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INFLAMMATORY DISEASES OF INTESTINES INFECTIOUS DISEASES
Acute diarrheal diseases which majority is caused by infectious damages of intestines led to death within one year of about 20 million children under 4 years in Afrin, Asia, Latin America (data for 1975). In the developed countries intestinal infections mortality is much lower, but nevertheless they are one of basic reasons of children's incidence. For designation of acute diarrheas use the term "gastroenteritis", however it does not reflect true nature of process as at diarrhea the small and large intestine, but not a stomach usually is surprised.
Etiology and epidemiology. The main causative agents of intestinal infectious diseases known now at children are listed in tab. 12-8. Approximately in 20 — 30% of cases it is not possible to establish a cause of illness. In the countries with a temperate climate in winter months of 50% of cases of intestinal infections and 80% of cases with a heavy current are caused by a rotavirus of the person. In tropics the similar picture is observed during rainy seasons. Some representatives of parvoviruses cause the heavy outbreaks of acute diarrheal diseases; in rare instances as the reason of acute colitis serves the cytomegalovirus.
About 10 — 15% of acute intestinal infections are caused by bacteria. Frequency of bacterial infections is higher in tropical countries and among the population living in bad sanitary conditions.
Table 12-8. Causative agents of intestinal infectious diseases at children
Rotavirus of the Person viruses Cytomegalovirus Other Norfolk Viruses (adenoviruses, etc. *)
Salmonellas (S. typhi, etc.)
Yersinia enterocolitica Campylobacter jejuni E. coli
B. tuberculosis of Enterotoksikogennye E. coli V. cholerae
Clostridium, perfringens the Elementary
Giardia lamblia Entamoeba histolytica Balantidium coli Helminths of the Ascarid of the Pinworm Vlasoglavy
Toksokara (visceral Larva migrans form)
Candida albicans (Monilia)
* At acute diarrheas find in children also other viruses, but their pathogenicity is not proved.
In North America from sick children most often allocate Campylobacter jejuni and various strains of salmonellas and shigellas. Rather often Yersinia enterocolitica meets (especially in East Canada and Europe). Pathogenicity some strains E possess. coli, symbiont of distal departments of a large intestine; they cause sporadic cases of acute enteritis, epidermichesky diarrhea and "diarrhea of travelers". Diseases such at children are rather rare, except for the periods of epidemics. In the countries of Asia cholera remains a topical problem.
Amoebic dysentery meets in all regions of the world, but prevails in subtropics. The lambliasis is endemic in tropical countries, but now everywhere became the reason of intestinal diseases at children. The balanthidiasis is characteristic of the countries of Latin America, in North America meets seldom. Such helminthic invasions as an ascaridosis, an enterobiosis, toksokaroz are widespread in North America. The invasions caused by Trichiuris trichiura, Necator americanus, Ancylostoma duodenale and Ancylostoma ceylonicum, meet in the countries with warm climate more often.
Mushrooms, as well as bacteria, are normal inhabitants of intestines of the person. Candida albicans can cause small limited intestinal frustration (or to become the reason for the disseminated infection at the weakened children, and also at patients with an immunodeficiency).
Pathogeny. The majority of the known pathogenic microorganisms break functions of intestines in two ways: 1) infesting a wall of intestines or 2) emitting enterotoxin in a gut cavity. Pathogenicity of the activator, apparently, substantially depends on its ability to be attached to an intestinal wall. From all enterotoxins the choleragen produced by a cholera vibrio is most studied. It adgezirutsya on a surface of an epithelium and activates system of adenylatecyclase. As a result in cells of an epithelium tsAMF collects that also chloride ion and secretions leads in turn to disturbance of absorption of sodium chloride ion; the glyukozozavisimy mechanism of absorption of sodium at the same time is not broken by a brush border. To similarly cholera enterotoxin the thermolabile enterotoxin produced E works. coli, but a mediator in the latter case is TsGMF.
The rotavirus of the person gets into an epithelium of proximal department of intestines, breaking transport of sodium and chloride ion; also absorption of glucose and the glyukozozavisimy mechanism of absorption of sodium are broken, however the maintenance of tsAMF in cells does not change. Diarrhea in this case arises not owing to the direct damaging action of a virus, and because of inability of an epithelium to regeneration. It is known of a pathogeny of the diarrhea caused by invasive bacteria much less. Some invasive salmonellas, apparently, are capable to activate the enterotoksinopodobny mechanism of injury of intestines.
Concentration of sodium and chloride ions in plasma at acute enterotoksikogenny diarrhea makes 130 — 140 mmol/l that is much higher, than at viral enteritis (30 — 50 mmol/l). Despite disturbance of transport of glucose and decrease of the activity of disaccharidases at viral enteritis, during the acute period seldom it is possible to find large amounts of sugar as not soaked up sugar decays intestinal microflora in Calais.
Not only immunological protection, but also effective intestinal mechanisms of self-cleaning participates in fight against undesirable flora. Diarrhea causes washing away of infectious agents, and exfoliating and updating of an epithelium allow to get rid of the microbes which got into enterocytes. Thanks to it at intestinal infections usually there is a self-healing. However the reinfitsirovaniye, high pathogenicity of the activator, and also disturbance of protective mechanisms of the owner can lead to process synchronization.
Clinical manifestations. In the countries of North America intestinal infections in most cases proceed sharply and come to an end with self-healing. Diarrhea arises suddenly, is followed by vomiting and subfebrile fever. In hard cases fecal masses so liquid that they can be taken for urine. The child is excited and cries, as at pain. Vomiting and fever disappear quickly enough, and strong ponosa proceed 3 — 4 days and during the next 4 — 5 days gradually stop. At inspection of the child loud rumbling of intestines and its swelling is defined. Manual rectal research can stimulate emission of the accumulated contents of intestines and thus reveal not suspected serious condition. As a rule, the clinical picture does not allow to differentiate bacterial and virus damages (see tab. 10-16). The correct assumption can be made if contact of the child with the patient at which the activator is revealed is come; blood or pus in fecal masses indicates an invasive bacterial or amoebic infection. It is necessary to estimate urgently a condition of a water salt metabolism and acid-base equilibrium as shock, dehydration, disturbance of acid-base and electrolytic balance can lead to sudden death of the patient. The chronic diarrhea caused by Yersinia enterocolitica is followed by pains in paraumbilical area, a muscle tension in the right lower quadrant of a stomach, and also a knotty erythema and arthritis. Campylobacter jejuni can cause chronic bloody ponosa with heavy pristupoobrazny pains in the lower half of a stomach.
Treatment see in the corresponding chapter.