What Causes Constipation?

Patient Presentation
A 4-year-old female came to clinic with a history of not passing stools for 6 days. She had been traveling and her mother said she refused to use the toilet because she was afraid she was going to fall into it. Her appetite had decreased in the past 48 hours and she complained of more generalized abdominal pain. Her mother had tried to give her a suppository, but said, “That didn’t go very well.” The past medical history was positive for intermittent constipation that normally resolved with increased fluids and prunes. The family history was non-contributory.

The pertinent physical exam showed a healthy appearing female with normal vital signs and growth parameters.
Her abdominal examination revealed a moderately distended abdomen with increased abdominal sounds and palpable stool. Her genitourinary, spine and neurological examinations were normal. The diagnosis of constipation was made. As the child and parent were reluctant to use any rectal medication, MiralaxTM at ~2 mg/kg/day was ordered for 3-4 days to produce diarrhea. Then the mother was instructed to decrease the amount to ~ 1 mg/kg/day for the next 3 days and further instructions to titrate the medication off. One week later the patient returned to clinic for upper respiratory symptoms and the mother said the Miralax had resolved the constipation.

Constipation generally is defined as infrequent or painful defecation. Constipation can be very disturbing to the patient and family who believe the stools are too infrequent, too hard or too difficult to pass. Most children develop constipation after the child begins to associate pain (e.g. a hard bowel movement) with defecation. The child then begins to withhold the stools trying to decrease the defecation discomfort. As stool withholding continues, the rectum dilates and gradually accommodates with the normal defecation urge disappearing. Passing large hard stools infrequently reinforces the defecation pain. The cycle continues. If the cycling is severe enough, worsening stool retention and more abnormal defecation dynamics occurs. Chronic rectal distension results in both loss of rectal sensitivity, and loss of urge to defecate, which can lead to encopresis.

Treatment basics include:

  • Evacuate the colon – a clean out by enemas or oral medication
  • Stop painful defecation – by using laxatives in a maintenance regimen so patients have a soft stool daily
  • Establish regular bowel habits – through toilet sitting

A balanced diet is important and increasing dietary fiber may also help.
Medications include osmotic laxatives, stimulant laxatives, stool softeners and lubricants.
MiraLaxTM is polyethylene glycol, is an osmotic laxative, and pool research studies show that it may be superior to placebo, milk of magnesia or lactulose. It is usually used as a maintenance medication in a dose of 0.5 -1 gram/kg/day divided BID. The dose can be titrated to have one soft stool per day.

Usually primary care providers can successfully treat constipation.
A pediatric gastroenterology consultation may be considered for treatment failure, complex disease management or concerns for organic disease as the etiology.

Learning Point
The differential diagnosis of constipation includes:

  • Nonorganic (most common)
    • Situational – poor toilet training techniques (coercive, excessive, etc.), toilet phobia, school/public bathroom avoidance including travel,
      sexual abuse

    • Abnormal stool dryness and/or volume – dehydration, decreased dietary fiber, eating disorders, malnutrition or underfeeding,
    • Constitutional – colonic inertia, genetic predisposition
    • Depression or other psychiatric conditions
    • Developmental – attention or cognitive disorders
  • Organic
    • Anatomic malformations – anal abnormalities (i.e. stenosis, imperforate, anteriorly displaced)
    • Gastrointestinal or metabolic problems – hypothyroidism, hypercalcemia, hypokalemia, Crohn’s disease, cystic fibrosis, diabetes mellitus, multiple endocrine neoplasia, gluten enteropathy
    • Central nervous system – spinal cord (i.e. anomalies, trauma, and tethered cord), encephalopathy, Hirschsprung disease, intestinal neuronal dysplasias, neurofibromatosis, visceral myopathies or neuropathies
    • Abdominal musculature abnormalities – Down syndrome, gastroschisis, prune belly
    • Connective tissue disease – Ehlers-Danlos syndrome, scleroderma, systemic lupus erythematosus
    • Drugs – opiates, antacids, anticholinergics, antidepressants, antihypertensives, phenobarbital, sucralfate, sympatomimetics
    • Skin abnormalities – Group A streptococcus perianal skin infection, Lichen sclerosis et atrophicus
    • Tumor – pelvic or other abdominal tumor
    • Other – Botulism, Cow’s mild protein intolerance, lead and heavy metal toxicity, Vitamin D intoxication

Questions for Further Discussion
1. What physical examination findings should be highlighted during an evaluation for constipation?
2. What history questions should be highlighted during an evaluation for constipation?
3. What are indications for surgical consultation in a child with constipation?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for this topic: Constipation.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

Constipation Guideline Committee of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition. Evaluation and treatment of constipation in infants and children: recommendations of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition. J Pediatr Gastroenterol Nutr. 2006;43(3):e1-e13.

Burgers R, Di Lorenzo C. Diagnostic testing in constipation: is it necessary? J Pediatr Gastroenterol Nutr. 2011 Dec;53 Suppl 2:S49-51.

Gordon M, Naidoo K, Akobeng AK, Thomas AG. Osmotic and stimulant laxatives for the management of childhood constipation. Cochrane Database Syst Rev. 2012 Jul 11;7:CD009118.

ACGME Competencies Highlighted by Case

  • Patient Care
    1. When interacting with patients and their families, the health care professional communicates effectively and demonstrates caring and respectful behaviors.
    2. Essential and accurate information about the patients’ is gathered.
    4. Patient management plans are developed and carried out.
    5. Patients and their families are counseled and educated.

  • Medical Knowledge
    10. An investigatory and analytic thinking approach to the clinical situation is demonstrated.
    11. Basic and clinically supportive sciences appropriate to their discipline are known and applied.

  • Systems Based Practice
    23. Differing types of medical practice and delivery systems including methods of controlling health care costs and allocating resources are known.
    24. Cost-effective health care and resource allocation that does not compromise quality of care is practiced.


    Donna M. D’Alessandro, MD
    Professor of Pediatrics, University of Iowa Children’s Hospital