By Howard J. Bennett, MD

A 9-year-old girl arrived in my office complaining of a stomachache. Over the past twelve months, she had come in numerous times with abdominal distress. Some of the visits were accompanied with a sore throat, which suggested the problem might be due to a strep infection. Other times, she had diarrhea, which suggested the pain was caused by the “stomach flu.” But for most of the visits, there was nothing in the medical history that suggested why her tummy hurt.

At one point, her mom asked me if something else might be causing her symptoms. I got a more detailed medical history and asked her mom to keep a diary of the pain. The diary included when she had the pain, how much it hurt and how long it lasted. I asked her mom to keep track of what she ate, how often she pooped and what her bowel movements looked like. I also did some lab tests to eliminate serious causes of abdominal pain.

The girl’s blood, urine and stool tests were normal, and her diet was not contributing to the pain. However, when I looked at the pattern of her pain, it became clear that it was due to stress she was experiencing at school. Once she was able to talk about the stress, her pain subsided considerably.

The Problem

Stomachaches account for numerous visits to pediatricians’ offices. Parents often worry that a kidney infection or appendicitis is responsible for the pain. Although serious disorders can cause abdominal pain, the problem is usually due to something less worrisome.

Abdominal pain can be broadly divided into two types. Acute pain has been present for less than a week. It can come on suddenly or it can build slowly over the course of a day. Pediatricians see children with this type of pain every day. Recurrent pain, on the other hand, has been present for a period of weeks, months or years. Ten to fifteen percent of school-aged children will seek medical care for recurrent abdominal pain.

Most cases of recurrent abdominal pain are caused by stress, constipation or lactose intolerance. Diets that include lots of foods with high-fructose corn syrup bother some children. Some drugs, such as ibuprofen, can cause abdominal pain, though it occurs less often in children than adults. More serious causes of recurrent abdominal pain, such as celiac disease, ulcerative colitis and Crohn’s disease, are much less common in a general pediatric setting.

Making a diagnosis

When doctors see children with recurrent pain, they start with a detailed medical history because that often suggests a diagnosis. For example, it is important for parents to check the frequency and consistency of a child’s bowel movements because adults are usually unaware of what goes on in the bathroom after their children are toilet trained.

Pain that occurs more often during the week than on weekends or holidays is likely to have a stress component. However, weekends are not necessarily stress-free. Children may still have to deal with sports, religious school or family issues such as parental separation or divorce.

Although doctors are usually less concerned about pain that is mild, the intensity does not always correlate with the diagnosis. The following symptoms increase the chances that a serious problem could be causing the pain:

• The child has recurrent vomiting, diarrhea, weight loss or appears ill.
• The pain awakens the child from sleep.
• The pain is not located in the middle of the abdomen, i.e., around the belly button.

If a doctor is concerned that a serious condition might be causing a child’s symptoms, he will often obtain blood, urine, and stool tests as well as an abdominal x-ray and sonogram. In difficult cases, the child may be referred to a specialist for further evaluation.

But most of the time, the stomachaches that bring a child to the doctor’s office can be handled with a few changes to diet or routine.

Lactose Intolerance

Lactose is the sugar found in milk, cheese, yogurt and other dairy products. Lactase, the chemical that is needed to digest lactose, is made in the upper part of the small intestine, but some people don’t make it.

If a person doesn’t make lactase, any lactose he eats or drinks will pass into the large intestine. Once lactose enters the large intestine the bacteria that live there consume it and release byproducts that can make a person feel sick. Symptoms of lactose intolerance include some or all of the following: nausea, stomachache, belching, loose bowel movements and excessive gas.

Lactose intolerance is not an all-or-nothing phenomenon. Some people are mildly lactose intolerant and can handle small amounts of lactose (see sidebar below). Other people are completely intolerant and any amount of lactose will make them sick.

Lactose intolerance varies between ethnic groups. It is less common in people of Northern and Eastern European descent and more common in people from South American, Africa and Asia.

If a person catches an intestinal virus with vomiting and diarrhea, he may become temporarily lactose intolerant. That’s why doctors commonly recommend a milk-free diet for a few days after someone gets the “stomach flu.”

Lactose intolerance can be diagnosed with a procedure called the hydrogen breath test. This test usually requires a visit to a gastroenterologist’s office so most pediatricians make the diagnosis by determining if a child’s symptoms resolve when lactose is removed from the diet. This could take a week or more to figure out because the symptoms of lactose intolerance can be intermittent and do not always occur immediately after someone ingests milk products.

The best way to treat lactose intolerance is to avoid milk sugar. Most people do this by drinking lactose-free milk or taking lactase supplements before they ingest milk products. Another option would be to consume products made from non-milk sources such as soy, rice or almonds.

Constipation

I have been a pediatrician for more than 25 years, and three things continue to surprise me. First, large numbers of people suffer from constipation. According to Dr. Benny Kerzner, emeritus chief of pediatric gastroenterology at Children’s National Medical Center, one in four new patient referrals to specialists like him are for constipation. Second, most people do not realize that constipation is a common cause of abdominal pain. Third, constipation manifests itself in unsuspecting ways.

