Lecture of bacillary dysentery (shigellosis)

2021-04-15 04:08 PM

The shigellas are both enterotoxins (ShET-1) and ShET-2, they alter electrolyte transport in the cells of the colon mucosa, causing increased secretion.


Bacillary dysentery is an inflammatory colorectal disease caused by the Shigella bacillus. The typical acute form with clinical manifestations is fever, frequent bowel movements, bloody and mucous stools, abdominal cramping and painful defecation. The disease spreads through the gastrointestinal tract and easily develops into an epidemic.

Research history

Bacillary dysentery has been around for a long time. But it was not until 1896 during an outbreak of bacillary dysentery in Japan that the author Shiga discovered the pathogen as Shigella shiga. In 1900 Flexneri and Strong discovered Shigella flexneri. Later Boyd, Lentz and many other authors discovered other strains of dysentery that cause disease in humans.



Shigella bacillus, catch gram (-) color, no shell, no hair, no spores. Shigella has O-body antigens, H-antigens free. Based on O antigens and biochemical properties, Shigella is divided into 4 groups with many serotypes:

Group A: Sh. dysenteriae: there are 15 serotypes, notably Sh.dysenteriae type 1 (Sh. shiga).

Group B: Sh. flexneri (there are 8 serotypes).

Group C: Sh. boydii (19 serotypes).

Group D: Sh. sonnei (has 1 serotype).

In Shigella strains, attention should be paid to Sh. dysenteries type 1 (Sh. shiga) because it has a very toxic Shiga (shiga-toxin) toxin. This toxin is similar to that of Enterohemorrhagic Escherichia coli or causes microvascular complications, hemolytic urea syndrome (H .U .S) and thrombocytopenic haemorrhage. Shigella shiga differs from other Shigella in three important points:

Often causing large and prolonged outbreaks.

Antibiotic resistance was more common than other strains.

It often causes dysentery more severe, lasts longer and causes more death than other strains.

The shigellas are both enterotoxins (ShET-1) and ShET-2, they alter electrolyte transport in the cells of the colon mucosa, causing increased secretion.

Shigella bacillus exists in freshwater, raw vegetables, food for 7-10 days at room temperature. in contaminated fabrics, in soil: 6-7 weeks. However, quickly destroyed in boiling water, under sunlight and conventional disinfectants.


Are people suffering from bacillary dysentery (these types: acute, subacute, chronic) or asymptomatic carriers ..


Spread the digestive tract through drinking water, food, contaminated hands and flies.

Depression and immunity

Translation properties.

Everyone can get it, especially children under 3 years old. Immunity after the illness is weak, unstable, lasts 1 to 2 years, only specific to one strain. There is no cross-immunity.

The disease is found all over the world but mainly in hot and underdeveloped countries.

The disease occurs spread all year round, often becoming epidemic in the summer. The epidemic can range from a few dozen to hundreds with.

In Vietnam: Bacillus dysentery is one of the two infectious diseases with the largest number of people infected (viral hepatitis and bacillary dysentery). There are all 4 Shigella groups present, the most prominent are two Sh groups. dysenteriae and Sh. flexneri. Recent years is Sh. Flexneri and Sh.sonney.

Mechanism of pathogenesis and pathology

Mechanism of pathogenesis

Bacillus from mouth to the stomach, due to its high resistance to acids, it overcomes the acid barrier in the stomach to the small intestine and then down to the colon to break into the colon mucosa and cause disease. The dysentery bacillus can penetrate the mesenteric lymph node but usually does not spill into the blood (Only in severely immunocompromised sites such as HIV infected patients with AIDS can the Shigella bacillus break into the blood).

In the colon mucosa, bacillus dysentery causes inflammation, secretion, bleeding, destruction of the mucosal epithelial cell layer; at the same time releasing toxins. Toxins work on the system causing infection - intoxication syndrome, cardiovascular symptoms, urinary etc. In place, the toxin affects the motor nerves, the sensory system and the flora causing symptoms of pain, burning, diarrhoea many times, bloody stools, pus, sometimes only diarrhoea. Simple. Disorders the functions of the intestine, imbalance of water, electrolytes and acidosis.

Facing the impact of bacteria and dysentery, the body will mobilize all defence mechanisms to eliminate bacteria from the body.

Pathological anatomy

Pathological lesions in bacillary dysentery are mainly in the colon, especially the descending colon, the sausage colon and the rectum. There can also be damage to the small intestine and stomach.

Lesions of the colon mucosa are usually broad, with a pattern of exudative inflammation, bleeding, and shallow and broad ulcers. Severe forms may have necrotic clusters, bruised, gray, pseudo-membrane, deep ulcers from the epithelium to the muscle layer. Or leave sequelae atrophy, intestinal narrowing, chronic colitis. Particularly, causing perforation of the colon causes peritonitis.


