Dysentery: Definition, Types, Causes, Symptoms, Diagnosis, Treatment and Advice


Dysentery is an intestinal inflammation, especially in the colon, leading to severe diarrhea with mucus or blood in the stool.

Patients usually experience mild to severe stomach aches or abdominal cramps. In some cases, dysentery that is not treated can be fatal, especially if the infected person can not replace the lost fluids quickly enough.

When people in industrialized countries have dysentery, the signs and symptoms tend to be mild. Many do not even go to their doctor, and the problem is solved in a few days.

There are two main types of dysentery:

  • Bacillary dysentery, caused by Shigella, a bacterium, is the most common type among people who have not been recently in the tropics.
  • Amoebic dysentery (amebiasis) is caused by Entamoeba histolytica, a type of amoeba, and is more common in the tropics.

An amoeba is a protozoan organism (unicellular) that changes shape constantly. Approximately 1.1 million people die from Shigella infection worldwide each year. Sixty percent of these deaths occur in very young children.

Causes of dysentery

Dysentery is caused mainly by a protozoon or bacteria (a cellular organism, such as an amoeba). A parasitic worm infestation can also cause it. Rarely, a viral infection or chemical irritant can also be a cause.


A symptom is something that the patient feels, whereas a sign is something other people see, such as the doctor. For example, pain can be a symptom, while a rash can signify.


Some symptoms of dysentery are:

  • Abdominal pain, diarrhea, and fatigue.
  • Patients with mild symptoms will have mild stomach pain (cramps) and often go to the bathroom because of diarrhea.
  • Symptoms usually appear between one and three days after the person has been infected – this is called the incubation period. In most cases, the patient recovers completely within a week.
  • In some cases, people with dysentery may also develop lactose intolerance.


A stool sample will usually be required for analysis if a physician suspects dysentery. For bacterial infections such as Shigella, the diagnosis is made by stool culture.

Unfortunately, such cultures are not available in most developing countries, and diagnosis is made clinically based on the symptoms.

Amoebiasis is often diagnosed by finding parasites under a microscope. A blood test of antibodies helps confirm the diagnosis of amoebic dysentery or liver abscess.

The  E. histolytica has a “twin” identical,  Entamoeba dispar; under the microscope, a harmless amoeba is similar to  E. histolytica. It never produces symptoms and does not require treatment.

In developing countries, the distinction is usually not made: individuals who have amoeba in their bowel movements are treated regardless of whether the infection is causing the symptoms. Of those diagnosed with amoebae in their feces, 90% have harmless  E. dispar.


Rehydration therapy: initially, this is done by oral rehydration; The patient is recommended to drink plenty of fluids.

Diarrhea and vomiting result in the loss of fluids that have to be replaced to avoid dehydration. If diarrhea and vomiting are profuse, the medical team may recommend intravenous fluid replacement.

Antibiotics and drug amoebicide: experts say that, if possible, the administration of drugs to kill the cause of dysentery should be withheld until laboratory tests determine whether the disease is caused by bacteria or amoeba.

If this is not possible, depending on the severity of the symptoms, the patient can receive combinations of antibiotics, medication, and amebicide.

If the symptoms are not severe and the doctor determines that it is bacillary dysentery (Shigella), it is more likely that he will not receive the medication (in the vast majority of cases, the illness will resolve within a week). Oral rehydration is essential.

Antiparasitic medications such as metronidazole and iodoquinol are commonly used to treat dysentery caused by amebiasis. 

Antibiotics such as ciprofloxacin, ofloxacin, levofloxacin, or azithromycin are used to treat organisms that cause bacillary dysentery.

People with prolonged diarrhea should consult their doctor. If you are traveling, you should take a regimen of self-treatment antibiotics for one to three days, such as ciprofloxacin, and use it in the case of a sudden moderate to severe diarrheal disease.

The bismuth subsalicylate (Pepto-Bismol ®) may also be helpful for some travelers. Also, use antidiarrheal loperamide to reduce bowel speed and prevent dehydration. Consult your doctor for children under two years of age.

It is essential to replace fluids lost with diarrhea. Soft drinks, juices, and bottled water will suffice in mild cases. The most severe diarrhea should be treated with solutions that contain electrolytes such as potassium, salt, and sucrose.

For severe diarrhea, commercial oral rehydration solutions are usually needed. These solutions are available in packages to facilitate the trip. People should try to consume enough fluids, so that clear to light yellow urine is produced every 3 to 4 hours.

Although dysentery affects it, it is better to follow a soft diet (bananas, rice, crackers) and avoid dairy products.

Dysentery can be prevented to some extent by practicing careful personal hygiene.

People who travel or live in areas with high rates of dysentery should follow the following tips:

  • Do not eat food cooked in unhygienic circumstances, such as street vendors.
  • Only eat cooked foods that have been heated to a high temperature. Do not eat cooked foods that have cooled.
  • Do not eat raw vegetables. Avoid fruit species without shells. Open fruits with shells yourself.
  • Drink only bottled or boiled water commercially. Do not use ice unless it has been made with purified water.
  • Use only bottled or boiled water to wash and cook food, wash your hands and brush your teeth.
  • Consider traveling with an alcohol-based hand sanitizer.