People with constipation may pass large, hard bowel movements once or twice a week or lots of small “rabbit pellets” every day. Some people experience constipation regularly while others have it once in a while. Some people with constipation have no symptoms other than having to work hard to push out a large bowel movement. Others may feel bloated or have a stomachache for days before they go. Constipation can come on gradually or so suddenly a person may double over in pain. It is not uncommon for parents to rush their child to an emergency room because they thought the pain was due to appendicitis.

In order to appreciate how constipation causes abdominal pain, it helps to know something about digestion. Food begins its journey through the intestinal tract the moment it enters the mouth. When a person chews, saliva is released to soften food and make it easier to swallow. The next stops are the stomach and small intestine where acid, chemicals and lots of water are used to digest food and facilitate the absorption of microscopic nutrients into the bloodstream.

The soupy material that enters the large intestine is made up of waste and water that was used in the digestive process. The main purpose of the large intestine is to reabsorb this water. If a person develops diarrhea from an intestinal virus, the large intestine becomes “sick” and cannot reabsorb water properly. That is why diarrhea varies from a yogurt-like to watery consistency.

Peristalsis is the term that describes how food and waste are pushed through the intestinal tract. This takes place because muscles in the intestine contract and relax in a coordinated fashion. If you visualize “the wave” that occurs at sporting events, you will have a good idea how peristalsis works.

The main reason people become constipated is because waste moves through their large intestine slowly. This allows more water to be reabsorbed, which results in firmer bowel movements. If a person experiences pain with constipation, it’s because the large intestine has to work harder to push dense fecal material toward the anus.

Very few medical conditions that cause constipation in children. Most of the time, it occurs because of dietary factors, insufficient water intake or because the problem runs in the family.

The most common foods that cause constipation are milk products and processed grains (white bread, pasta, rice). Some people have problems if they eat apples and bananas, though many nutrition experts say only unripe bananas cause constipation.

The best way to manage constipation is to do the following:

• Eat fewer foods that can cause constipation.
• Eat more foods that are high in fiber.
• Drink plenty of water.
• Get lots of exercise.
• Listen to the body when it is time to defecate. (If a child puts off going to the bathroom, his bowel movements will become harder and more difficult to pass.)

Changing a child’s diet and toileting behavior frequently resolves constipation. In some cases, parents can achieve success by cutting back on constipating foods rather than asking children to eat foods they do not like. If altering the diet does not work, there are a number of medications that can help. These medicines are divided into two groups: laxatives and stool softeners. Laxatives stimulate intestinal peristalsis, which helps propel bowel movements through the body. Stool softeners hold water within the intestinal tract, thereby making it easier to pass a stool. Parents should talk to their doctor before using any medication.

Stress

Everyone has to deal with stress. Fortunately, people and animals are equipped with the tools they need to fight or run away depending on which strategy is most likely to succeed. This process is called the fight-or-flight response. However, this response does not only kick in when some extremely dangerous situation is imminent.

The day-to-day stress that people deal with (worrying about paying bills or interacting with peers at school) can trigger a variation of this response. It is less intense, but lasts longer. And the same biologic responses that would give a person extra strength in dangerous situations can produce physical symptoms when facing ordinary stress: rapid heart rate, feeling tense, nervous or queasy, stomachache and having sweaty palms.

A good way to explain this phenomenon to children is to ask them if they’ve ever gotten “butterflies” in their stomach before a soccer game or when they had to speak in front of their classmates. (See, “Ever wondered why you get butterflies in your stomach,” LINK: https://howardjbennett.com/kidspost-articles/why-you-get-butterflies-in-your-stomach/ .)

Stress causes abdominal pain when the nerves in a person’s intestinal tract overreact to the normal process of digesting food and pushing waste out of the body. Two additional facts are important regarding stress-induced abdominal pain. First, the situation that causes the stress does not always occur at the same time the person is having pain. Second, even though stress is the trigger, the pain is very real.

Dealing with stress-induced abdominal pain is trickier than managing constipation or lactose intolerance. In general, eating a healthful diet is important, and in some people, taking probiotics can help reduce pain. Two additional steps can help.

• Turn off the fight-or-flight response (see sidebar below).
• Try to figure out where the stress is coming from by talking to your child about school, friends, home, etc. Talk to your doctor for guidance on how to address the problem.

Conclusion

In most cases, children can manage recurrent abdominal pain with the help of their parents and a thorough medical evaluation to determine what factors are causing the symptoms. In some cases, referral to a specialist is indicated. Pediatric gastroenterologists are experts at diagnosing recurrent abdominal pain. Mental health therapists can be very helpful for children with stress-induced abdominal pain that does not respond to the suggestions provided by their doctors.

© 2012 Howard J. Bennett. All Rights Reserved.

 (This article was originally published in the Washington Post, October 2012.)

For more articles and other information, please visit Dr. B’s website at http://www.howardjbennett.com