Classification of bacillary dysentery according to the clinical form

Acute bacillary dysentery

Typical body type: Light, moderate, and severe.

Atypical form: The gastrointestinal tract; Dark form.


Chronic bacillary dysentery

Asymptomatic carriers

Clinical practice of some diseases

Clinical examination of acute, typical, moderate bacillary dysentery

Incubation period From 1-3 days.

Onset: The disease usually has a sudden and rapid onset of episode.

Full play:

Toxic infection syndrome:

Usually fever 38-39 ° C, with cold spines, accompanied by headache, fatigue, insomnia, loss of appetite. The number of leukocytes and neutrophils in peripheral blood is usually increased (sometimes normal or decreased).

Dysentery syndrome:

 Dull abdominal pain along the colon frame especially the colon down, left pelvic fossa and hypotension. Alternately, there is sharp pain that makes the patient burn away. When going out, she has to push a lot (but there is no sign of "going out fake"). At first the stools are still liquid, then there is no stool, only mucus and blood. The mucus is often thinly cloudy, like pus mixed with blood, with no clear boundaries. Sometimes the stools have a lot of water color thanks to the fish blood or meat wash mixed with the mucus.

Dehydration syndrome, electrolytes:

Thirst, dry lips, little urination, but pulse and blood pressure are normal. When going out a lot, there is a decrease in Na +, Cl-, K + and HCO3-etc ...


With good treatment, patients can recover after 7-14 days. If treatment is not good, the disease can turn into serious form.

Clinical diagnosis of severe acute bacillary dysentery

Usually caused by Sh. shiga triggers.

Dark form: Usually occurs in healthy children.

The disease comes on quickly from the start with moderate dysentery syndrome but very severe neurotoxicity with a fever of 40-41 ° C or more. Patient is lethargic, delirious, convulsive and quickly lethargic. Accompanied by heart failure and respiratory failure, causing rapid death after 24 to 48 hours.

Acute bacillary dysentery with severe toxicity: It often occurs in malnourished children, the elderly.

Usually, onset as moderate and worsens with:

Severe dysentery syndrome: Frequent abdominal pain, uncountable defecation, even the stool that flows spontaneously through the anus dilates due to paralysis of the anus the stool contains only pus and blood or necrotic mucosal plaque.

The syndrome of toxic infections is also very severe: Usually the fever is above 40 ° C (although in the elderly, the exhausted person may have a slight or no fever) the expression is pale, pale, pale, drowsy, leading to a coma ...

The overall condition is thin, possible vomiting, hiccups, thirst, dry lips, sunken eyes, very little urination, cold limbs, sweaty stains, small tachycardia, low blood pressure. Laboratory tests: often reduce red blood cells, increase neutrophils.

These can be treated well, but usually last long, recover slowly and often leave many complications and sequelae.

Acute gastroenteritis form

Patients often have fever, abdominal pain in the epigastric region and around the navel, nausea and vomiting, and frequent diarrhea.

This form is common in young children and is often caused by Sh. sonnei.

This can easily lead to dehydration, electrolyte disturbances and severe alkaline acidosis if not treated promptly.

Complications and sequelae


Complications in the intestine:

Bowel bleeding, bowel necrosis, intestinal perforation, peritonitis, intussusception, rectal prolapse. Toxic megacolon aneurysm with or without perforation.


Cholecystitis, urinary tract infections, pneumonia, intestinal candidiasis, septicemia caused by intestinal bacilli. AIDS patients may develop sepsis caused by Shigella.

Systemic complications:

Seizures, neurotoxicity, cardiovascular collapse, thrombophlebitis.

Hemolytic-uremic syndrome (Haemolytic Uraemic Syndrom = HUS): Usually caused by Sh. dysenteriae type I (Sh. shiga). This is a rare but serious complication of dysentery, affecting the blood clotting system and kidneys. There are usually 3 symptoms: hemolytic anemia, thrombocytopenia and kidney failure. If severe, it can cause severe anemia, blood clotting disorders, bleeding under the skin, mucous membranes and kidney failure, often requiring hemodialysis. Test: Low Hematocrit, red blood cells, decreased platelet count, blood specimen has more broken red blood cells, high blood urea and creatinine, high blood potassium.

Reiter's syndrome: With trisomy (arthritis, urethritis, eye conjunctivitis) does not because pus caused by Chlamydia. Usually appears 2-3 weeks after the bacillary dysentery (can also appear immediately in the full-blown stage). This trisomy can appear simultaneously or individually. Previously considered this syndrome as a complication, now considered it a companion with dysentery.


Post-dysentery chronic colitis.


Bacillary dysentery can cause death in severe, long-term intoxication, and death from complications. The mortality rate (in the absence of effective early treatment) is 1% to 10% depending on the country (World Health Organization 1995).

