DEFINITION
A person has diarrhea when they pass thin stool that ranges from very soft to completely watery, several times per day. Diarrhea is a symptom, not a condition by itself, and has several causes, as well as several degrees of severity.

CAUSES AND EPIDEMIOLOGY
Diarrhea can affect anyone. In the industrialized world, episodes of diarrhea are transient and do not constitute an everyday phenomenon; better hygiene and clean drinking water mean that many of the water-borne bacteria that can cause a nasty case of diarrhea are not transmitted to us, at least not often. An average individual will get diarrhea about 4 times a year, for some days, without any complications. However, on a worldwide scale, it has been estimated that about 750.000.000 live in condition with poor or no water sanitation and diarrhea with lots of complications is a more common phenomenon. According to the WHO statistics of 2004, 707.000 people died in Africa from a diarrhea-related disease in that year, as opposed to Europe, where the deaths for 2004 due to diarrheal diseases were 16.000.

In the industrialized world, most cases of diarrhea last for 2-3 days and resolve with no residual damage. Some of the most common causes of diarrhea include: • Bacterial or viral gastroenteritis. Gastroenteritis is an infection, caused by bacteria or viruses, that presents with diarrhea, vomiting, abdominal cramping and nausea. Bacterial gastroenteritis is what we all know as food poisoning, namely consuming food that contains bacteria.
• Parasites. Except for bacterial and viruses, parasites can also cause diarrhea.
• Food intolerance. If you have a certain intolerance to an ingredient, consuming it will lead to diarrhea.
• Food allergy.
• Hyperthyroidism. An over-working thyroid is likely to lead to diarrhea amongst other symptoms.
• Diseases of the gastrointestinal tract, such as Crohn’s disease or ulcerative colitis.

PRESENTATION
It is considered that a person is affected by diarrhea when they pass more than 3 stools per day (or more than whichever number of stools is normal for each person and the texture of the stool ranges from very soft to liquidy. Diarrhea begins suddenly and abdominal cramps are usually present as well. It lasts for less than a week, there is no blood in the stool, and typically, a person feels the need to empty their bowels suddenly and intensely each time. Restraining the wish to “go” does not work most of the times, and the individual needs to run to the bathroom. You may also feel bloated, and fever can co-exist too. Most of the times, this type of diarrhea is not dangerous and will resolve or get a lot better after 2 or 3 days; there are some cases, however, in which a more dangerous bacterium or parasite is involved and medical care is required. People who risk serious complications from this type of diarrhea are the elderly and the very young; many episodes of watery diarrhea each day can lead to dehydration and, in extreme cases, death. Signs of dehydration include dry lips and mouth, paper-like, dry skin, disorientation and fainting.

There are two other types of diarrhea, linked to more dangerous germs: dysentery and persistent diarrhea. Dysentery is diarrhea with blood in the stool, anorexia, and rapid weight loss, severe pain in the abdomen, nausea, fever and, in extreme cases a delirium. Dysentery will cause complications if left untreated and medical help is needed. Persistent diarrhea is a state that begins with watery or dysenteric diarrhea but lasts for more than 2 weeks and is an infectious cause. It can also lead to dehydration because of the prolonged time that a person loses fluid and salt through diarrhea.

WHEN TO SEEK TREATMENT
Most of the time that a person has diarrhea, it is not necessary to visit the doctor. Contact you, doctor, immediately, if:
• You notice blood in your stools.
• You have a very high fever, over 100.4 degrees Fahrenheit.
• The episodes of diarrhea are too many and make you feel exhausted and unable to perform simple tasks
• You suffer from nausea and vomiting and cannot drink water to replenish the lost fluid
• You begin having fits of diarrhea after returning from a foreign country, especially from Africa or Asia.
• Diarrhea persists for more than 3 days without getting better.
• You are a senior citizen, with other co-existing conditions or if your child has diarrhea that does not resolve after a couple of days.

WORKUP
The examinations and procedures you need to undergo to determine the cause of diarrhea vary, depending on the symptoms. In most cases, no laboratory tests are carried out; the doctor will take a detailed history, carry out a physical examination of the abdomen and, if no other alarming symptoms, signs of dehydration or significant risk exist, the diagnosis is simple. In other cases, you may need to give some blood so that a complete blood count can be carried out, in order to see if white blood cells exist and what type and what is your general status. Electrolytes may be measured too because they are lost with diarrhea when it is severe. An abdominal ultrasound and an x-ray may also be required. Colonoscopy is used to evaluate the colon sometimes as well. A stool culture can show which type of bacteria or parasites have caused the episodes of diarrhea.

TREATMENT
If you have a mild episode of diarrhea, with no other alarming symptoms you can do the following at home to provide relief:
• Drink plenty of fluids, so that you can stay hydrated.
• If you vomit as well, wait for a minimum of 2 hours before you begin to drink water. Start by drinking very small amounts and, if you can tolerate it, continue to drink throughout the day.
• Adapt your diet. Eat small amounts of simple foods, mainly carbs, such as potatoes, plain pasta, and bread. You can also eat hard-boiled eggs. Avoid dairy products, fried food, vegetables, and fruit.
• Rest.
If anything concerns you, call your doctor. If you experience dehydration signs, see blood in your stool or have persistent diarrhea and fever, contact your doctor. They may prescribe pills to relieve nausea and in some cases antibiotics to fight the microorganisms that have invaded the gastrointestinal tract.

POPULAR MISCONCEPTIONS
• I avoid people who have had diarrhea in the past few days because I will get it too.
Diarrhea can be caused by many things. Most of the causes aren’t transmitted when you casually find yourself in the company of someone who has them, such as food poisoning, bowel diseases, and others. Make sure you wash your hands after visiting the bathroom if someone who has used it has diarrhea; touching surfaces with germs (because the microorganisms exist in the stool) and then touching your food will likely cause you to have the symptom yourself.

• When I get diarrhea, I wait for it to resolve in a couple of days. Last week I was in Asia and when I returned I started experiencing diarrhea again. I’ll wait.
Having diarrheal symptoms under the same circumstances, e.g without changing something in your daily routine is not something to worry about, if it happens once in a while. Visiting a foreign country, however, and especially Africa, Asia or any tropical region, means that your diarrhea may be caused by a more serious microorganism. Contact your doctor.

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