Dysentery

Dysentery (shigelloses) - the infectious disease characterised by a syndrome of the general infectious intoxication and a syndrome of a lesion of a gastrointestinal tract, mainly distal part of a colon.

The dysentery is caused by the bacteria of sort Shigella including more 40 serological and biochemical differentiated variants. Shigellas well grow on usual nutrient mediums; at destruction of microbic cells the endotoxin which plays the big role in a pathogenesis of disease is excreted and causes clinical implications. Besides, Shigellas produce some kinds of ectotoxin: the cytotoxin damaging membranes of epithelial cells; the enterotoxins intensifying secretion of fluid and salts in a lumen of an intestine; the neurotoxin found in basic at the bacteria of Grigoriev-Shiga (Sh. dysenteriae a serovar 1). In modern conditions the greatest diffusion have Flexner shigella and Shigella sonnei.

Pathogenicity of Shigellas is defined by 4 major factors: ability to adhesion, an invasion, a toxin production and intracellular reproduction. It is most expressed at Grigoriev-Shiga bacteria (Sh. dysenteriae 1), a little less - at Flexner shigella and it is even less than serovar at other kinds.

The important property of Shigellas is their ability quickly to variate the sensitivity to various anti-infectives depending on frequency of their application in this or that region. In most cases medicinal fastness is transferred to Shigellas from bacteria of a gastrointestinal tract by genes of transmissible plasmids of resistance. The expressed virulence (for example, Flexner shigella 2а), presence at separate strains of transmissible medicinal fastness, especially plural, in many respects causes ability of these microorganisms to cause mass diseases in the form of the large epidemies, diseases characterised by serious flow. The lethality in the epidemic season can reach 2-7 %.

Dysentery originators, especially Shigella sonnei, differ high survival rate in an external environment. Depending on temperature-moist conditions they keep the biological properties from 3-4 days till 1-2 months, and in some cases till 3-4 months and even more. Under congenial conditions Shigellas are capable to reproduction in foodstuff (salads, Russian salads, boiled meat, forcemeat, boiled fish, milk and milk products, compotes and kissels), especially Shigella sonnei.

Epidemiology

The dysentery concerns anthroponoses with the fecal-oral mechanism of transfer of the originator, realised alimentary, water and is contact-household pathes. In the conditions of the organised collectives alimentary and water pathes have the greatest value. The becoming infected suffices for development of disease less than 100 microbic cells of Shigellas.

Contagium source at a dysentery are patients the acute and chronic form, and also bacillicarriers, persons with the subclinical form of an infection contamination which excrete Shigellas in an external environment with excrements. Most contagious patients acute, typically proceeding forms of disease. In the epidemic attitude the special danger is represented by patients and bacillicarriers from among constant workers of a food and water supply. Sick of a dysentery the disease beginnings, and sometimes and from the incubation interval extremity are infectious about. Duration of abjection of the originator patients, as a rule, does not exceed week, but can be tightened and till 2-3 weeks. A role of the convalescents sick of an acute fixing and chronic dysentery, as infection contamination sources a little above at Flexner's dysentery.

On a sensibility to a dysentery humans are rather impure. At humans with blood group A (II) clinically expressed forms of an infection contamination prevail. The greatest sensitivity to an infection contamination at persons with blood group A (II), Hp (2), Rh (-).

Pathogenesis

A major factor in a disease pathogenesis is the toxemia at the expense of entering shigellosis poisons, and also ekzo - and endotoxins of other colibacilluses, products of an inflammation and a necrosis from the struck parts of a colon. First of all the central and peripheric excitatory system, and also cardiovascular system, adrenals and digestion organs is amazed. At persons with an immunodeficiencyy and trophic insufficiency the widespread and long lesion of an intestine is characteristic.

Shigellas can be in a stomach from several o'clock about several days (in rare instances). Thus some of them already here break up, releasing an endotoxin. Having broken an acid barrier of a stomach, Shigellas get to an intestine. In a small bowel they are attached to enterocytes and excrete enterotoxin ectotoxin which causes a hypersecretion of fluid and salts in an intestine lumen. The pancreatic enzymes containing in a small bowel, for a while inactivate a hemolysin of an outer membrane of the Shigellas, providing their invasion in epithelial cells, and it protect the last. However the part of bacteria inpours into enterocytes, mainly ileal intestine, and propagates in them. Under the influence of a hemolysin phagocytal vacuoles are blasted and cytopathic changes in enterocytes educe. Shigellas activly move in a cytoplasma and pass in the next enterocytes, causing inflammatory process in a small bowel which is sustained and aggravated with action of the cytotoxic ectotoxin produced by Shigellas depressing synthesis of proteins. However intercellular diffusion of the originator to a small bowel, as a rule, quickly breaks because of killer actions of lymphocytes. The endotoxin formed as a result of destruction of Shigellas in the locuses of an initial invasion in an epithelium of a small bowel, gets to blood and causes intoxication development. At serious and extremely serious flow of disease the bacteriemia can educe.

