Shigellosis (bacterial dysentery)

Shigellosis (bacterial dysentery, Shigellosis, dysenterya) is an acute infectious disease caused by bacteria of the genus Shigella with a fecal-oral mechanism of transmission of the pathogen and characterized by a picture of distal colitis and intoxication. Symptoms of dysentery include fever, nausea, vomiting and diarrhea, which is usually bloody in nature. Diagnosis of dysentery is based on the clinic and is confirmed by culture research. Treatment of dysentery is supportive and is mainly aimed at rehydration and administration of antibiotics (eg, ampicillin or trimethoprim-sulfamethoxazole). These drugs are the drugs of choice.

ICC codes 10

• A03.0. Dysentery caused by Shigella dysenteriae.
• A03.1. Dysentery caused by Shigellaflexneri.
• A03.2. Dysentery caused by Shigella boydii.
• A0Z.Z. Dysentery caused by Shigella sonnei.
• A03.8. Another dysentery.
• A03.9. Dysentery, unspecified.

What causes dysentery?

The species of Shigella is ubiquitous and is a typical cause of inflammatory dysentery. It is the shigella that causes 5-10% of diarrheal diseases in many regions. Shigella are divided into 4 main subgroups: A, B, C and D, which in turn are divided into specific serological types. Shigella flexneri and Shigella sonnei are found more frequently than Shigella boydii, and especially the virulent Shigella dysenteriae. Shigella Sonnei is the most common isolate in the United States.

The source of infection are the feces of sick people and convalescents. Direct spread is carried out by the fecal-oral route. Mediated spread is through contaminated food and objects. Fleas can serve as carriers of shigella. The most common epidemics occur in densely populated populations with inadequate sanitation. Dysentery especially occurs in young children living in endemic regions. In adults, the resulting dysentery usually does not go so badly.

Recovering and subclinical carriers can be a serious source of infection, but long-term carrier of this microorganism is rare. Dysentery almost does not leave behind itself immunity.

The causative agent penetrates the mucosa of the lower intestine, which causes mucus secretion, hyperemia, leukocyte infiltration, edema and often superficial ulceration of the mucosa. Shigella dysenteriae type 1 (not found in the US) produces Shiga toxin, which causes severe watery diarrhea and sometimes hemolytic-uremic syndrome.

What are the symptoms of dysentery?

Dysentery has an incubation period of 1-4 days, after which typical symptoms of dysentery appear . The most frequent manifestation is watery diarrhea, which is indistinguishable from diarrhea that occurs with other bacterial, viral and protozoal infections, in which there is increased secretory activity of the intestinal epithelial cells.

In adults, dysentery can begin with episodes of cramping abdominal pain, urging for defecation and defecation with decorated feces, after which temporary relief of pain occurs. These episodes are repeated with increasing severity and frequency. Diarrhea acquires a pronounced character, while the stool can be soft, liquid, contain an admixture of mucus, pus and often blood. Rectal prolapse and consequent incontinence of the stool can be the cause of acute tenesmus. In adults, the manifestation of infection can occur without fever, with diarrhea, in which there is no mucus or blood in the stool, and with little or no tenes. Dysentery usually ends in recovery. In the case of a moderate infection, this occurs after 4-8 days, in the case of an acute infection, after 3-6 weeks. Severe dehydration with loss of electrolytes and circulatory collapse and death usually occurs in weakened adults and children younger than 2 years.

Rarely dysentery begins suddenly with diarrhea rice decoction and a serous (in some cases bloody) stool. The patient may develop vomiting, and he can quickly get dehydrated. Dysentery can manifest by the appearance of delirium, convulsions and coma. At the same time, diarrhea is weak or nonexistent. Death can occur within 12-24 hours.

In young children dysentery begins sudden. This causes fever, irritability or tearfulness, loss of appetite, nausea or vomiting, diarrhea, abdominal pain and bloating, as well as tenesmus. Within 3 days in the stool there are blood, pus and mucus. The number of defecations can reach more than 20 per day, with the loss of body weight and dehydration becoming acute. In the absence of treatment, a child may die within the first 12 days of the disease. In those cases when the child survives, the symptoms of dysentery gradually decrease by the end of the second week.

Secondary bacterial infections may occur, especially in weakened patients and in patients with dehydration. Acute ulceration of the mucous membrane can lead to acute blood loss.

Other complications are rare. These may include toxic neuritis, arthritis, myocarditis, and rarely intestinal perforation. Hemolytic-uremic syndrome can complicate shigellosis in children. This infection can not take a chronic course. Also, it is not an etiological factor of ulcerative colitis. In patients with the HLA-B27 genotype, after shigellosis and other enteritis, reactive arthritis more often develops.

How is dysentery diagnosed?

Diagnosis is made by a simpler high index of suspicion of shigellosis during outbreaks, the presence of disease in endemic regions and the detection of leukocytes in the stool in the study of smears stained with methylene blue or Wright's dye. The culture of the stool can be diagnosed, and therefore it should be carried out. In patients with symptoms of dysentery (presence of mucus or blood in the stool) differential diagnosis of dysentery with invasive E. Coli, salmonella, iersiniosis, campylobacteriosis, as well as amoebiasis and viral diarrhea is necessary.

The surface of the mucous membrane when viewed by the rectoscope diffusively erythematous with a large number of small ulcers. Despite the fact that the number of leukocytes is reduced at the beginning of the disease, on average, it is 13x109. Haemoconcentration is often found, as well as metabolic acidosis caused by diarrhea.

How is dysentery treated?

Dysentery is treated symptomatically by administration of oral or intravenous fluids. Antibiotics can neutralize the symptoms of dysentery due to dysentery and mucosal damage, but their appointment is not mandatory in generally healthy adults with mild infection. Children, elderly people, weakened and patients with acute infection should receive dysentery treatment with antibiotics. In adults, fluoroquinolone, such as ciprofloxacin, 500 mg orally for 3-5 days or trimethoprim-sulfamethoxazole, two tablets in a single dose every 12 hours is the drug of choice for this infection. In children, treatment is done with trimethoprim-sulfamethoxazole at a dose of 4 mg / kg orally every 12 hours. Calculation of the dosage is carried out using a trimethoprim component. Many Shigella isolates are more likely to be resistant to ampicillin and tetracycline.

How is dysentery prevented?

Dysentery is prevented if you wash your hands thoroughly before preparing food, and dirty clothes and bed linens are placed in closed containers with soap and water until they are able to boil them. Patients and carriers should use the correct insulation techniques (especially for stools). A living vaccine is being developed from Sonne's dysentery, and studies conducted in endemic regions give hope for success. Immunity is usually type-specific.