Shigellosis: what is it, symptoms, treatment, prognosis, complications

What is shigellosis?

Shigellosis (or bacterial dysentery) Is an infection of the gastrointestinal tract. Everyone is ill, however, the prevalence of this disease is noted among children under 4 years of age (60% of the incidence). This is likely due to the fact that older children and adults are better hygienic.

The predominant spread of infection in the summer-autumn period is recorded, which can be explained by a large number of fruits consumed (not always washed enough), favorable conditions in the warm season for the growth of bacteria in food products.

Causes and risk factors

The causative agent of bacterial dysentery is enterobacteria from the genus Shigella (lat. shigella), hence the name - shigellosis.

Shigellosis is caused by 4 types of shigella:

• s. dysenteriae;
• s. flexneri;
• s. boydii;
• s. sonnei.

They are named so in honor of the scientists who isolated and described these enterobacteria. Varieties of pathogens are characteristic for certain regions. In European countries, dysentery is caused by s. sonnei (shigella Sonne), less often - s. flexneri (Flexner's stick). In Central Asian countries and the Far East, dysentery caused by s. dysenteriae (Grigoriev-Shiga stick) with a more severe course.

Shigella have sufficient stability in the external environment, which allows them to remain in water for more than a week, in soil - up to three months, in food - up to four weeks, tolerate low temperatures and drying. They die under the influence of disinfectants and direct sunlight, when heated to 60 ° C they die in half an hour, and when boiled - instantly.

Source of infection - a sick person and a healthy excretory bacteria of dysentery bacillus. The pathogen is excreted in the feces. The mechanism of infection with dysentery is fecal-oral, that is, the infection penetrates through the digestive tract.

Ways of transmission: bacteria can enter the child's body with food, water or when using household items, as well as if the rules of personal hygiene are not followed (i.e., infection occurs through contact and everyday life). Shigellosis is also sometimes called dirty hands disease. Flies play a role in the transfer of pathogens.

Most often, contamination occurs when drinking raw water, products that are not subjected to heat treatment (e.g. salads, raw milk), expired foods, improperly stored perishable products.

The risk of contracting shigellosis increases with the consumption of unwashed or poorly washed vegetables and fruits. The incidence increases during the ripening period of strawberries, raspberries, grapes. Many parents do not consider it necessary to wash watermelons and melons before giving them to their child.

The disease occurs both in the form of isolated (sporadic) cases, and in the form of outbreaks. A sick person is contagious from the very first day of illness. Dysentery bacillus is excreted in large quantities from the patient's body with feces. In family foci, children become infected in 40% of cases. Babies become infected from their caregivers.

With contact and household infection, the infection is transmitted through dishes, dirty linen, toys, towels and other items. If a patient with dysentery does not wash his hands after visiting the toilet, then on his hands he transfers the pathogen to all objects with which he comes into contact. Then a healthy person uses these objects, and puts the stick into his mouth with his own hands.

Susceptibility to bacterial dysentery is very high in children, especially in the first 3 years of life (60% of patients are only children under 4 years of age). The predisposing factors for the onset of shigellosis are:

• artificial feeding;
• hypotrophy;
• hypovitaminosis;
• chronic diseases of the digestive tract;
• unsanitary conditions in the home.

Immunity after suffering from dysentery is unstable and short-lived, therefore, repeated repeated illness is possible.

Pathogenesis

Shigellosis is a common disease of the whole organism, but the main pathological process predominantly develops in the lower part of the large intestine: the sigmoid colon is affected. Some of the pathogens upon penetration into the body are destroyed in the digestive tract and secrete endotoxin.

The released toxin is absorbed into the bloodstream, affects the vascular wall and increases its permeability, which contributes to the development of pathological changes in the intestine. Shigella multiply in the intestinal mucosa and mesenteric lymph nodes.

