Dr. Ertan Beyatlı

What are the causes of diarrhea?

(Update: ) - Digestive System Diseases

Diarrhea or diarrhea (Latin: Diarrhea or diarrhoea "running away") is a condition in which stools are often watery or soft. Diarrhea is definitely not a disease, but a symptom of polfactory origin.

Diarrhea is the second largest cause of death (after pneumonia) in the world under the age of five, 1,5 million babies die annually in this way. The biggest cause of these deaths in underdeveloped countries is the lack of adequate clean water and inadequate waste water treatment capacity; Contamination of sewage water to drinking water is also an important reason.

What Causes Diarrhea?

Diarrhea has many causes (polyfactory). It can also be caused by taking too much vitamin C or magnesium. The most important causes in terms of human and animal health are infectious diseases. Diarrhea together stomach pain, nausea and vomiting may also occur. The medical definition of diarrhea includes the production of more than 200 grams of stool per day, as some features of diarrhea can be seen in other conditions.

Diarrhea occurs when the large intestine does not absorb enough fluid. Normally, the meal is mixed with large amounts of water, both as part of the digestive process and due to drinking liquids. Therefore, digested food is essentially liquid before it reaches the large intestine. The large intestine absorbs the water and makes the remaining material semi-solid. If the large intestine is damaged or inflamed, water absorption is blocked and watery stool occurs.

The most common cause of diarrhea is viral infection or bacterial toxins. Except for diarrhea, in healthy living conditions and when there is plenty of food and water, a healthy person gets rid of a viral infection in a few days, at most in a week. On the other hand, diarrhea in sick or malnourished people can cause serious dehydration and can be life-threatening if not treated.

Diarrhea can also be a symptom of more serious illness; for example dysentery, cholera, botulism or Crohn's disease It may indicate a chronic condition such as. Appendicitis Although diarrhea is not common in patients, it is a common symptom of appendiceal rupture. It is also a consequence of radiation sickness. Lactose intolerant Nutrition can cause diarrhea in those with.

The treatment of diarrhea is for the patient to take enough water to replace the lost water, preferably the water should have electrolytes in the water to provide the necessary salt and some nutrients. For most people, no other treatment is required. However, the following types of diarrhea are generally medical supervision is recommended.

  • Diarrhea in infants;
  • Moderate or severe diarrhea in young children;
  • Diarrhea mixed with blood;
  • Diarrhea for more than two weeks;
  • Diarrhea associated with general illness such as non-cramping abdominal pain, weight loss;
  • Diarrhea in those who travel in underdeveloped countries because they are more likely to have unfamiliar infections such as parasites.
  • Food preparers because they are more likely to infect others.
  • Diarrhea in hospitals, pediatric care, geriatric (elderly) or rehabilitation centers.

Causes Diarrhea? (Mechanism of Diarrhea)

Diarrhea can occur by four different mechanisms:
Osmotic diarrhea: The presence of non-absorbable or poorly absorbed substances creates an osmotic pressure between feces and intestinal cells. Because of this pressure difference, water comes out of the cells. Conditions that cause osmotic pressure are malabsorption, some constipation medications, and antacids containing magnesium. The most important reason is the consumption of excessive liquid food.

Secretory diarrhea: In this type of diarrhea, there is a defect in the ion transport mechanisms of the intestinal epithelial cells, resulting in excessive water secretion, insufficient water absorption, or both. This is the case with cholera and enterotoxigenic E. coli infections. Hyperthyroidism, celiac diseaseThis mechanism is also dominant in diseases such as collagenous colitis. Some constipation medications also work this way.

Changes in mobility. This can work in two different ways:

Excessive mobility: The water it carries cannot be absorbed by the body, as the stool passes through the intestine before it comes into contact with the cells long enough. Reasons for this include hyperthyroidism, spastic colon syndrome (IBS)carcinoid syndrome, after gastrectomy and after vagotomy.

