Dysentery is an acute intestinal infection caused by bacteria of the genus Shigella, characterized by the predominant localization of the pathological process in the mucous membrane of the large intestine. Dysentery is transmitted by fecal-oral route (food or water). Clinically, a dysentery patient has diarrhea, abdominal pain, tenesmus, intoxication syndrome (weakness, weakness, nausea). The diagnosis of dysentery is established when the pathogen is isolated from the patient’s bowel movements, with Grigoriev-Shiga dysentery – from the blood. Treatment is carried out mainly on an outpatient basis and consists of rehydration, antibacterial and detoxification therapy.
General information
The causative agents of dysentery are shigella, currently represented by four species (S. dysenteriae, S.flexneri, S. boydii, S. Sonnei), each of which (with the exception of shigella Sonnei) is in turn divided into serovars, of which there are currently more than fifty. The population of S. Sonnei is homogeneous in antigenic composition, but differs in its ability to produce various enzymes. Shigella are immobile gram–negative rods, do not form spores, reproduce well on nutrient media, are usually poorly resistant in the external environment.
The optimal temperature environment for shigella is 37 ° C, Sonne sticks are capable of reproduction at a temperature of 10-15 ° C, can form colonies in milk and dairy products, can remain viable in water for a long time (like Flexner shigella), are resistant to antibacterial agents. Shigella quickly die when heated: instantly – when boiling, after 10 minutes – at a temperature of more than 60 degrees.
The reservoir and source of dysentery is a person – a sick or asymptomatic carrier. Patients with mild or erased dysentery are of the greatest epidemiological importance, especially those related to the food industry and catering establishments. Shigella are isolated from the body of an infected person, starting from the first days of clinical symptoms, the contagion persists for 7-10 days, followed by a period of convalescence, during which, however, the release of bacteria is also possible (sometimes it can last several weeks and months).
Flexner’s dysentery is most prone to transition to a chronic form, the least tendency to chronization is noted in infection caused by Sonne bacteria. Dysentery is transmitted by the fecal-oral mechanism mainly by food (Sonne dysentery) or by water (Flexner dysentery). During the transmission of Grigoriev-Shiga dysentery, a contact-household transmission path is mainly implemented.
People have a high natural susceptibility to infection, after suffering from dysentery, unstable type-specific immunity is formed. Those who have had Flexner’s dysentery can maintain postinfectious immunity, which protects against repeated disease for several years.
Pathogenesis
Shigella enter the digestive system with food or water (partially dying under the influence of acidic stomach contents and normal intestinal biocenosis) and reach the colon, partially penetrating into its mucous membrane and causing an inflammatory reaction. The mucosa affected by shigella is prone to the formation of areas of erosion, ulcers, hemorrhages. Toxins secreted by bacteria disrupt digestion, and the presence of shigella destroys the natural biobalance of the intestinal flora.
Classification
Currently, the clinical classification of dysentery is used. Its acute form is distinguished (it differs in predominant symptoms into typical colitic and atypical gatroenteritic), chronic dysentery (recurrent and continuous) and bacterial excretion (convalescent or subclinical).
Dysentery symptoms
The incubation period of acute dysentery can last from one day to a week, most often it is 2-3 days. The colitic variant of dysentery usually begins acutely, the body temperature rises to febrile values, symptoms of intoxication manifest themselves. Appetite is noticeably reduced, may be completely absent. Sometimes nausea and vomiting are noted. Patients complain of intense cutting pain in the abdomen, initially diffused, later concentrating in the right iliac region and lower abdomen. The pain is accompanied by frequent (up to 10 times a day) diarrhea, bowel movements quickly lose their fecal consistency, become scarce, pathological impurities are noted in them – blood, mucus, sometimes pus (“rectal spit”). The urge to defecate is excruciatingly painful (tenesmus), sometimes false. The total number of daily bowel movements, as a rule, is not large.
On examination, the tongue is dry, overlaid with plaque, tachycardia, sometimes arterial hypotension. Acute clinical symptoms usually begin to subside and finally fade away by the end of the first week, the beginning of the second, but ulcerative mucosal defects usually heal completely within a month. The severity of the course of the colitic variant is determined by the intensity of intoxication and pain syndrome and the duration of the acute period. In severe cases, disorders of consciousness caused by severe intoxication are noted, the frequency of stool (according to the type of “rectal spit” or “meat slops”) reaches dozens of times a day, abdominal pain is excruciating, significant hemodynamic disorders are noted.
Acute dysentery in the gastroenteric variant is characterized by a short incubation period (6-8 hours) and mainly enteral signs against the background of a general intoxication syndrome: nausea, repeated vomiting. The course resembles that of salmonellosis or toxicoinfection. The pain in this form of dysentery is localized in the epigastric region and around the navel, has a cramping character, the stool is liquid and abundant, there are no pathological impurities, dehydration syndrome may occur with intense fluid loss. The symptoms of gastroenteritis are violent, but short-term.