In a colon the invasion Shigellas colonocytes arises a little bit later, but a massively. It leads to more appreciable aboriginal and resorptive action of toxins of Shigellas. The interepithelial lesion Shigellas colonocytes progresses; defects of an epithelial integument are enlarged; the cell-bound immune complexes which component is the endotoxin, are fixed in capillars of a mucosa of a colon and, breaking microcirculation, enhance its damage. Secretion by sensibilized eosinocytes and mast cells of toxic substances in a combination to circulation disturbance in a submucosal layer and cytotoxic effect of leucocytes define development of pathological process from 2nd week of disease. As a result of it the IDCS, including local (in an intestine), with the further development of clottages of mesenteric pots, and also pots of lungs and a brain educes.

Toxins of Shigellas can be fixed by tissues a CNS and amaze the vegetative nervous system centres. Besides immediate effect on a number of organs the endotoxin of Shigellas promotes development common metabolic disturbances.

At a chronic dysentery the leading part is played not by an intoxication, and progressing disturbance of a functional condition of the gastrointestinal tract, defining a clinical picture of disease.

Recover at a dysentery is usually accompanied by remission of an organism of the originator. However at insufficiency of immune system purification of an organism from the originator is tightened till 1 month and more. The reconvalescent carriage is formed, and at a part had been ill disease gets chronic flow.

After the tolerated disease or an asymptomatic infection contamination it is formed short species-specific and type-specific immunodefence. In protection of an organism against an infection contamination the basic role belongs to factors of aboriginal immunodefence (microphages, T lymphocytes, secretory IgA). Intense Enough aboriginal immunodefence is sustained only at a regular antigenic boring. For lack of antigenic influences duration of conservation specific IgAs in protective titer does not exceed 2-3 months at sonnei Dysentery and 5-6 months at Flexner's dysentery.

Symptoms and flow

The incubation interval compounds 1-7 (on the average 2-3) days, but can be reduced till 2-12 o'clock.

Excrete following forms and variants of flow of an infection contamination:

1. An acute dysentery: colitis and gastroenterocolitis variants. On gravity of flow they are sectioned on easy, moderately severe, serious and very serious; on features of flow excrete erased, subclinical and fixing.
2. A chronic dysentery: recurring and continuous.
3. The bacteriocarrier of Shigellas: reconvalescent and transitional.

The form, variant and gravity of flow of a dysentery depend on pathes and means of infestation, size of an infecting dose of Shigellas, their virulence, level of resistance and immunodefence of the macroorganism.

The basic clinical variant of disease is colitis. It prevails in cases of the dysentery caused Sh. dysenteriae and Sh. flexneri.

Disease begins acutely. In the beginning the syndrome of the general intoxication characterised by a fervescence, a fever, sense of fever, weakness, appetite depression, an adynamia, a headache, a bradycardia, depression of arterial pressure educes.

The lesion of a gastrointestinal tract shows abdominal pains, in the beginning stupid, poured on all gaste, having constant character. Then they become more acute, colicy, are localised in the inferior parts of a gaste, more often at the left. Pains usually strengthen before a defecation, there are tenesmuses and false desires.

The spastic stricture and the morbidity of a colon more expressed in the field of sigmoid part is palpatory defined. The chair becomes frequent, excrements have in the beginning fecal character, then decrease in volume, become liquid. Thus there are pathological admixings in the form of phlegm and blood streaks. In more serious cases at a defecation the small amount of phlegm with blood streaks ("a rectal spittle") is excreted only.

Easy severe dysentery

At easy disease fever is short-term, from several o'clock till 1-2 days, the body temperature, as a rule, raises to 38. Patients are disturbed by moderate abdominal pains, basically before the defecation certificate. They are localised more often in the left ileal range, but can extend on all gaste. Some patients have false desires. Excrements have fecal character, a pultaceous or semifluid consistence, frequency of defecations to 10 times a day, a phlegm and blood admixing macroscopicly is found not always and taped only at coprocytologic research.

At survey of the patient the spastic stricture and moderate morbidity of a sigmoid intestine, sometimes and other parts of a colon is defined obstruction tongue. At a proctosigmoidoscope, as a rule, find catarral, is rarer - catarral - hemorrhagic and catarral - an erosive diffusive proctosigmoiditis.

