What is Diarrhea?
Diarrhea is an increase in the frequency of bowel movements or a decrease in the form of stool (greater looseness of stool). Although changes in frequency of bowel movements and looseness of stools can vary independently of each other, changes often occur in both.
Diarrhea needs to be distinguished from four other conditions. Although these conditions may accompany diarrhea, they often have different causes and different treatments than diarrhea. These other conditions are:
- Incontinence of stool, which is the inability to control (delay) bowel movements until an appropriate time, for example, until one can get to the toilet
- Rectal urgency, which is a sudden urge to have a bowel movement that is so strong that if a toilet is not immediately available there will be incontinence
- Incomplete evacuation, which is a sensation that another bowel movement is necessary soon after a bowel movement, yet there is difficulty passing further stool the second time
- Bowel movements immediately after eating a meal
What causes Diarrhea?
Acute diarrhea is usually caused by a bacterial, viral, or parasitic infection. Chronic diarrhea is usually related to a functional disorder such as irritable bowel syndrome or an intestinal disease such as Crohn’s disease.
The most common causes of diarrhea include the following:
- Bacterial infections. Several types of bacteria consumed through contaminated food or water can cause diarrhea. Common culprits include Campylobacter, Salmonella, Shigella, and Escherichia coli (E. coli).
- Viral infections. Many viruses cause diarrhea, including rotavirus, norovirus, cytomegalovirus, herpes simplex virus, and viral hepatitis. Infection with the rotavirus is the most common cause of acute diarrhea in children. Rotavirus diarrhea usually resolves in 3 to 7 days but can cause problems digesting lactose for up to a month or longer.
- Parasites. Parasites can enter the body through food or water and settle in the digestive system. Parasites that cause diarrhea include Giardia lamblia, Entamoeba histolytica, and Cryptosporidium.
- Functional bowel disorders. Diarrhea can be a symptom of irritable bowel syndrome.
- Intestinal diseases. Inflammatory bowel disease, ulcerative colitis, Crohn’s disease, and celiac disease often lead to diarrhea.
- Food intolerances and sensitivities. Some people have difficulty digesting certain ingredients, such as lactose, the sugar found in milk and milk products. Some people may have diarrhea if they eat certain types of sugar substitutes in excessive quantities.
- Reaction to medicines. Antibiotics, cancer drugs, and antacids containing magnesium can all cause diarrhea.
Some people develop diarrhea after stomach surgery, which may cause food to move through the digestive system more quickly.
People who visit certain foreign countries are at risk for traveler’s diarrhea, which is caused by eating food or drinking water contaminated with bacteria, viruses, or parasites. Traveler’s diarrhea can be a problem for people traveling to developing countries in Africa, Asia, Latin America, and the Caribbean. Visitors to Canada, most European countries, Japan, Australia, and New Zealand do not face much risk for traveler’s diarrhea.
In many cases, the cause of diarrhea cannot be found. As long as diarrhea goes away on its own within 1 to 2 days, finding the cause is not usually necessary.
- Watery, liquid stools: The stools may be any color. The passage of red stools suggests intestinal bleeding and could be a sign of a more severe infection. The passage of thick, tarry black stools suggests significant bleeding in the stomach or upper portions of the intestine and is not usually caused by acute infections. The diarrhea may appear green in color, because stool passes through the intestines faster than usual.
- Abdominal cramps: Occasionally diarrhea is accompanied with mild-to-moderate abdominal pain. Severe abdominal or stomach pain is not common and, if present, may suggest more severe disease.
- Fever: A high fever is not common. If present, the affected person may have a more severe illness than acute diarrhea.
- Bloating and gas
- The urgent feeling or need to have a bowel movement
- Dehydration: If diarrhea leads to dehydration, it is a sign of potentially serious disease.
Signs and symptoms of dehydration include:
- Adults may be very thirsty and have a dry mouth.
- The skin of older people may appear to be loose. The elderly may also become very sleepy or have behavioral changes and confusion when dehydrated.
- Dehydrated infants and children may have sunken eyes, dry mouths, and urinate less frequently than usual. They may appear very sleepy or may refuse to eat or drink.
There are many strains of E. coli bacteria. Most of the E. coli bacteria are normal inhabitants of the small intestine and colon and are non-pathogenic, meaning they do not cause disease in the intestines. Nevertheless, these non-pathogenic E. coli can cause diseases if they spread outside of the intestines, for example, into the urinary tract (where they cause bladder or kidney infections) or into the blood stream (sepsis).
Certain strains of E. coli, however, are pathogenic (meaning they can cause disease in the small intestine and colon). These pathogenic strains of E. colicause diarrhea either by producing toxins (called enterotoxigenic E. coli or ETEC) or by invading and inflaming the lining of the small intestine and the colon and causing enterocolitis (called enteropathogenic E. coli or EPEC). Traveler’s diarrhea usually is caused by an ETEC strain of E. coli that produces a diarrhea-inducing toxin.
Tourists visiting foreign countries with warm climates and poor sanitation (Mexico, parts of Africa, etc.) can acquire ETEC by eating contaminated foods such as fruits, vegetables, seafood, raw meat, water, and ice cubes. Toxins produced by ETEC cause the sudden onset of diarrhea, abdominal cramps, nausea, and sometimes vomiting. These symptoms usually occur 3-7 days after arrival in the foreign country and generally subside within 3 days. Occasionally, other bacteria or parasites can cause diarrhea in travelers (for example, Shigella, Giardia, and Campylobacter). Diarrhea caused by these other organisms usually lasts longer than 3 days.
What’s the Treatment for Diarrhea on Traveler
If your case is mild, you may not need to take anything. Or you can take an over-the-counter medicine such as bismuth subsalicylate (Pepto-Bismol, Kaopectate) or loperamide (Imodium) which are available as liquids or tablets. Follow the instructions on the package.
If you have itching, burning, soreness, or pain in your rectal area because you have a lot of bowel movements, try these tips to feel better:
- Take a warm bath. Afterwards, pat the area dry (do not rub) with a clean, soft towel.
- Use a hemorrhoid cream or try white petroleum jelly.
Do your best to stay hydrated. You should drink at least six 8-ounce glasses of fluid each day. Choose fruit juice without pulp, broth, or soda (without caffeine). Chicken broth (without the fat), tea with honey, and sports drinks are also good choices.