Initially, gastroenterocolitic dysentery also resembles food toxicoinfection in its course, later colitic symptoms begin to join: mucus and bloody streaks in the feces. The severity of the gastroenterocolitic form is determined by the severity of dehydration.
Dysentery of the erased course occurs quite often today. There is discomfort, moderate abdominal pain, mushy stools 1-2 times a day, mostly without impurities, hyperthermia and intoxication are absent (or extremely insignificant). Dysentery lasting more than three months is recognized as chronic. Currently, cases of chronic dysentery in developed countries are extremely rare. The recurrent variant is periodic episodes of the clinical picture of acute dysentery, interspersed with periods of remission, when patients feel relatively well.
Continuous chronic dysentery leads to the development of severe digestive disorders, organic changes in the mucous membrane of the intestinal wall. Intoxication symptoms with continuous chronic dysentery are usually absent, there is constant daily diarrhea, bowel movements are mushy, may have a greenish tinge. Chronic malabsorption disorders lead to weight loss, hypovitaminosis, and the development of malabsorption syndrome. Convalescent bacterial excretion is usually observed after acute infection, subclinical – it happens when dysentery is transferred in an erased form.
Complications
Complications at the current level of medical care are extremely rare, mainly in the case of severe Grigoriev-Shiga dysentery. This form of infection can be complicated by infectious-toxic shock, intestinal perforation, peritonitis. In addition, the development of intestinal paresis is likely.
Dysentery with intense prolonged diarrhea can be complicated by hemorrhoids, anal fissure, rectal prolapse. In many cases, dysentery contributes to the development of dysbiosis.
Diagnostics
Bacteriological diagnostics is as specific as possible. The pathogen is usually isolated from feces, and in the case of Grigoriev-Shiga dysentery – from blood. Since the increase in the titer of specific antibodies occurs rather slowly, the methods of serological diagnostics (IHT) have retrospective significance. Increasingly, the laboratory practice of diagnosing dysentery includes the detection of shigella antigens in feces (usually produced with the help of CR, LAT, ELISA and IHT with antibody diagnostics), the compliment binding reaction and the aggregation of hemaglutination.
As general diagnostic measures, various laboratory techniques are used to determine the severity and prevalence of the process, to identify metabolic disorders. The analysis of feces for dysbiosis and coprogram is carried out. Endoscopic examination (rectoromanoscopy) can often provide the necessary information for a differential diagnosis in doubtful cases. For the same purpose, patients with dysentery, depending on its clinical form, may need to consult a gastroenterologist or proctologist.
Dysentery treatment
Mild forms of dysentery are treated on an outpatient basis, inpatient treatment is indicated for people with severe infection, complicated forms. Also, patients are hospitalized for epidemiological indications, in old age, with concomitant chronic diseases, and children of the first year of life. Patients are prescribed bed rest for fever and intoxication, dietary nutrition (in the acute period – diet No. 4, when diarrhea subsides – table No. 13).
Etiotropic therapy of acute dysentery consists in prescribing a 5-7-day course of antibacterial agents (antibiotics of the fluoroquinolone, tetracycline series, ampicillin, cotrimoxazole, cephalosporins). Antibiotics are prescribed for severe and moderate forms. Taking into account the ability of antibacterial drugs to aggravate dysbiosis, eubiotics are used in a complex course for 3-4 weeks.
If necessary, detoxification therapy is performed (depending on the severity of detoxification, drugs are prescribed orally or parenterally). Correction of absorption disorders is performed with the help of enzyme preparations (pancreatin, lipase, amylase, protease). According to the indications, immunomodulators, antispasmodics, astringents, enterosorbents are prescribed.
Microclysms with infusion of eucalyptus and chamomile, rosehip and sea buckthorn oil, vinylin are recommended to accelerate regenerative processes and improve the condition of the mucosa during convalescence. The chronic form of dysentery is treated in the same way as acute, but antibiotic therapy is usually less effective. It is recommended to prescribe therapeutic enemas, physiotherapeutic treatment, bacterial agents to restore normal intestinal microflora.
Prognosis and prevention
The prognosis is mostly favorable, with timely complex treatment of acute forms of dysentery, chronization of the process is extremely rare. In some cases, after infection, residual functional disorders of the large intestine (postdysentery colitis) may persist.
General measures for the prevention of dysentery imply compliance with sanitary and hygienic standards in everyday life, in food production and at catering establishments, monitoring the condition of water sources, sewage waste treatment (especially disinfection of wastewater from medical institutions).
Patients with dysentery are discharged from the hospital no earlier than three days after clinical recovery with a negative single bacteriological test (sampling of material for bacteriological examination is carried out no earlier than 2 days after the end of treatment). Food industry workers and other persons equated to them are subject to discharge after a double negative result of bacteriological analysis.
