Diarrhea is a very common problem in children (see also Diarrhea in adults). Diarrhea is frequent, loose, or watery bowel movements (BMs) that differ from a child’s normal pattern. Sometimes diarrhea contains blood or mucus. Identifying mild diarrhea may be difficult because in healthy children, the number and consistency of BMs vary with age and diet. For example, breastfed infants who are not yet receiving solid food often have frequent, loose stools that are considered normal. A sudden increase in number and looseness may indicate diarrhea in these infants. However, having watery stools for more than 24 hours is never normal.
Children with diarrhea may lose their appetite, vomit, lose weight, or have a fever. If diarrhea is severe or lasts a long time, children are likely to lose a significant amount of body fluid (dehydration). Infants and young children can become dehydrated more quickly, sometimes in less than 1 day. Severe dehydration can cause seizures, brain damage, and death.
Worldwide, diarrhea causes 1.5 to 2.5 million deaths a year. In the United States, diarrhea accounts for about 9% of hospitalizations for children under 5 years old.
Causes of Diarrhea in Children
Likely causes of diarrhea depend on whether it lasts less than 2 weeks (acute) or more than 2 weeks (chronic). Most cases of diarrhea are acute.
Common causes
Acute diarrhea is usually caused by
Infectious gastroenteritis
Use of antibiotics
Gastroenteritis is usually caused by a virus, but it can be caused by bacteria or a parasite.
Food poisoning usually refers to diarrhea, vomiting, or both caused by eating food contaminated by toxins produced by certain bacteria, such as staphylococci or clostridia.
Certain antibiotics can alter the types and number of bacteria in the intestine. As a result, diarrhea can occur. Sometimes using antibiotics enables a particularly dangerous bacteria, Clostridioides difficile (formerly Clostridium difficile), to multiply. Clostridioides difficile releases toxins that can cause inflammation of the lining of the large intestine (colitis— see Clostridioides (formerly Clostridium) difficile–Induced Colitis).
Chronic diarrhea is usually caused by
Dietary factors, such as lactose intolerance or overconsumption of certain foods
Infections (particularly those caused by parasites)
Less common causes
Acute diarrhea can also result from more serious disorders such as appendicitis, intussusception, and hemolytic-uremic syndrome (a complication of certain types of bacterial infection). These serious disorders are usually associated with other worrisome symptoms besides diarrhea, such as severe abdominal pain or swelling, bloody stools, fever, and ill appearance.
Chronic diarrhea can also result from disorders that interfere with the absorption of food (malabsorption disorders), such as cystic fibrosis, and a weakened immune system (due to a disorder such as AIDS or use of certain drugs).
Diarrhea sometimes results from constipation. When hardened stool accumulates in the rectum, soft stool may leak around it and into the child's underwear.
Evaluation of Diarrhea in Children
Warning signs
Certain symptoms are cause for concern. They include
Signs of dehydration, such as decreased urination, lethargy or listlessness, crying without tears, extreme thirst, and a dry mouth
Ill appearance
High fever
Blood in stool
Pain in the abdomen and, when touched, extreme tenderness
Bleeding in the skin (seen as tiny reddish purple dots [petechiae] or splotches [purpura])
When to see a doctor
Children with any warning signs should be evaluated by a doctor right away, as should those who have had more than 3 or 4 episodes of diarrhea and are not drinking or are drinking very little.
If children have no warning signs and are drinking and urinating normally, the doctor should be called if diarrhea lasts 2 days or more or if there are more than 6 to 8 episodes of diarrhea a day. If diarrhea is mild, a doctor’s visit is unnecessary. Children with diarrhea for 14 days or more should be seen by a doctor.
What the doctor does
Doctors first ask questions about symptoms and medical history. Doctors then do a physical examination. What they find during the history and physical examination often suggests a cause and the tests that may need to be done ( see Table: Some Causes and Features of Diarrhea).
Doctors ask what the BMs look like, how frequent they are, how long they last, and whether the child has other symptoms, such as fever, vomiting, or abdominal pain.
Doctors also ask about potential causes, such as diet, use of antibiotics, consumption of possibly contaminated food, recent contact with animals, and recent travel.
A physical examination is done, looking for symptoms of dehydration and disorders that can cause diarrhea. The abdomen is checked for swelling and tenderness. Doctors also evaluate the child's growth.
Testing
If diarrhea lasts less than 2 weeks and warning signs are not present, the cause is probably gastroenteritis due to a virus, and testing is usually unnecessary. However, if doctors suspect another cause, tests are done to check for it.
Tests are typically done when children have warning signs. If they have signs of dehydration, blood tests are done to measure levels of electrolytes (sodium, potassium, calcium, and other minerals necessary to maintain the fluid balance in the body). If other warning signs are present, tests may include a complete blood cell count, urine tests, examination and analysis of stool, abdominal x-rays, or a combination.
Treatment of Diarrhea in Children
Specific causes of diarrhea are treated. For example, if children have celiac disease, gluten is removed from their diet. Antibiotics that cause diarrhea are stopped if a doctor recommends it. Gastroenteritis due to a virus usually disappears without treatment.
Dehydration
Because the main concern in children is dehydration, treatment is focused on rehydrating by giving fluids and electrolytes ( see also Dehydration in Children). Most children with diarrhea are successfully treated with fluids given by mouth (orally). Fluids are given by vein (intravenously) only if children are not drinking, are vomiting a lot, or are severely dehydrated. Oral rehydration solutions that contain the right balance of carbohydrates and sodium are used. In the United States, these solutions are widely available without a prescription from pharmacies and most supermarkets. Sports drinks, sodas, juices, and similar drinks have too little sodium and too much carbohydrate and should not be used.
If children are also vomiting, small, frequent amounts of fluid are given at first. Typically, 1 teaspoon (5 milliliters) is given every 5 minutes. If children keep this amount down, the amount is gradually increased. If the child is not vomiting, the initial amount of fluid does not need to be limited. With patience and encouragement, most children can take enough fluid by mouth to avoid the need for intravenous fluid. However, children with severe dehydration may need intravenous fluids.
Diet
As soon as children have received sufficient fluids and are not vomiting, they should be given an age-appropriate diet. Infants may resume breast milk or formula.
In children with chronic diarrhea, the treatment depends on the cause, but providing and maintaining adequate nutrition and monitoring for possible vitamin or mineral deficiencies are most important.
Key Points
Diarrhea is common among children.
Gastroenteritis, usually due to a virus, is the most common cause.
Children should be evaluated by a doctor if they have any warning signs (such as signs of dehydration, severe abdominal pain, fever, or blood or pus in stool).
Testing is rarely necessary when diarrhea lasts less than 2 weeks.
Dehydration is likely if diarrhea is severe or lasts a long time.
Giving fluids by mouth effectively treats dehydration in most children.