The inflammatory process in the mucosa depends on the severity of pathological changes. First, redness and swelling of the mucous membrane with minor hemorrhages develops. Such catarrhal inflammation develops in mild cases of shigellosis. And with a severe course of infection, superficial necrosis of epithelial cells of the mucous membrane develops with the formation of ulcers on the intestinal wall after rejection of necrotic cell layers.

With even deeper necrosis, ulcers appear in the thickness of the intestinal wall, followed by scarring. Other microorganisms (fungi, staphylococci, etc.) can also take part in the formation of such ulcers.

The defeat of the intestinal wall leads to a violation of its function: peristalsis increases, stools become more frequent, mucus appears and blood in stool, there is a spasm of the affected intestine. Shigellosis toxins cause damage to blood vessels and nerve endings not only in the intestine itself, but also in the central nervous system.

This leads to a reflex dysfunction of other organs of the digestive tract (liver, stomach, small intestine, pancreas); as a result, metabolic processes in the body are disrupted. Toxins and under-oxidized metabolic products lead to damage to the cardiovascular system, and to degenerative changes in the internal organs.

Therefore, one should not be frivolous about the disease with shigellosis: the consequences can develop quite serious. Intoxication of the whole body can even lead to death, especially in small and weak children.

The recovery process in the intestine, depending on the degree of damage to the mucous membrane, can last for several weeks. With a sluggish recovery (in a weakened child's body), the disease can take on a chronic course. And the chronic form of the disease leads to hypovitaminosis, malnutrition, the addition of a secondary infection.

Signs and symptoms

The incubation, or latent period with shigellosis is on average 2-3 days; the minimum can be equal to several hours, and the maximum - 7 days. The duration of the incubation period depends on the infectious dose of the pathogen: the more microbes enter the body, the faster the manifestations of the disease appear.

Shigellosis can occur in a typical and atypical (erased) form, have a smooth and uneven (with complications) course. The disease can have different durations: up to two months in the acute form, up to three months in the protracted form, and longer than three months in the chronic one.

The clinical manifestations of dysentery depend on the type of pathogen, the massiveness of the infection, age, severity of the course of the disease, the state of the immune system, and the presence of concomitant diseases. Shigellosis can be mild, moderate, severe and toxic.

Dysentery caused by Sonne's bacillus is more often characterized in children by a light, erased course without necrotic changes in the intestinal mucosa. With Flexner's dysentery, the intestines are more affected, and the disease is more severe.

The onset of shigellosis is acute. The temperature rises to high numbers and lasts for three days. From the first day of illness, signs of intoxication appear: lack of appetite, vomiting (may be repeated), lethargy, headache. Patients complain of cramping pains in the left iliac region, which decrease after the act of defecation.

Stool is frequent, usually more than 5 times (up to 25-30 times in severe cases) per day. At first, the stool is plentiful, then (on the first day or on the second) it becomes scarce, an admixture of mucus and greens appears, and blood streaks may be noted. With moderate and severe infection, the stool in the following days is a scanty spit of green mucus. False painful desires "down" are also characteristic.

Frequent straining in young children leads to a gaping anus, and less often - even to prolapse of the rectal mucosa. The abdomen is painful when palpating along the colon, there is a rumbling in the abdomen.

The severity of the disease depends on the severity of the manifestations of intoxication and the degree of changes in the intestinal mucosa.

At mild form the general condition of the patient practically does not suffer, or is slightly disturbed for a short period of time. Body temperature is usually normal or slightly elevated. The stool is speeded up (up to 8 times a day), has a fecal character with an admixture of a small amount of mucus. There is usually no blood impurity.

At moderate form intoxication is moderately pronounced: the temperature rises to 39 ° C for 2-3 days, the general state of health worsens, vomiting is noted, abdominal pains are cramping. Painful urge to "down" and increased stool (10 or more times per day) are noted for several days, there is mucus streaked with blood in the stool. Stool normalization occurs after 7 (or even 10 days), and an admixture of mucus may be in the decorated stool.