The intoxication and diarrhoeia remain within 1-3 days. The spastic stricture and morbidity of a sigmoid intestine are a little bit more longly defined. The full reparation of a mucosa of a colon comes in 2-3 weeks.

Moderately severe dysentery

Moderately severe disease is characterised by distinct signs of an intoxication and a colitis syndrome. The beginning of disease the acute. The body temperature with cold fits raises to 38-39Cdeg and keeps at this level from several o'clock to 2-4 days of Patients the general delicacy, a headache, giddiness, absence of appetite disturb.

Intestinal disorders, as a rule, join in the next 2-3 hours from the disease beginning. Patients have periodic colicy pains in the inferior part of a gaste, frequent false desires on a defecation, tenesmuses, sensation of incompleteness of the certificate of a defecation. Frequency of a chair reaches 10-20 times a day. Excrements poor, often lose fecal character and consist of one phlegm with blood streaks.

The adynamia of the patient, acrimony, pallor of a skin is objectively taped. Sphygmus frequent, small filling. Systolic arterial pressure decreases to 100 mm hg Cardiac sounds are muffled. Tongue is covered by dense white scurf, dryish. At a gaste palpation the expressed spastic stricture and sharp morbidity of sigmoid part are defined, is frequent also other parts of a colon. At a proctosigmoidoscope most typical diffusive is catarral-erosive changes with plural hemorrhages, sometimes mucosa ulcers. In a haemogram - neutrophilic a leukocytosis to 8-10o109/л, moderate alteration to the left.

The intoxication and diarrhoeia proceed from 2 till 4-5 days, the spastic stricture, infiltration and morbidity of a colon a little bit more longly remain at a palpation. The full morphological reparation of a mucosa of an intestine and normalisation of all functions of an organism come not earlier than 1-1,5 months

Serious severe dysentery

Serious flow of a colitis variant of a dysentery is characterised by very fast development of disease sharply expressed by the general toxicosis, deep disturbances of activity of cardiovascular system and bright semiology of a colitis syndrome. Disease begins extremely acutely. The body temperature with a fever quickly raises to 40Cdeg and above, patients complain of a strong headache, the sharp general delicacy, the raised chilliness, especially in extremities, giddiness at a rising from the bed, full absence of appetite. Quite often there is a nausea, vomiting, a hiccup. Simultaneously with an intoxication the expressed colitis syndrome educes. Patients are disturbed by the abdominal pains accompanied by excruciating tenesmuses and frequent desires on a defecation and an emiction. A chair more than 20 times a day, are frequent number of defecations difficultly to count ("a chair without the account"). Owing to a paresis of sphincters patients have an anus ostium from which the krovjanisto-necrotic masses which are often looking like "meat slops" are continuously excreted.

Sphygmus frequent, arterial pressure is lowered, especially diastolic. The dimensions of warm dullness are a little dilated, cardiac sounds deaf persons, the accent of I tint on a pulmonary artery is auscultated. Tongue is covered by brown scurf, dry. The colon palpation is complicated because of sharp morbidity.

At a proctosigmoidoscope in an intestine mucosa on all extent a fibrinous inflammation, the plural locuses of hemorrhages and a necrosis. After tearing away of fibrinous scurfs and necrotic masses slowly healing ulcers are formed.

In peripheric blood the leukocytosis to 12-15o109/л, the absolute and relative neutrocytosis, the expressed alteration to the left in the leukocytic formula and toxic granularity of neutrophils is observed, the ESR raises to 30 mm/ch and more. In urine find squirrels, erythrocytes.

The season of height of disease proceeds 5-10 days. Recover descends slowly, infiltration and morbidity of a colon remain till 3-4 weeks, full normalisation of a mucosa descends in 2 months and more.

Very much (extremely serious flow of a colitis variant of an acute dysentery is characterised by the subitaneous rough beginning. The body temperature with a tremendous fever quickly raises to 41Cdeg and above. The phenomena of the extremely serious general toxicosis are sharply expressed. On this background at patients even before appearance of a colitis syndrome complications can educe: the infectious-toxic shock, is rarer - an infectious-toxic encephalopathy.

Last years the sharp augmentation of quantity sick of a serious dysentery becomes perceptible. Morphological implications Flexner's dysentery are characterised by appreciable prevalence of pathological process. At 95 % along with a total lesion of a colon the lesion ileal, is rarer - a jejunum. Depending on the disease season in a colon prevail is catarral-fibrinous, fibrinozno-ulcer and hemorrhagic, phlegmonous - necrotic and widespread ulcerative forms of an inflammation. In a small bowel are found catarral - fibrinous changes more often. Are much more often diagnosed serious disbiotical disturbances in an intestine.

