Constipation can be defined as condition in which the bowel movements occur less frequently than usual or stools tend to be hard, painful and difficult to pass. Any definition of constipation depends upon the usual pattern and consistency of a child’s stools. It can affect up to 10% of children at any given time.
The first bowel movement usually occurs within 36 hours after birth in term babies (babies born within two weeks of their expected due date). Regular or normal bowel movements can vary significantly among children, especially among infants. Breast fed infants usually have more frequent bowel movements than formula fed babies. Bowel movements tend to become firmer and less frequent in infants following the introduction of “solid” (i.e., non-formula) foods in their diet.
Most children have between 3 bowel movements per day to 3 bowel movements per week.
Any change in a child’s normal routine including a change in diet, a change in activity level or a different bathroom can cause constipation. Although it can start without any clear cause, there are certain times when a child is more likely to become constipated:
Whenever bowel movements become hard, passing them becomes a painful and unpleasant experience. The child then usually tries to avoid passing bowel movements by holding them; this is also know as witholding. This may eventually lead to larger, harder stools that worsen the situation. The children may cross their legs, stand on toes, or squeeze their buttocks together to try to avoid passing a bowel movement. Many times parents misinterpret these behaviors as straining to pass stools when in reality the children are trying not to have a bowel movement. These behaviors are called retentive withholding.
It is slightly more common in boys than girls. About 25-50% of children with constipation will have a family member with similar problems. Children whose development is delayed and those born with problems affecting the anus or rectum are more likely to suffer from chronic constipation. Children with behavioral issues such as attention deficit hyperactivity disorder may also have a higher chance of being constipated.
Constipation may be associated with stomachaches or pain in other parts of the abdomen. Constipation can result in tears of the anus called anal fissures. These tears cause blood in the bowel movements. Because stools may be painful to pass over an anal tear, children who have these tears may develop withholding behavior as described above. Withholding can result in chronic constipation, soiling of the underwear with stool and even difficulty walking. Soiling is usually an indication of rectal impaction with stool. It often occurs when the child is relaxed such as in a warm bathtub or sleeping and is not withholding. Soft, ‘clay-like’ stool then leaks around the ball of impacted stool in the rectum. Children who are withholding their bowel movements often have a decreased appetite and activity level.
In over 90% of children, constipation is not associated with other diseases. There are however certain “red flags” or worrisome characteristics that should alert the physician that another underlying disease should be considered and tested for. Diseases that can have constipation as one of their symptoms include:
Constipation can also be a side effect of a medicine that the child is taking for another condition.
If constipation does not go away or does not get better after the treatment that your pediatrician prescribes, seeing a pediatric gastroenterologist can be helpful. These specialists will obtain a detailed history and perform a physical examination to distinguish constipation that is due to withholding behavior from constipation due to an underlying disease. While most children do not need any tests, your physician is the best judge to decide which test if any is necessary and to provide the most information about the cause of your child’s constipation.
Your doctor may suggest one or more of the following special tests for constipation:
Plain x-ray of the abdomen (also known as a KUB)
This is a single or set of x-rays that can give your physician a rough idea if there is a lot of stool present. It may also indicate if the colon is dilated. This type of x-ray is also obtained prior to a barium enema which is described below.
Anorectal manometry or motility test
This test determines if the nerves and muscles responsible for passing a bowel movement are working together. It is performed by inserting a very small balloon at the end of a catheter into the rectum and blowing up the balloon. The response to inflating the balloon determines if the nerves and muscles are working together properly. Relaxation of the anal muscles, known as the anal sphincter, after inflation of the balloon should occur.
This is an x-ray test where barium or another type of contrast is inserted via a catheter into the rectum and x-rays of the abdomen are taken. The test may or may not require a special bowel preparation to clean out the bowel before the test. This test is used to diagnose a blockage in the intestine or an area that may be narrowed or abnormal. It is also used in the diagnosis of Hirschsprung’s disease.
This is a test where a small (pinch) biopsy is performed from the lining of the rectum to determine if normal nerve cells are present in its walls. The sample of tissue that is obtained is examined under the microscope looking for ganglion cells, which are special nerve cells. If they are absent then the diagnosis of Hirschsprung’s disease is made.
Transit study or marker study
This test is performed to determine if the reason for constipation is due to slow movement throughout the colon or just in the last part of the colon known as the rectum. Plastic markers, which can be seen on x-ray, are swallowed and then several x-rays are performed over the next 4-7 days to determine how long it takes them to pass through the GI tract. Patients with normal motility pass the majority (>80%) of the markers within 5 days. If the markers are not passed but are found to remain throughout the colon, this suggests slow transit of the entire colon. If the markers do not pass and are clustered in the rectum, this may indicate a problem in the rectum only.
This is an endoscopy of the lower GI tract. This test is usually not indicated for the evaluation of routine constipation in children. This test may be helpful if children have blood in their bowel movements not due to a fissure or straining or other concerns on history or physical exam to suggest inflammatory bowel disease and is also used for placing a colonic manometry catheter if necessary (see below).
