2025 – PAGE 236 – GASTROENTEROLOGY

CAUSES OF CONSTIPATION

FUNCTIONAL CONSTIPATION

Look for functional constipation in a child who has, or had, difficulty with toilet training and has had problems with frequent soiling or stool incontinence. The child may have a tendency to withhold stool.

PEARL: Diagnosis of exclusion. Look for a child with a history of soiling himself who has stool in the rectum on rectal exam. This can be differentiated from IBS by the absence of diarrhea, bloating, etc.

(DOUBLE TAKE) IRRITABLE BOWEL SYNDROME (IBS)

Irritable bowel syndrome (IBS) is a crampy abdominal pain associated with diarrhea or constipation. Symptoms may alternate. This is a diagnosis of EXCLUSION. Treat with fiber.

PEARLS: There must be some type of poop issue! There’s often an emotional component as well. Do not choose this answer unless at least some type of workup has been done already. If no workup has been done, start with noninvasive tests such as a CBC, ESR, anti-TTG, and stool guaiac. Do not choose an invasive test unless other tests are negative and the patient failed a FIBER trial. Non-invasive testing -> Fiber trial -> EGD and/or Colonoscopy.

CONGENITAL HYPOTHYROIDISM

Look for constipation + delayed anterior fontanelle closure, a hoarse cry, poor growth, or an umbilical hernia to indicate congenital hypothyroidism.

CYSTIC FIBROSIS (CF)

Cystic fibrosis (CF) should be top on your list for any newborn who does not produce stool within 48 hours!

HIRSCHSPRUNG DISEASE

Hirschsprung Disease results in constipation early in infancy and tends to present prior to 2 years of age. There are no problems with soiling. It can be associated with poor oral intake, abdominal distension, occasional diarrhea, and bilious emesis. It may present as FTT. Boys are more often affected. Patients have an aganglionic (lack of parasympathetic innervation) segment of bowel that is narrow or contracted, and can eventually result in megacolon proximal to that segment. There are strong associations with DOWN SYNDROME and CYSTIC FIBROSIS. Diagnosis is by biopsy.

PEARLS: Look for early history of constipation, delayed passage of meconium, an absence of fecal incontinence, and the ABSENCE of stool in the rectum on rectal exam. The “squirt sign” or “blast sign” is the explosive release of gas and stool after the digital rectal exam. Also keep in mind the associations with Trisomy 21 (constipation + syndromic features) and CF patients (constipation + foul-smelling stools). If you are presented with images, remember that the narrow segment of the bowel (next to normal or dilated bowel) is the affected/aganglionic segment.

IMAGE: www.pbrlinks.com/HIRSCHSPRUNG1
IMAGE: www.pbrlinks.com/HIRSCHSPRUNG2

MECONIUM ILEUS

Meconium ileus results in abdominal distension and vomiting after birth. It’s due to thickened meconium causing an obstruction in the ileum. You may find palpable bowel cords on exam. X-ray may show ground glass or “soap and bubble” stool, calcifications, or air-fluid levels. Contrast enema may show a microcolon (small from the splenic flexure to the anus). There may be dry meconium pellets in the small intestine.

PEARLS: Meconium ileus is often the presenting symptom of CYSTIC FIBROSIS.