If your child has mild constipation that is readily resolved with dietary changes, prune juice, a rectal thermometer, or over-the-counter treatments, no tests need to be done.
However, if the constipation is not easily treatable, or if it worsens despite attempts to treat it, tests should be done. An X ray can show how much stool remains in the intestine. It can also identify structural abnormalities of the intestinal tract.
More invasive tests, such as colonoscopy or biopsy, can be done as well. These are not common but are sometimes helpful in chronic cases. Gastroenterologists are doctors who specialize in the intestinal tract and are trained to perform these tests. Again, it is unusual for constipated toddlers to require such invasive tests.
Very occasionally, blood tests are done to determine whether there might be an underlying cause of the constipation. These include tests to assess thyroid function, calcium level, lead level, and celiac disease antibodies. Abnormalities in any of these areas can point toward the source of chronic constipation.
In extreme cases, an MRI may be considered. This test can look at the structures and nerves around the intestine. Ongoing or particularly severe constipation can be caused by a mass pushing against the intestine and blocking normal flow. It also may be a result of inadequate nervous system input to the intestine.
Hirschsprung’s disease is the absence of nerves at the end of the colon. These nerves are necessary to help keep the bowels moving, so without them, severe constipation will result. This uncommon problem can be diagnosed only by biopsy, and treatment requires surgery.
A tethered cord is an anomaly along the spinal cord that sometimes causes constipation. The nerves traveling from the spinal cord to the bowel become entrapped or inflamed, interfering with their ability to function properly.
What are the treatments?
There are two routes to treat constipation: from the top (through the mouth) and from the bottom (up the rectum).
Stool softeners are taken by mouth. They pass through the stomach into the intestine, helping to soften the forming stool by creasing its water content. Prune and pear juice work as stool softeners, as do corn syrup and mineral oil. Prescription stool softeners are available as well. Lactulose is a nonabsorbable sugar that draws water into the colon quickly. Other stool softeners include milk of magnesia and docusate (Colace).
To treat your child from the bottom end, you can use a suppository or enema. These treatments provide anal lubrication and stimulate the rectum to contract at the same time. The stimulation helps move the bowels. Glycerin suppositories (sized for children) are semisolid, so they dissolve quickly once in the anus. Enemas are liquids that are squirted into the anus.
Do not use anal stimulation regularly without speaking with your doctor. You do not want your child to become dependent on this as a means of moving her bowels. Furthermore, as almost any toddler will tell you, this is not the preferred method of treatment.