Diagnosing Irritable Bowel Syndrome in Children

Irritable bowel syndrome is a condition in which contractions, or movements, in the muscular walls of the large intestine—an organ that moves digested food into the rectum—are either too strong or too weak, causing a variety of uncomfortable symptoms. The condition, commonly called IBS, tends to affect people younger than age 45, including babies and children, and is more common in girls.

The main symptoms of IBS are changes in bowel habits along with abdominal pain or cramping that goes away after having a bowel movement. For instance, a child with IBS may develop either constipation, in which stool becomes hard and dry, or diarrhea, which causes loose, wet stools. Some children experience alternating episodes of diarrhea and constipation.

Other symptoms of IBS in children include bloating, nausea, and vomiting, or a backflow of stomach acids known as reflux. Most people experience some of these symptoms on occasion, but children with IBS have them for three months or longer.

Experts don’t know for sure why some children get IBS. However, children with IBS often experience symptoms after eating certain foods or during stressful moments. Children with a family history of IBS have a higher risk of developing the condition. IBS can also be triggered by viral and bacterial infections in the gastrointestinal tract, which can lead to an overgrowth of bacteria in the intestine.

Symptoms of IBS can be similar to those of chronic inflammatory conditions of the gastrointestinal tract, collectively known as inflammatory bowel disease. Inflammatory bowel disease includes conditions such as Crohn’s disease, in which the immune system attacks tissue throughout the digestive tract.

IBS, however, is a disorder—not a disease—and does not lead to inflammation and the subsequent damage to the intestinal lining that inflammatory bowel conditions cause. Our specialists perform a physical exam and other noninvasive tests to determine which condition is causing your child’s symptoms.

Physical Exam

During a physical exam, the doctor asks if you have a family history of IBS and notes any symptoms or changes in the frequency of your child’s bowel movements and in the consistency of the stool. The doctor may also feel your child’s abdomen to determine if your child feels any pain in certain areas around the intestines.

Symptom Diary

A symptom diary is a tool that allows you and your child to recognize which foods or events may trigger IBS symptoms. These triggers may include certain foods, the time or size of a meal, or stressful events. The doctor may ask you to keep track of these in a diary for two to three weeks, which can help you to identify patterns.

Digital Rectal Exam

A doctor may perform a digital rectal exam to look for signs of IBS and to rule out other possible causes of gastrointestinal symptoms. During this exam, the doctor inserts a gloved finger into the rectum to determine if the muscles are stretched, which may occur if a child is straining frequently due to constipation.

During a digital rectal exam, the doctor also checks for blood in the stool, which may be caused by an inflammatory condition of the gastrointestinal tract, such as Crohn’s disease.

Blood Tests

Blood tests are used to look for signs of infection or inflammation. These tests measure the number of blood cells in a small sample of your child’s blood. If your child is found to have too few red blood cells, he or she may have anemia. Too many white blood cells suggest that your child may have an infection or another cause of inflammation.

Your child’s blood may also be tested for tissue transglutaminase antibodies, which are found in people with celiac disease. People with this autoimmune condition are intolerant to gluten, a group of proteins in wheat, barley, and rye. Test results are usually available in about a week.

Stool Test

A stool test can reveal the presence of bacteria or toxins produced by parasites or other organisms. Stool can also be tested for elevated white blood cell levels, which may indicate that your child has an infection or inflammation in the digestive tract. The doctor gives you a sterile container to obtain a sample of your child’s stool. Results of the test are usually available in about a week.

If there is blood in the stool or other signs of inflammation, our doctors may recommend a colonoscopy to look for signs of an inflammatory condition of the gastrointestinal tract, such as Crohn’s disease.

Breath Test

Some children with IBS are also unable to digest lactose, a sugar found in milk and other dairy products. Doctors can use a breath test to determine if your child is lactose intolerant. During this test, your child drinks a solution that contains water mixed with lactose and blows into a balloon-like bag every half hour for about two hours. The breath is then tested for the presence of hydrogen, which is produced when bacteria in the large intestine ferment undigested lactose.

If the test is positive, your child’s doctor may recommend that he or she consume lactose-free dairy products to reduce the number or severity of gastrointestinal symptoms. The breath test can also help to detect bacterial overgrowth in the digestive tract, a condition that is associated with IBS.

Our doctors perform invasive tests, such as a colonoscopy or an upper endoscopy, only if the tests above suggest that your child may have another condition that can damage the lining of the digestive tract, such as Crohn’s disease or celiac disease, or if your child’s symptoms don’t improve with treatment.