Implementing the quadrants


There are 2 symptoms of infectious infection and dysentery manifest clearly as described above. Colonoscopy shows the entire rectal mucosa - colon congestion, edema, with many shallow and widespread ulcers.


Fecal examination: Seeing many red blood cells and neutrophils, no erythrocytic amoeba can be found.

Stool culture: Seeing that Shigella bacillus has decisive diagnostic value. In the absence of inoculation, the character of the stool is important for diagnosis.


 In the same family, group and at the same time there are many people with the same.

Differential diagnosis

With amoebic dysentery

There are several other characteristics of bacillary dysentery:

Usually not obvious toxic infection syndrome: No fever or mild fever, less systemic affected.

The dysentery syndrome has features: Often abdominal pain in the right pelvic fossa, with signs of "going fake". The number of going out is small (from 5-15 times / day). The mucus and blood are usually separate, the mucus is clear like banana resin, and are small in quantity and sticky.

Microscopy: There are many monocytes; have large erythrocytic amoeba (with decisive diagnostic value).

Colonoscopy: Seeing small, deep ulcers, with frayed margins, on the almost normal mucosal floor, sparse, scattered lesions.

With Salmonella food poisoning infection

 Different bacillary dysentery in some points:

Incubation time is usually shorter than bacillary dysentery.

Usually the fever is 39-40 ° C high and has chills.

Gastroenteritis syndrome is prominent from the outset with severe vomiting, epigastric pain and peri-navel pain, easy bowel movements, and rarely any pressure. Watery feces, many times the volume of undigested food.


Often faster than bacillary dysentery.

However, there are cases where it is difficult to distinguish clinically, only fecal culture can distinguish it.

Irritable bowel syndrome

Usually there is no fever, little changes in the body.

Dysentery syndrome: Usually occurs in relation to after eating certain foods such as: Fat, tanh, etc. Expression of dysentery is usually mild.

History: Has suffered the same many times.

Test: Many times no amoeba was detected.

Fecal culture: Many times, stool cultures did not show bacillus dysentery.

With haemorrhagic diarrhoea caused by "invasive" E. coli type

It is strain E. coli 0157. Has caused major outbreaks in Europe, North America, South Africa and recently in Japan. Due to eating undercooked beef and drinking fresh cow's milk contaminated with E. coli 0157.

Clinical manifestations: Also fever, bloody diarrhea due to intestinal haemorrhage. 5% - 10% of patients have hemolytic-uremic syndrome (HUS).

The differential diagnosis is mainly based on bacterial cultures.

With intestinal dysbiosis

Usually occurs after long-term, broad-spectrum, high-dose oral antibiotics. The patient often had diarrhea several times; loose stools or defecate fat. Due to poor absorption and poor appetite, the body is exhausted, anemia, edema, low fever. Blood tests: Leukocytes increased, neutrophils increased, blood sedimentation increased.

The intestinal lice test showed that E. coli normally decreased to less than 70% of the aerobic bacteria in the intestine.

Also need to differentiate from dysentery syndrome caused

High blood urea.

Contamination of mercury, lead, zinc, etc.

Colon cancer, colon polyps.

Fibroids, cancer, uterine abscesses, ovarian cysts. Fibroids, prostate cancer or abscesses, purulent inflammation, abscesses, bladder cancer.

Acute appendicitis.


Treatment of bacillary dysentery must be comprehensive combining antibacterial treatment with symptomatic treatment, complication treatment, nutrition, care and disinfection.


Principles of using antibiotics

Bacillus dysentery, especially Sh strain. Shiga has been highly resistant to drugs previously used to treat such as sulfamic, tetracycline, chloramphenicol and recently found resistance to ampicillin and Bactrim. Therefore, the selection of the appropriate antibiotic must be based on the results of antibiotic mapping with dysentery isolated at the place where the epidemic occurs. If not based on the latest susceptibility test results of dysentery (especially Sh. Shiga) circulating locally. The principle of using antibiotics in treatment is: Do not use high doses, do not use a combination of broad-spectrum antibiotics, do not use for a long time.

The current recommended medications for the treatment of bacillary dysentery by the World Health Organization-1995 are:

For mild and moderate forms, use

Ampicillin:      Adults 1g / time ' 4 times / day ' 5 days.
Children 25mg / time ' 4 times / day ' 5 days.

TMP + SMX (Trimethoprim + Sulfamethoxazol):

Adults: 160 mg TMP / time ' 2 times / days ' of 5 days.
SMX 800 mg / time ' 2 times / days ' 5 days

Children: TMP 5mg / kg heavy / time ´ 2 times / day ´ 5 days SMX 25mg / kg heavy / time ´ 2 times / day ´ 5 days

A.Nalidixic: From 15 to 20 mg / kg / time x 4 times / day for 5 days

For heavy use

Generation 2 quinolones such as:

Ciprofloxacin: Adults 500mg / times ' 2 times / days ' of 5 days.

