Constipation in Kids: Should we X-ray?
Case: a 5 year old male presents with constipation.
What is your differential for constipation in kids?
First, consider AGE of the patient. Newborn, <6 months, >6 months, and pre-school aged modifies your differential.
Ensure you approach your assessment by determining whether constipation is functional, or organic.
One can use the systems framework to guide differentials for suspected organic constipation.
*List not exhaustive (1)
BOTTOM LINE: consider age, and do not assume it is functional constipation until you have completed a thorough history and physical exam.
History & Physical Exam Tips
Consider the following:
Clarify constipation definition: it is important to assess what the patient/family considers constipation to avoid over or under-diagnosis
Stool parameters: assess for large caliber stools, fecal incontinence, overflow or diarrhea (use the Bristol stool chart) (1).
Age: at onset of symptoms - newborn infants with constipation have a greater likelihood of an organic cause (1)
Dietary changes: switch to cow’s milk or weaning of breast feeding; lack of dietary fibre or fluids; food allergies?
Psychosocial: family history, social history, stressors, school entry, toilet training?
Abdominal pain: is pain relieved by defecation or not?
Systemic symptoms: weight loss/failure to thrive, hematochezia, bright red blood per rectum, fever/chills, currant jelly stools, vomiting, intermittent severe diarrhea - may indicate more serious pathology, neurological symptoms (1)
Physical exam flags: abdominal distension, fever, weight loss or failure to thrive, abnormal neurologic exam, delayed passage of meconium (>48 hours after birth), extra-intestinal symptoms (bilious vomiting, fever, ill appearance), perianal fistula, abnormal position of anus, pilonidal dimple with tuft of hair (1)
BOTTOM LINE: perform a careful history and physical examination to rule out organic causes of constipation.
Back to the case: he has had constipation on and off for about 3 months (2hard bowel movements per week, sometimes has large stools that obstruct the toilet). He lives in a stable home environment and is just entering preschool. There are no systemic signs or symptoms and he is following his growth curve. He takes no medications, and is a “picky eater.” What next?
Diagnostic Imaging: Should we order Abdominal X-ray Kids with Constipation?
Guidelines recommend against abdominal x-ray because constipation is a clinical diagnosis and does not require testing (1,2).
Abdominal X-rays are generally not very helpful for diagnosing constipation, as their accuracy is limited; subjectivity and lack of standardization result in poor sensitivity and specificity between clinicians (1,2).
Use of abdominal x-ray to diagnose constipation has been associated with increased diagnostic error (2).
If patients meet the Rome IV diagnostic criteria for functional constipation, x-ray will do little to help with management (1,2).
Rome IV Diagnostic Criteria for Functional Constipation
source (4)
Consider abdominal x-ray in the following situations:
When a rectal exam would be inappropriate (e.g., in a child with a history of trauma)
When the diagnosis remains unclear
When checking the outcome after disimpaction treatment (2)
BOTTOM LINE: Abdominal X-rays are not recommended for routine diagnosis of pediatric functional constipation, as the diagnosis is clinical based on Rome IV criteria.
Back to the case: diagnosis = functional constipation, based on the Rome IV criteria. There is no suspected organic causes (no red flags on history, normal physical exam). No further testing is needed, and we jump to treatment.
When should we refer to gastroenterology? If refractory to treatment for suspected functional constipation, or if red flags are present.
Treatment resources:
Pediatric Constipation Primary Care Pathway (Alberta Health)
McMaster Children’s Hospital constipation treatment handout
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References Mulhem E, Khondoker F, Kandiah S. Constipation in Children and Adolescents: Evaluation and Treatment. Am Fam Physician. 2022 May 1;105(5):469-478. PMID: 35559625.Simo R, Leslie A. Differential diagnosis and management of neck lumps. Surgery (Oxford). 2006 Sep 1;24(9):312-22.Choosing Wisely. Pediatric Emergency Medicine. [2022; August 20, 2025]. Available from https://choosingwiselycanada.org/recommendation/paediatric-emergency-medicine/Alberta Health. Pediatric Constipation Primary Care Pathway. [August 20, 2025]. https://www.albertahealthservices.ca/assets/about/scn/ahs-scn-dh-pathway-pediatric-constipation.pdf