The cause of a gastroenterocolitis variant of an acute dysentery are, as a rule, Shigella sonnei.

For it simultaneous development of syndromes of the general toxicosis, a gastroenteritis and dehydration while colitis symptoms in the first days are expressed weakly is characteristic or are absent. Disease begins with a fever, a fervescence to 38-39Cdeg, appearances of pains in an anticardium, a nausea and repeated vomiting. After a while there is a rumble and pains on all gaste, imperative desires on a defecation. Excrements abundant, liquid, a light yellow or green coloration with slices of undigested nutrition, it is frequent with a phlegm admixing.

At objective research dehydration signs - the pointed features, the sunk down eyes, the lowered humidity of conjunctivas, dryness of mucosas of an oral cavity and a pharynx, a hiccup are taped. Sphygmus frequent, weak filling and a strain, arterial pressure is a little lowered, cardiac sounds are relaxed. At a gaste palpation the rasping loud rumble, a capotement on a colon course becomes perceptible. For 2-3rd day of disease there are false desires, tenesmuses, in a feces a phlegm admixing, sometimes bloods. At survey the spastic stricture and moderate morbidity of a sigmoid intestine are taped, at a proctosigmoidoscope - a catarral or is catarral-erosive proctosigmoiditis.

Gravity of disease at a gastroenterocolitis variant of a dysentery basically depends on degree of dehydration of an organism. Easy disease is not accompanied by dehydration symptoms. At moderately severe flow there are signs of dehydration of I degree. At serious disease dehydration II-III of degree with loss by an organism of 4-10 % of fluid from body mass educes.

The acute dysentery with the erased flow represents very easy form of disease with the minimum subjective implications of disease. At careful clinical inspection the spastic stricture and morbidity of sigmoid part of a colon are defined. rectoromanoscopically the catarral proctosigmoiditis is observed. At microscopy of excrements a lot of phlegm and the enlarged quantity of leucocytes (more than 15 in sight) is taped.

The subclinical form of an acute dysentery is diagnosed on the basis of abjection of Shigellas from excrements in a combination to revealing of increase of a caption anti shigellas antibodies in serological tests. Clinical implications of disease in these cases are absent.

It is necessary to consider flow of an acute dysentery fixing when symptoms of disease and abjection of Shigellas remain more than 2 weeks at the easy form of disease, 3 weeks at moderately severe and 4 weeks at the serious form. The immunodeficient condition of the diseased, trophic insufficiency or inadequate etiopathogenetic therapy can be the causes of it. Fixing serious forms of an acute dysentery (especially Flexner) proceed or are accompanied, as a rule, by the general attrition with depression of immunobiological reactance, with a serious fibrinopurulent lesion of all colon and distal part of a small bowel. Presence thus deep ulcers, a hectic fever allows the establishment to assume apposition secondary, including, a mephitic gangrene.

The diagnosis of a chronic dysentery is established in case disease proceeds more than 3 months

At recurrent flow of a chronic dysentery of an exacerbation alternate with the seasons of full clinical well-being which can proceed from several weeks to 2-3 months It meets much more often the continuous. At relapse of the phenomenon of an intoxication and expression of dysfunction of an intestine are usually less expressed, than at primary disease. The state of health of the patient essential is not broken, the body temperature normal, is rarer subfebrile, frequency of a chair is insignificant (usually 3-5 times a day), tenesmuses and blood in a chair, as a rule, are absent.

At continuous disease the remission seasons are absent, steady advance of pathological process and an aggravation of symptoms of the patient is observed. Unsharply expressed general intoxication, development of deep inflammatory and trophic changes in a colon, total involving in pathological process of organs of digestion, an intestinal dysbacteriosis is characteristic. The unstable, semiissued or pultaceous chair (sometimes with a phlegm and pus admixing, was rarely bloods), the signs specifying in a lesion of a stomach and a small bowel (sense of gravity in epigastric range, an eructation, an abdominal distention, a rumble and unpleasant sensations in paraumbilical range) is most often observed.

The bacteriocarrier of Shigellas. Proceeding abjection of Shigellas at the persons who have tolerated an acute dysentery, within 3 months in the absence of clinical symptoms of disease and normal data of a proctosigmoidoscope is the reconvalescent bacteriocarrier.

The transitional bacteriocarrier is a unitary abjection of Shigellas at practically healthy human who was not ill by a dysentery and not having dysfunctions of an intestine throughout last 3 months