|Written by:||Betty W.|
Dysentery, infectious disease characterized by inflammation of the intestine, abdominal pain, and diarrhea with stools that often contain blood and mucus. Dysentery is a significant cause of illness and death in young children, particularly those who live in less-developed countries. There are two major types: bacillary dysentery and amebic dysentery, caused respectively by bacteria and by amoebas.
Bacillary dysentery, or shigellosis, is caused by bacilli of the genus Shigella. Symptomatically, the disease ranges from a mild attack to a severe course that commences suddenly and ends in death caused by dehydration and poisoning by bacterial toxins. After an incubation period of one to six days, the disease has an abrupt onset with fever and the frequent production of watery stools that may contain blood. Vomiting may also occur, and dehydration soon becomes obvious owing to the copious loss of bodily fluids. In advanced stages of the disease, chronic ulceration of the large intestine causes the production of bloody stools.
The most severe bacillary infections are caused by Shigella dysenteriae type 1 (formerly Shigella shigae), which is found chiefly in tropical and subtropical regions. S. flexneri, S. sonnei, and S. boydii are other Shigella bacilli that cause dysentery. Other types of bacterial infections, including salmonellosis (caused by Salmonella) and campylobacteriosis (caused by Campylobacter), can produce bloody stools and are sometimes also described as forms of bacillary dysentery. The treatment of bacillary dysentery is based on the use of antibiotics. The administration of fluids and, in some cases, blood transfusions may be necessary.
Amebic dysentery, or intestinal amebiasis, is caused by the protozoan Entamoeba histolytica. This form of dysentery, which traditionally occurs in the tropics, is usually much more chronic and insidious than the bacillary disease and is more difficult to treat because the causative organism occurs in two forms, a motile one and a cyst, each of which produces a different disease course. The motile form causes an acute dysentery, the symptoms of which resemble those of bacillary dysentery. The cyst form produces a chronic illness marked by intermittent episodes of diarrhea and abdominal pain. Bloody stools occur in some patients. The chronic type is the more common of the two and is marked by frequent remissions and exacerbations of symptoms. The chronic form may also produce ulcerations of the large intestine and pockets of infection in the liver. Both forms of amebic dysentery are treated with drugs that specifically kill the amebic parasites that thrive in the intestines.
Dysentery is transmitted through the ingestion of food or water that has been contaminated by the feces of a human carrier of the infective organism. The transmission is often by infected individuals who handle food with unwashed hands. The spread of amebic dysentery is often accomplished by people who are carriers of the disease but who at the time show no symptoms. Dysentery is commonly found when people are crowded together and have access only to primitive sanitary facilities. Spread of the disease can be controlled by boiling drinking water and by adequately disposing of human waste to avoid the contamination of food.
Other symptoms may include:
- abdominal cramps or pain
- fever of 100.4°F (38°C) or higher
- dehydration, which can become life-threatening if left untreated
Dysentery is usually spread as a result of poor hygiene. For example, if someone who has dysentery doesn’t wash their hands after using the toilet, anything they touch is at risk.
The infection is also spread through contact with food or water that has been contaminated with fecal matter. Careful hand washing and proper sanitation can help prevent dysentery and keep it from spreading.
Types of dysentery
Most people who experience dysentery develop either bacterial dysentery or amebic dysentery.
Bacterial dysentery is caused by infection with bacteria from Shigella, Campylobacter, Salmonella, or enterohemorrhagic E. coli. Diarrhea from Shigella is also known as shigellosis. Shigellosis is the most common type of dysentery, with about 500,000 cases diagnosed in the United States each year.
Amebic dysentery is caused by a single-celled parasite that infects the intestines. It’s also known as amebiasis.
Amebic dysentery is less common in the developed world. It’s usually found in tropical locales that have poor sanitary conditions. In the United States, most cases of amebic dysentery occur in people who have traveled to an area where it’s common.
What causes dysentery and who is at risk?
Shigellosis and amebic dysentery typically result from poor sanitation. This refers to environments where people who don’t have dysentery come into contact with fecal matter from people who do have dysentery.
This contact may be through:
- contaminated food
- contaminated water and other drinks
- poor hand washing by infected people
- swimming in contaminated water, such as lakes or pools
- physical contact
Children are most at risk of shigellosis, but anyone can get it at any age. It’s easily spread through person-to-person contact and by contaminated food and drink.
Shigellosis mostly spreads among people who are in close contact with an infected person, such as people:
- at home
- in day care centers
- in schools
- in nursing homes
Amebic dysentery is primarily spread by eating contaminated food or drinking contaminated water in tropical areas that have poor sanitation.
How is dysentery diagnosed?
If you or your child has symptoms of dysentery, see your doctor. If left untreated, dysentery can lead to severe dehydration and become life-threatening.
At your appointment, your doctor will review your symptoms and any recent travels. You should note any travels outside of the country. This information can help your doctor narrow down the possible cause of your symptoms.
Many conditions can cause diarrhea. If you don’t have other symptoms of dysentery, your doctor will order diagnostic testing to determine which bacteria are present. This includes a blood test and a lab test of a stool sample.
Your doctor may also perform addition testing to decide whether an antibiotic will help.
Mild shigellosis is usually treated just with rest and plenty of fluids. Over-the-counter medication, such as bismuth subsalicylate (Pepto-Bismol), can help relieve cramps and diarrhea. You should avoid drugs that slow down the intestines, such as loperamide (Imodium) or atropine-diphenoxylate (Lomotil), which can make the condition worse.
Severe shigellosis can be treated with antibiotics, but the bacteria that causes it are often resistant. If your doctor prescribes an antibiotic and you don’t see improvement after a couple of days, let the doctor know. Your strain of Shigella bacteria may be resistant, and your doctor may need to adjust your treatment plan.
Amebic dysentery is treated with metronidazole (Flagyl) or tinidazole (Tindamax). These drugs kill the parasites. In some cases, a follow-up drug is given to make sure all the parasites are gone.
In severe cases, your doctor may recommend an intravenous (IV) drip to replace fluids and prevent dehydration.
In some cases, dysentery can lead to complications. These include:
Postinfectious arthritis: This affects about 2 percent of people who get a particular strain of the Shigella bacteria called S. flexneri. These people can develop joint pain, eye irritation, and painful urination. Postinfectious arthritis can last for months or years.
Blood stream infections: These are rare and most likely to affect people with weak immune systems, such as people with HIV or cancer.
Seizures: Sometimes young children can have generalized seizures. It isn’t clear why this happens. This complication generally resolves without treatment.
Hemolytic uremic syndrome (HUS): One type of Shigella bacteria, S. dysenteriae, can sometimes cause HUS by making a toxin that destroys red blood cells.
In rare cases, amebic dysentery can result in liver abscess or parasites spreading to the lungs or brain.