Little mobility: There is excessive bacterial growth, so bile salts are broken down, leading to oily stools and diarrhea.
Since it is often difficult to diagnose movement disorders, it is judged to be the only remaining option after other mechanisms are excluded.

These above mentioned mechanisms do not always work alone. For example, absorption disorders in infectious and inflammatory diarrhea can lead to both osmotic diarrhea and active water secretion.

Digestion and Absorption SiteWater (ml)Sodium-Potassium (mMol / lt)Anions (mMol / lt)Osmolarity (mosm / lt)
The first part of the small intestine7504545290
Middle section of the small intestine10007070290
Small-large intestine transition zone7504545290

What is acute diarrhea?

This is defined as diarrhea that lasts less than two weeks and is also called enteritis. It is almost always caused by an infection.

In acute diarrhea, it is sufficient to reassure the patient, to ensure that they take enough fluid and wait. In severe cases or when understanding the cause of the disease is important, stool cultures are taken.
The most common organisms are Campylobacter (animal origin), Salmonella (also of animal origin), Cryptosporidium (animal origin), Giardia lamblia (living in drinking water). Shigella (dysentery), which is less common, is generally of human origin. Cholera is rare in developed countries, usually associated with contamination of sewage water with utility water. Escherichia coli is also probably a very common cause of diarrhea, but difficult to recognize with routine technology. The types of E. coli differ from region to region and from country to country.

Viruses, especially rotavirus, are common in children. Norwalk virus is rare.
Toxins and food poisoning are among the causes of diarrhea. These include staphylococci (usually due to an infected wound in someone who prepares dairy products) and Bacillus cereus toxins. Often "food poisoning" is actually Salmonella infection. Another cause of diarrhea is foodstuffs containing indigestible material, such as olestra.

Parasites and intestinal worms can also cause diarrhea, but there is also weight loss, irritability, redness and itching in the anus. Most commonly, pinworm (a nuisance rather than a serious medical problem). Other worms, hookworm, ascaris and tapeworm are medically more important, they can cause weight loss, anemia, weakness and allergy problems. Amoeba dysentery caused by Entamoeba histolytica can cause bloody diarrhea. Requires proper medical care.

What is chronic diarrhea?

Prolonged diarrhea is rare. Although diarrhea caused by some organisms lasts for years, it does not cause a long-term illness. In such cases, the patient usually improves over time, but becomes a carrier, that is, the infection continues without the patient. This situation requires treatment, especially for food service providers and corporate workers.

Parasites (amoebae and worms) must be treated. Salmonella is the most common stubborn bacteria seen in humans.


These are usually serious medical problems. Absorption disorder (malabsorption) is the problem of the small intestine not absorbing food, sometimes the problem can also be caused by the pancreas.

Causes include: celiac disease lactose intolerance, fructose malabsorption, pernicious anemia pancreatic secretory disorders (short bowel syndrome, radiation fibrosis (usually following cancer treatment) and certain medications)

Inflammatory bowel disease

There are two types, similar characteristics, the reasons are unknown:
Ulcerative colitis is chronic bloody diarrhea and inflammation of the portion of the large intestine close to the rectum.

Crohn's disease affects certain parts of the large intestine and often the ends of the small intestine.

Spastic colon syndrome

Spastic bowel syndrome (Restless bowel syndrome). Defining symptoms: abdominal discomfort or pain with defecation, abnormal stools (diarrhea, constipation, or both), or frequency of bowel movements for at least 3 days a week for the past 3 months. Symptoms of this syndrome can be seen in various conditions such as food allergy, infective diarrhea, celiac disease, and inflammatory bowel disease.

Treating the condition that causes the symptoms usually resolves the diarrhea problem. Spastic colon syndrome may cause excessive intestinal sensitivity (visceral hypersensitivity). Although there is no direct cure for undiagnosed spastic colon syndrome, its symptoms can be controlled with dietary changes, soluble fiber, and medication, including diarrhea.