At severe form shigellosis is dominated by intestinal symptoms, although intoxication is also pronounced. Stool with pathological impurities, speeded up (more than 15 times per day). The high temperature during treatment decreases, but it is kept within 37.5 ° C for a long time. Decreased appetite, weakness are also present for a long time.

Recovery and restoration of the intestinal mucosa is slow. With intensive therapy, stool normalization occurs within a week, manifestations of intoxication disappear faster - the disease acquires an abortive course.

At toxic form the main symptom is the manifestation of intoxication in the form of neurotoxicosis. Repeated vomiting, a sharp rise in temperature, a violation of the general condition of the patient in the first hours of the disease are sometimes interpreted as food poisoning, because the change in stool characteristic of dysentery may appear later, after a few hours.

Stool quickly changes from copious to scanty, very frequent, with a lot of mucus and streaked with blood. The abdomen is painful, somewhat sunken, the spasmodic sigmoid colon is palpable.

Severe toxicosis in hypertoxic form can lead to seizures and loss of consciousness. Disturbances from the cardiovascular system are characteristic: the skin is pale, with a bluish tinge, the limbs are cold, blood pressure drops sharply. In some cases, death occurs even before intestinal manifestations.

The duration of the disease and its outcome depend not only on the severity of the process, but also on the patient's age, on the correctness and timeliness of treatment, therefore it is so important to contact a sick child as early as possible for medical help.

- Chronic shigellosis.

Chronic shigellosis develops more frequently in children than in adults. It can occur with any form of the disease. Chronization of the process can be facilitated by rickets, anemia, helminthic invasion, and concomitant diseases. A common cause of the chronic course of shigellosis is re-infection of the child with dysentery bacillus.

The chronic form of bacterial dysentery can occur with mild intoxication. There is lethargy, fatigue, appetite worsens, but the state of health is satisfactory, the temperature is normal. Often worried about pain in the lower abdomen, there is a liquefied stool, sometimes with mucus. Occasionally, streaks of blood may appear in the stool. Loose stools are associated with incomplete restoration of the intestinal mucosa.

In addition to the intestines, other digestive organs are usually involved in the process, and their enzymatic deficiency develops. Long-term indigestion leads to the development of malnutrition, anemia, hypovitaminosis.

The above symptoms can be noted constantly: this is called the continuous course of dysentery. In other cases, chronic dysentery takes on a recurrent course, when exacerbations and periods of well-being alternate.

- Features of the course of the disease at an early age.

In the first year of a child's life, risk factors for the onset of shigellosis are diathesis, artificial feeding, rickets, anemia.

At an early age, the disease has a number of features:

• colitis syndrome develops gradually and can be combined with signs of dyspepsia: the stool remains fecal, fetid, abundant, green, with mucus and undigested lumps; in very rare cases, blood streaks appear;
• the stomach is not drawn in, but swollen;
• restlessness and crying during bowel movements, gaping of the anus;
• toxic forms are rare;
• primary infectious toxicosis is poorly expressed, but secondary toxicosis manifests itself, caused by a violation of metabolic processes; it develops at a later date and is characterized by disorders of water and mineral metabolism and the activity of the cardiovascular system;
• secondary bacterial infection develops more often (pneumonia, otitis);
• there is a tendency to chronicity of the process and the undulating course of the disease.

In infants, secondary toxicosis may be associated with the development of a mixed infection, that is, a combination of dysentery with staphylococcal infection or salmonellosis. In such cases, severe toxicosis develops with a pronounced rise in temperature and a significant decrease in body weight.

Repeated vomiting and watery, profuse enough stools quickly lead the child's body to dehydration. Severe violations of protein metabolism also join water-mineral disorders. Severe bloating develops (flatulence), increased heart rate, there may be a violation of the rhythm of cardiac activity, depression of consciousness and convulsions is possible.

