Visceral pain

Previously, it was assumed that the internal organs do not have pain sensitivity. The basis for such a judgment was the testimony of the experimenters and partly of the surgeons that the irritation of these organs does not cause a feeling of pain. However, medical practice shows that the most persistent and painful pain syndromes occur precisely in the pathology of internal organs - the intestine, stomach, heart, etc. At present, these contradictions are partially resolved, since it became known that the internal organs react not so much to mechanical stimuli as to the disorders of their inherent functions: the intestine and stomach - to stretch and contract, the vessels to contract them, and the heart to respond on metabolic disorders. Predominantly sympathetic innervation of internal organs causes certain features of their pain perception (wide prevalence of pain, duration and severe emotional coloration).

Visceral pains have two principal differences from somatic: first, they have another neurological mechanism, and secondly, the visceral pain itself has a minimum of 5 differences:

1. they are not caused by irritation of internal organs without sensitive nerve endings (liver, kidneys, pulmonary parenchyma);
2. they are not always associated with visceral trauma (for example, the incision of the intestine does not cause pain, while the tension of the bladder or the mesentery of the appendix is very painful);
3. visceral pain diffuse and poorly localized;
4. they irradiate;
5. they are associated with motor or autonomic pathological reflexes (nausea, vomiting, spasm of the dorsal muscles in renal colic, etc.).

Visceral receptors with high threshold activity include sensitive nerve endings in the heart, veins, lungs, respiratory tract, esophagus, biliary tract, intestines, ureters, bladder and uterus. Modern diagnostics makes it possible to come closer to an understanding of the perception of visceral pain. In particular, the microstimulation of the thalamus in the experiment reveals its integrative role in the process of "remembering" pain and makes it possible to create a "map" of active points of the brain that perceive visceral pain. While these studies give little to develop methods for treating such nonspecific visceral pain syndromes as, for example, irritable bowel syndrome or functional intestinal dyspepsia. Such pain, lasting 7 or more days without an exact anatomical substrate, is determined in 13-40% of all urgent hospitalizations and, despite all the most modern and expensive examinations, almost a third of these patients are prescribed without a diagnosis (there is even a special term for this - "an expensive secret"). Modern computer diagnostics has improved the recognition of pathology in these patients by about 20%, but the best method of recognizing the causes of such chronic painful abdominal syndromes is early laparoscopy. Laparoscopy is combined with lavage of the abdominal cavity and peritoneal fluid intake for the study of neutrophils: if there are more than 50% among all cells, then indications for surgery arise. Thus, MEKIingesmi et al. (1996) found that 66% of the cases of unclear abdominal pain lasting more than 2 months were abdominal adhesions, which could not be diagnosed by any other methods. After laparoscopic adhesion, in most patients the pain syndrome disappeared or sharply decreased.

Treatment

Particularly relevant is the problem of visceral pain for cancer patients. More than half of the cancer patients suffer from pain of varying intensity.

As for the treatment of pain syndrome in cancer patients, the main role, as well as many years ago, is given to pharmacotherapy - non-narcotic and narcotic analgesics, applied according to a three-stage scheme: