What causes acute gastrointestinal diseases?

Predisposing factors to the development of acute gastrointestinal diseases

I group. Anatomico-physiological features of the gastrointestinal tract

The stomach in the infant is functionally immature. The main part of the stomach, in the mucous membrane of which pepsin and hydrochloric acid are produced, is insufficiently developed, the pH of the gastric contents does not drop below 4.0 and only by the year is 1.5-2.0. Low enzymatic activity of the stomach allows the child to digest only ideally suitable for quality and quantity of food, otherwise digestive disorders develop, which leads to gastrointestinal dysfunction. Low bactericidal properties of gastric contents facilitate the development of intestinal infections.

Intestines. The main biological role of the cells of the intestinal mucosa is transport of the plastic and energy ingredients of food necessary for the body. Enterocytes synthesize a large number of enzymes - lactase, invertase, maltase, esterases, ATPase, dipeptidase and others. It is a glycocalyx that covers microvilli and, together with enzymes bound to the microvilli membrane, plays the role of an "enzyme filter", through which intense hydrolysis and absorption take place. Inadequate nutrition or infection of the gastrointestinal tract in young children develops a syndrome of "sheared" villi, which causes the violation of hydrolysis and absorption. In addition, cells of the intestinal mucosa synthesize biologically active substances - serotonin, triglycerides, glycogen, some polypeptides. The mucous membrane of the gastrointestinal tract is a powerful organ of transport of water and electrolytes. Through the gastrointestinal tract, excretion of urea, drugs, endogenous poisons occurs, etc. The violation of the latter functions in acute gastrointestinal diseases in young children leads to the development of water-electrolyte disorders and endogenous intoxication.

Blood circulation in the digestive tract is provided by a powerful vascular network. The total surface of only the capillaries of the intestine is 10 times greater than the total surface of the capillaries of the entire skeletal musculature. The presence of a variety of anatomical shunts, an abundance of pores in the venous part of the capillaries and other features of the circulation of the gastrointestinal tract provide a full absorption, and on the other hand, facilitate the occurrence of edema. And with swelling of the interstitial space of the intestinal mucosa, there is always diarrhea.

At the same time, the intestine is one of the most sensitive organs to oxygen starvation. It is established that at the slightest oxygen deficiency the absorption of glucose, amino acids and fats decreases. This explains the appearance of digestive disorders in the defeat of systems responsible for providing tissues with oxygen, respiratory and cardiovascular.

It has been established that circulatory disturbances in the intestine lead to similar disorders in other organs, for example, in the lungs, vasospasm may develop and even atelectasis may occur.

Group II. Character of feeding

The risk of getting sick with artificial feeding is 2.5-3 times higher than in the case of natural feeding, and the mortality rate from OZHKZ for artificial feeding is 25 times higher. With mixed and artificial feeding, errors in cooking technology are most often allowed, conditions for its microbial contamination are created. Almost half of the children transferred to artificial feeding, during the first two months after changing the nature of food, suffer from acute gastrointestinal diseases.

In the same group of predisposing factors, it is possible to classify situations when overstated requirements are imposed on enzymatic systems of the digestive tract - overfeeding, quantitative and qualitative, violation of the principle of gradual introduction of new products, disruption of diet, inadequate fluid administration, etc.

III group. State of reactivity

Features of the immune system at an early age:

1. Imperfection of immune systems.
2. Low titer of antibodies to various microorganisms.
3. The incompleteness of phagocytosis.

Particularly vulnerable are preterm infants with a low body weight.

Racitis and dystrophy predispose to acute gastrointestinal diseases. These children are not only damaged protective mechanisms, but also systems regulating water-salt, carbohydrate, protein, fat metabolism, there are significant changes in the digestive, circulatory, CNS.

Frequent acute gastrointestinal diseases are noted in children with immunodeficiency and conditions (primary and secondary), allergies, dysbacteriosis.

Causes and pathogenesis of acute gastrointestinal diseases

Parenteral dyspepsia is associated with acute diseases outside the gastrointestinal tract (pathology of the respiratory, cardiovascular, urinary and other systems), when into the gastrointestinal tract is affected by intoxication, hypoxia, circulatory disorders, changes in the CNS and VNS, motor disorders and intestinal dysfunction.