The undulating course of the disease is most often associated with late treatment. In severe cases, cardiac and renal failure.

Diagnostics

The diagnosis takes into account the epidemic situation, clinical manifestations and laboratory examination. The main diagnostic signs of dysentery are the frequency and nature of the stool (scanty, green, mixed with mucus and streaks of blood), the presence of painful false desires "to the bottom", as well as an acute onset of the disease and intoxication syndrome.

From laboratory methods are used:

• Coprogram, or clinical analysis of feces - examination of feces under a microscope; determines the number of leukocytes, red blood cells in feces, neutral fats, muscle fibers, fatty acids and bacteria; the method allows you to indirectly assess the degree of damage to the intestinal mucosa;
• Accurate confirmation of the diagnosis allows obtaining a bacteriological method, sowing feces and vomit: isolation of the causative agent of the disease and determination of its sensitivity to antibiotics;
• Serological reactions of the tested blood (RNGA, ELISA) make it possible to detect in the blood specific antibodies to Shigella and an increase in their titer in the studied paired sera;
• In doubtful cases, it is possible to use the method PCR to identify the causative agent of the disease;
• Sigmoidoscopy: an endoscopic method of examining the rectum and sigmoid colon using a rectoscope inserted through the anus. Allows you to visually identify and assess the condition of the intestinal mucosa. In children with dysentery, it is used extremely rarely.

In the general analysis of blood with a mild form of shigellosis, there are no changes, and in severe forms, there is an increase in the number of leukocytes. ESR may be normal or slightly elevated.

Standard treatments

Treatment includes:

• saline solutions;
• in severe cases, antibiotics.

Water and salt lost due to diarrheaare replenished with fluids taken by mouth or, if the infection is severe, injected into a vein.

Mild forms of infection usually resolved within 4–8 days. Antibiotics are usually not required to treat mild infections in healthy adults.

However, doctors often prescribe antibiotics for some patients, including:

• very young or old patients;
• patients with a weakened immune system;
• patients with moderate or severe infection.

Severe infections may also require hospitalization for intravenous saline infusions, and treatment of complications such as hemolytic uremic syndrome. Antibiotics such as azithromycin, ciprofloxacin (for adults), or ceftriaxone are given.

Drugs to relieve diarrhea (such as diphenoxylate or loperamide) can delay recovery and should not be used.

Forecast

With timely and proper treatment of a sick person, shigellosis is curable. The recovery of children occurs in the absence of complications (usually three or four weeks after the onset of the disease). But the complete recovery of the mucous membrane lasts up to 3 months and longer.

Violation of the diet threatens the occurrence of an exacerbation. The severe course of the disease, the onset of dysentery at an early age of the child and severe toxic syndrome are factors that predispose to a high likelihood of complications.

Complications

Potential complications of shigellosis include:

• intestinal bleeding;
• hemolytic uremic syndrome;
• intestinal perforation with development peritonitis;
• inflammation of the colon peritoneum;
• prolapse of the rectal mucosa;
• cicatricial narrowing of the intestinal lumen;
• development dysbiosis.

Prophylaxis

Prevention is as follows:

• Infected people should not prepare food for other people.
• Infected people should wash their hands after using the toilet. The toilet must be disinfected before using it again.
• Caregivers of people with shigellosis should wash their hands with soap and water, especially before handling other people or eating food.
• Infected children who show symptoms should not come into contact with healthy children.
• Diapers of infected babies should be discarded in a closed trash can. It is also necessary to wipe the baby's swaddling area with disinfectant wipes after each use.
• It is necessary to rinse the stool from the clothes or bedding of infected people with running water. Soiled clothes and bed linen are washed in the washing machine with hot water. Next, wipe the surface of the washbasin, toilet and washing machine with a disinfectant such as diluted bleach containing chlorine.

There are currently no vaccines available yet, but one vaccine is in the research phase.