of pain
A considerable number of works, including monographs, have been devoted to the study of the causes and pathogenesis of pain and pain syndromes. As a scientific phenomenon pain has been studied for more than a hundred years.
Distinguish physiological and pathological pain.
Physiological pain occurs at the time perception of pain receptors, it is characterized by a short duration and is directly dependent on the strength and duration of the damaging factor. Behavioral reaction in this case interrupts communication with the source of damage.
Pathological pain can occur both in receptors and in nerve fibers; it is associated with prolonged healing and is more destructive because of the potential threat to disruption of the normal psychological and social existence of the individual; Behavioral reaction in this case - the emergence of anxiety, depression, depression, which aggravates the somatic pathology. Examples of pathological pain: pain in the focus of inflammation, neuropathic pain, deafferentation pain, central pain. Each type of pathological pain has clinical features that allow us to recognize its causes, mechanisms and localization.
Types of pain
There are two types of pain.
The first type is acute pain caused by tissue damage, which decreases as it heals. Acute pain has a sudden onset, short duration, precise localization, appears when exposed to intense mechanical, thermal or chemical factors. It can be caused by infection, damage or surgery, lasts for several hours or days and is often accompanied by symptoms such as heart palpitations, sweating, pallor and insomnia.
The second type - chronic pain develops as a result of damage or inflammation of tissue or nerve fiber, it persists or repeats for months or even years after healing, does not bear a protective function and causes suffering to the patient, it is not accompanied by signs characteristic of acute pain. Unbearable chronic pain has a negative impact on the psychological, social and spiritual life of a person.
Somatic pain occurs when the skin of the body is damaged or stimulated, as well as when deeper structures are damaged - muscles, joints and bones. Bony metastases and surgical interventions are common causes of somatic pain in patients suffering from tumors. Somatic pain, as a rule, is constant and quite clearly limited; it is described as pain pulsating, gnawing, etc.
Visceral pain is caused by stretching, constriction, inflammation or other irritations of the internal organs. It is described as deep, compressive, generalized and can radiate into the skin. Visceral pain, as a rule, is constant, it is difficult for the patient to establish its localization.
Neuropathic (or deafferentation) pain occurs when nerves are damaged or irritated. It can be permanent or unstable, sometimes shooting, and is usually described as sharp, stitching, cutting, burning, or as an unpleasant sensation. In general, neuropathic pain is the most serious in comparison with other types of pain, it is more difficult to treat.
Clinically, pain can be classified as follows: nocigenic, neurogenic, psychogenic. This classification may be useful for initial therapy, however, in the future such division is impossible because of a close combination of these pains.
Nosigenic pain occurs when skin nociceptors, nociceptors of deep tissues or internal organs become irritated. Emerging in this case, the impulses follow the classical anatomical pathways, reaching the higher parts of the nervous system, are displayed by consciousness and form a sense of pain. Pain in internal organs is a result of rapid contraction, spasm or stretching of smooth muscles, since the smooth muscles themselves are insensitive to heat, cold or dissection. Pain from internal organs that have sympathetic innervation can be felt in certain areas on the surface of the body (the Zakharyin-Ged zone) - this is reflected pain. The most famous examples of such pain are pain in the right shoulder and right side of the neck with gallbladder involvement, pain in the lower back with bladder disease and, finally, pain in the left arm and left side of the chest with heart disease. The neuroanatomical basis of this phenomenon is not entirely clear. A possible explanation is that the segmental innervation of the internal organs is the same as that of the remote areas of the body surface, but this does not explain the reasons for the reflection of pain from the organ to the surface of the body. Nocigenic type of pain is therapeutically sensitive to morphine and other narcotic analgesics.
Neurogenic pain. This type of pain can be defined as pain due to damage to the peripheral or central nervous system and is not explained by nociceptor irritation. Neurogenic pain has many clinical forms. These include some lesions of the peripheral nervous system, such as postherpetic neuralgia, diabetic neuropathy, incomplete injury of the peripheral nerve, especially the median and ulnar (reflex sympathetic dystrophy), detachment of branches of the brachial plexus. Neurogenic pain due to central nervous system damage is usually due to a cerebrovascular accident - this is known by the classic name of "thalamic syndrome", although studies (Bowsher et al., 1984) show that in most cases lesions are located in areas other than the thalamus.
Psychogenic pain. The statement that pain can be of exclusively psychogenic origin is debatable. It is widely known that the patient's personality forms a painful sensation. It is strengthened in hysterical individuals, and more accurately reflects the reality in patients of a non-isteroid type. It is known that people of different ethnic groups differ in perceptions of postoperative pain. Patients of European descent experience less intense pain than American Negroes or Hispanics. They also have a low pain intensity compared to Asians, although these differences are not very significant (Faucett et al., 1994). Some people are more resistant to the development of neurogenic pain. Since this trend has the aforementioned ethnic and cultural characteristics, it seems congenital. Therefore, the prospect of research aimed at locating localization and isolating the "pain gene" is so tempting (Rappaport, 1996).
Neuropathic pain. Neuropathic (neurogenic) pain as a kind of chronic pain is caused by damage to the peripheral or central nervous system, or a disease that affects any sensitive nerves or central ganglia. Examples: lumbar pain, diabetic neuropathy, postherpetic neuralgia, post-traumatic central or thalamic pains and post-mutant phantom pain.
Neuropathic pains are usually classified based on the etiological factor causing damage to the nervous system, or based on anatomical localization of pain (trigeminal, lumbosacral, intercostal neuralgia). Neuropathic pain is characterized by a complex of negative and positive syndromes. Syndromes of prolapse are manifested by sensory deficiency in the form of complete or partial loss of sensitivity in the zone of innervation of the affected nerves. Positive symptoms are characterized by the presence of spontaneous pain in combination with dysesthesia and paresthesia.
[