Exams and Tests for Encopresis
To diagnose enopresis, your child’s health care provider will ask many questions about his medical history, toilet training history, diet, lifestyle, habits, medications, and behavior. A thorough physical exam will be done to assess the child’s general health as well as the status of the colon, rectum, and anus. The examiner may insert a gloved finger into the child’s rectum to feel for stool and make sure the anal opening and rectum are of normal size and that the anal muscles are of normal strength.
In most cases, blood tests are not part of the evaluation of constipation and/or encopresis. In some cases, an X-ray of the child’s abdomen or pelvis is performed to determine how much stool is present in the colon and assess if the colon and rectum are enlarged. Occasionally, a barium enema is performed. This is a special type of X-ray. A small tube is inserted into the child’s rectum, and the colon is slowly filled with a radiopaque dye (barium). X-rays are taken throughout the procedure to see if areas of narrowing, twisting, or kinking in the lower intestine are causing the child’s symptoms.
In some cases, anorectal manometry may be performed. With this test, a small tube is inserted into the child’s rectum. The tube has several pressure sensors in it. During the test, the doctor can determine how the child is using his or her abdominal, pelvic, and anal muscles during defecation. Many children who have chronic constipation and/or encopresis do not use their muscles in a coordinated fashion during bowel movements.
The main objective of manometry is to confirm increased pressure within the anus. Manometry can also show whether the nerves controlling the anal sphincter, anus, and rectum are present and working by measuring reflexes in this area. Manometry can measure how far the rectum is distended and whether sensation in this area is normal. Abnormal contractions of the muscles in the pelvic floor can be documented by using manometry.
Anorectal manometry can also be helpful to rule out Hirschsprung disease, a very rare cause of constipation without encopresis. If Hirschsprung disease is seriously considered as a cause of your child’s encopresis, a biopsy of the rectum may be necessary. A biopsy is the removal of a very tiny piece of tissue for examination under a microscope. This is done to look for the absence of nerve function in the rectum, a characteristic sign of Hirschsprung disease.