Dyskinesia (spasm, atony) of various parts of the gastrointestinal tract is usually a consequence of a disturbance in the regulation of muscle tone in the pathology of the nervous system in children, especially with perinatal encephalopathy.

The spectrum of causative agents of intestinal infections is wide - it is a bacterial flora, fungi, viruses, recently it has been proved important for the development of acute gastrointestinal diseases1 of opportunistic flora.

For children of the first year of life, the etiological factors for the frequency of detection in intestinal infections are distributed as follows:

1. rotavirus;
2. salmonella;
3. enteropathogenic intestinal rods;
4. proteus, klebsiella, cytobacter, enterobacter, pseudomonas;
5. shigella.

After a year:

• shigella;
• salmonella;
• enteropathogenic intestinal rods; 4) rotavirus;
• Campylobacteria.

[1], [2], [3], [4], [5], [6]

Pathogenesis of acute gastrointestinal diseases

The triggering mechanism is the decomposition products of unsweetened food ingredients (histamine-like substances, biogenic amines) with dyspepsia or microbial toxins in intestinal infections. They act on the cells of the mucosa, intestines, disrupt their basic functions (transport, synthesis, excretion), the activity of a number of enzymes is inhibited, "sheared villi" are formed, the process of parietal digestion is disrupted. Toxins lead to denaturation of cell membrane proteins, which increases the permeability of the cell barrier. This facilitates the penetration of toxins into the interior of the intestinal wall and biologically active substances formed in the lumen of the intestine. They have a strong effect on microcirculation, initially local, and then at the level of the whole organism. Toxins increase the permeability and fragility of capillaries, stagnation occurs, submucosal hemorrhage. Due to the occurrence of ischemia, oxidative processes in tissues are disrupted. The result of this is the accumulation of incomplete combustion products, lactic acid in the flowing blood, which leads to the development of metabolic acidosis. Similar changes in microcirculation occur in the liver. They lead to a violation of its functions, and above all detoxification, barrier. Toxins pass through this barrier and flood the entire body - there is toxemia.

As a result of stagnation of blood and increase in the permeability of blood vessels in the microcirculation system of the intestine, water, some mineral salts and plasma albumins begin to seep from the vascular bed into the intercellular space, and then into the lumen of the intestine. This is the origin of the stool in children with intestinal toxicosis, which explains the frequent watery stool, almost without feces, in children not receiving food.

Because of water loss, dehydration of the body occurs due to circulatory, extracellular fluid, there are changes in the cardiovascular system, hemodynamics is disrupted.

The organism as it were "looking for water" - there is a spasm of the vessels of the skin, muscles - the so-called "prey of the periphery", water is extracted from the interstitial and intracellular space and "water" is extracted from the outside - thirst, increased water reabsorption in the kidneys, diuresis decreases. But due to toxemia and a decrease in the volume of circulating blood, the kidneys begin to suffer, which aggravates acidosis. Compensation of acidosis begins to be carried out by the lungs, acidotic breathing appears.

Under the influence of toxemia, hypoxia, acidosis, the function of the central nervous system suffers, the behavior of the child is sharply disturbed. A hypovolemic shock may occur.

Classification of gastrointestinal diseases of young children, proposed by GN Speranskii.

1. Diseases of functional origin.

• Simple indigestion.
• Toxic dyspepsia.
• Parenteral indigestion (as an independent disease is not registered).
• Pylorospasm.
• Atony of various parts of the gastrointestinal tract.
• Spastic constipation.

2. Diseases of infectious origin.

• Dysentery bacterial.
• Dysentery amoeba (amoebiasis).
• Salmonellosis.
• Intestinal coli-infection.
• Intestinal form of staphylococcal, enterococcal, fungal infections.
• Viral diarrhea.
• Intestinal infection of unknown etiology. 3. Malformations of the gastrointestinal tract.
• Pylorosthenosis, megaduodenum, megacolon.
• Atresia (esophagus, intestine, anus).
• Other vices.

The acute course is characteristic for various variants of dyspepsia of a functional origin and for GI diseases of an infectious origin.

Currently, the emergence of acute gastrointestinal diseases infectious factor is the main place.