                                   Children 15 mg / kg / time ' 4 times / day ' 5 days

Enoxacin: Adults 200mg / time ´ 2 times / day ´ 5 days.

                                   Children 5 mg / kg / time ' 4 times / day ' 5 days

Pefloxacin: Adults 400mg / times ' 2 times / days ' 5 days

Ofloxacin: Adults 200mg / times ' 2 times / days ' 5 days

Currently ampicillin and TMP + SMX have suffered from Sh. Shiga resistance was widespread, but other Shigella were still active. New quinolones such as Ciprofloxacin, Enoxacin etc. resistance is very rare, should be used to treat severe dysentery caused by Sh. shiga. However, with children under 12 years old should be cautious because Quinolone affects the development of joint cartilage. The choice of the above antibiotic for treatment depends on the circumstances and the specific clinical situation.

The oriental medicine can be used to treat mild and moderate bacillary dysentery such as: Becberin, papyrus, mitochondrial apricot leaf + egg, etc.

Symptomatic treatment


Dehydration - electrolytes will worsen dysentery and cause many complications. Therefore, it is necessary to accurately assess the situation of electrolyte dehydration.

Mild dehydration

Oral rehydration solution (ORESOL). If not, use the soup, yogurt, and water often mixed with a little salt just enough to use.

Moderate and severe dehydration

Combined oral ORESOL (if not vomiting) and intravenous infusion of Ringer lactate solutions, 0.9% Natricloride combined with 5% Glucose ...

If there is a lack of K +

K + supplementation orally (Kaleorid: 2g-4g / day) or intravenously (Kalicloride) depending on the degree of potassium loss. When acidosis, add sodium bicarbonate.

Cardiovascular support

Use Spartein 0.05 ´ 1-2 ampoules / day (intramuscularly) for tachycardia using Uabain 1/4 mg ´ 250ml 5% Glucose solution by slow intravenous infusion.


Vitamin B1 is used 30mg - 50 mg/day by injection or by mouth.

Vitamin C 500 mg/day intravenously or orally.


Apply warm compresses to the painful area.

Drink belladon solution 10-15 drops / time ´ 2-3 times / day if you need to administer atropine 1 / 4mg ´ 1-2 doses / day (under the skin).

Note: Do not use drugs with opium preparations such as: Paregoric alcohol, washing tablets, opizoic, etc. to handle diarrhoea and pain relief.

Anti-high fever

When fever is> 39 ° C in children prone to seizures, use gardenal sedatives 2-4 mg/kg/day and reduce the fever with cold compress, rubbing alcohol, fan, taking paracetamol 20mg-30 mg/kg / 24 hours.

Treat other symptoms

When the stools are slowly forming a mold: Enema keep with a solution of 0.02% ´ 100-150ml of purple medicine / day.

When prolonged dysentery, anorexia use hydrochloric acid solution + pepsin 1 tablespoon / time. Take before meals 15 minutes or neopeptine (capsule) 1 capsule / time x 2 times / day.


Along with antibiotics, nourishment plays a very important role in the treatment of dysentery. The general rule is:

During the first few days in the acute phase, the digestive system can work lightly, then quickly recover from a near normal diet.

Do not let starve for more than 24 hours. Do not limit food for more than 3-4 days.

The first week, eat foods that are easy to digest, and nutritious. Avoid foods high in fiber, solid, fatty, and spicy foods.

Eat many meals, each meal a little (avoid eating more in 1 meal). Breastfed babies: still breastfeed when sick.

Aide - Disinfection disinfection - Standard discharge

Nurse. Follow

Feces: Number of times, weight, properties, fecal culture before and after treatment.

Pulse, temperature, blood pressure, urine.

Dehydration, mental disorder.

Disinfection disinfection

Fertilizer: 1 part of fertilizer + 1/2 part of lime chloride for 2 hours or 1 part of fertilizer + 2 parts of 3% chloride solution for 30 minutes.

Duck meat: Soak in chloramine 3% solution for 1 hour.

Chamber: Disinfection with Cresyl 5%, Cloramin 3%.

Ca, cups, dishes: boiled.

Criteria for discharge

Clinical recovery + no bacteria excretion (Fecal culture 2 times, no bacteria found or after 10-20 days of treatment if the stool cannot be cultured).


Patients with dysentery, after being discharged from the hospital, should not be arranged as alimony or supplies. While still having to do these tasks, they should be closely and regularly monitored.


Personal hygiene

Sanitize hands before eating, eating, and drinking.


Hygiene in circumstances: feces, water, garbage.

Food Hygiene.

Kill the flies.

Propaganda and education to improve the hygiene level for everyone. Combine reminder to check the cleaning modes for good.