This is a specialized test done in children who have continued problems with intractable constipation despite adequate medical therapy. It involves placing a catheter at the time of colonoscopy to determine whether there are normal contractions in all parts of the colon. The test requires a period of prolonged monitoring of the contractions of the colon after placement of the catheter. This test is used to establish the diagnosis of colonic pseudo-obstruction in children, a very rare condition.
The best way to treat constipation is a combination of education, behavioral modification, dietary modification and non-habit forming medications. If there is an impaction of stool, which means a very large amount of stool in the rectum, it needs to be evacuated first either by an enema or by a medication given by mouth. Patients are then started on a maintenance medication for a few months to soften the stools, and a program of bowel retraining is started. The child is advised to sit on the potty after every major meal for 5-10 minutes and try to have a bowel movement. Positive reinforcement (reward) is provided if the child has a stool in the potty. Behavioral modification may be needed in some patients. Some children, especially boys, tend to get so involved in sports or playing video or computer games that they ignore the ‘urge’ to have a bowel movement. Postponing the event makes things worse in the long run. The goal of treatment is to make having a bowel movement pain free for the child by softening the stools. Consistency in treatment is crucial for success. This can be frustrating for the child as well as the parent. Punishment is discouraged because it reinforces a negative association with stooling.
Dietary and lifestyle changes may be helpful in improving a patient’s symptoms. Increasing dietary fiber over 1 to 2 weeks is often helpful, by increasing bulk that then stimulates colon contractions. This strategy may take a while to work and in some cases of severe constipation may make symptoms temporarily worse.
High fiber foods include:
Fiber supplements are available if parents find their children will not eat more fiber in their diet. There is little information to recommend one product over another. A patient may have to try several before finding one that is acceptable and that they are willing to take regularly. Fiber supplements are given two times a day and must be taken with a sufficient amount of water. Some patients may notice increased passage of gas while on fiber supplements. It is essential to increase the amount of free water in the diet as well for children with constipation except for infants in whom water intoxication may occur. Consultation with a pediatric dietitian may help guide parents as to the correct amount of fluid intake and fiber intake for their child. Increasing a patient’s physical activity is also helpful to promote regular bowel movements.
If constipation does not get better with dietary and behavior modifications, stool softeners are indicated. The two most common stool softeners used in children are polyethylene glycol 3350 and lactulose.
Polyethylene glycol has become the most widely used medication for treating constipation in children. It is a white powder that can be dissolved in juice, water or other liquids and does not get absorbed by the body. It is tasteless, safe and non-habit forming. Children have soft, more frequent stools on this medication.
Lactulose is a prescription laxative that is made of a sugar that is not absorbed by the intestines. It works by pulling water into the bowel movements that helps to keep them soft. Because it is not absorbed, lactulose is not associated with side effects except for increased gassiness and diarrhea if the dose of the medicine is too high. Lactulose is not a stimulant and therefore the bowel does not become dependent on it.
Milk of Magnesia is a mild stimulant laxative that may be used at bedtime in children with mild constipation. It is available over the counter without a prescription. The major limiting factor in its use in children is its taste, even though it is now available in different flavors.
Mineral oil, which is given mixed with juice or milk, acts as a lubricant to allow bowel movements to pass easier. This type of medication is particularly useful in toddlers who withhold their bowel movements. Older children may have leakage of the oil in their underwear that may not be acceptable. This problem usually goes away with decreasing the dose of mineral oil. Mineral oil should not be given to children with neurologic problems who are at high risk for aspiration. Flavored forms of mineral oil are also available.
Stimulant laxatives, such as senna or bisacodyl, that cause the colon to have strong contractions, are not popular with pediatricians or pediatric gastroenterologists due to the concerns that they may damage the intestinal nerves if given over prolonged periods and that patients may become dependent on them for stool passage.
Surgery is rarely needed for constipation. The exception to this is Hirschsprung’s disease, which is treated with surgical removal of the portion of the bowel where there are no normal nerves. Also, there are rare cases when children develop a dilated and floppy colon that has no normal contractions, a condition called pseudo-obstruction. These children also may benefit from removing the affected colon surgically. Recently special surgical procedures, such as cecostomy or appendicostomy placement (creating an opening between the bowel and skin which allows administration of enemas “from above” rather than from below via the rectum), have been devised to help children with spinal cord and other neurologic abnormalities that have severe problems with constipation.
Marsha H. Kay, MD, FACG, The Cleveland Clinic, Cleveland, OH, and Annette E. Whitney, MD, Digestive Health Associates of Texas, Dallas, TX, – Updated December 2012.
Marsha H. Kay, MD, The Cleveland Clinic, Cleveland, OH, and Vasundhara Tolia, MD, Children's Hospital of Michigan, Detroit, MI – Published September 2004.