Other important reasons

Ischemia-induced bowel disease. It usually occurs in older people and is caused by clogged arteries.
Colon cancer. Diarrhea can be seen in some bowel cancers. It is common in colon cancer.

Hormone secreting tumors. Some hormones (eg serotonin) can cause diarrhea if they are secreted in excess (usually by a tumor).
The passage of bile salts into the large intestine instead of being absorbed in the small intestine can cause diarrhea. Bile salt diarrhea is a possible side effect of gallbladder surgery. It is usually treated with cholestyramine, a bile salt release agent.


Chronic diarrhea can also be caused by alcohol consumption [5]. Alcohol consumption reduces the body's ability to absorb water. It is a symptom of a hangover after drinking a lot of alcohol. When alcohol is absorbed from the intestinal cells, it causes them to lose their ability to absorb water and, conversely, to release water. Diarrhea can last several hours until the alcohol is detoxified and flushed from the digestive system. The severity and duration of this type of diarrhea depend on the amount of alcohol consumed and physiological differences.

Improving diarrhea

The body's water ratio should be maintained with properly balanced electrolytes. This is the most appropriate treatment for all types of diarrhea, even dysentery. Drinking large quantities of water without balancing with electrolyte can lead to electrolyte imbalance, which in rare cases is fatal (water poisoning). It should be eaten regularly, as frequent and small meals. It should not be eaten or drunk too quickly. Sometimes, especially in children, dehydration can be life-threatening and intravenous fluids may be required.

Oral rehydration therapy.

It is in the form of taking a salt or sugar solution orally.

Opioids. Opioids and their derivatives should not be taken for infectious diarrhea, because they increase the duration of the disease and increase the risk of conversion to carrier. Opioids are the most effective diarrhea medications. Their main mechanism of action is to inhibit peristalsis.

Loperamide (also known as Imodium) is the most common forehead diarrhea medication.

Others (in order of increasing potency):

Lomotil (diphenoxylate veatropin); Motofen (atropine with difenoxin); codeine; paregoric (camphorated tincture of opium); opium water (laudanum); and morphine. The strongest opioids are reserved for chronic diarrhea (eg from AIDS complications).

Antibiotics. If a bacterium is suspected to be the cause of diarrhea and the person is medically ill, antibiotics may be required. Parasite-induced diarrhea (eg giardiasis) also requires appropriate antibiotics. Antibiotics are not used routinely because diarrhea is rarely caused by bacterial and their use can disrupt the intestinal flora and worsen diarrhea.

Diarrhea and pseudomembranous colitis caused by Clostridium difficile are frequently caused by antibiotic use.
Nutrition regulation. Celiac patients should avoid wheat products. Patients with spastic colon syndrome may change their diet to reduce the overreaction to the gastrocolic reflex that causes diarrhea. Taking soluble fiber foods, using soy and rice products instead of dairy products, being careful while eating fruits and vegetables with high fiber content (insoluble), eating regular and small meals can help reduce the symptoms of spastic colon syndrome.

Foods that should be avoided or minimized, red meat, fatty or fried meals, dairy products (although not lactose intolerant), chocolate, coffee (regular or caffeine-free), alcohol, sodas (especially sorbitol-containing) and artificial sweeteners. Studies have shown that spastic colon syndrome patients are hypersensitive to fats, insoluble fibers and fructose. Hygiene and isolation prevent the spread of the disease.

Some Practical points about diarrhea:

- Patients with diarrhea should be advised to drink plenty of clean fluids (such as water or diluted orange juice). There may be temporary intolerance to lactose, a sugar found in milk, and milk is not recommended as this may aggravate diarrhea.

- It is not recommended for a person with diarrhea to starve, but heavy, fatty and spicy foods should be avoided. Breastfeeding should continue with a bottle, but it may be beneficial to dilute the milk in half with boiled and chilled water. Breastfeeding should be continued normally.

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