Approach to constipation (pediatrics): Clinical sciences

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Introduction0:00–0:36

Constipation refers to an abnormal stooling pattern that's associated with hard stools and incomplete, infrequent, or painful defecation.
The stooling pattern in healthy infants is highly variable, but when constipation occurs it suggests a pathologic condition.
On the flip side, by 4 years of age, most healthy children pass one normally formed stool daily or every other day. Constipation in this age group is more likely to represent a functional gastrointestinal or GI disorder.

H&P0:36–1:37

Now, if a pediatric patient presents with constipation, you should first obtain a focused history and physical examination.
These patients or their caregivers typically report infrequent bowel movements, straining during defecation, and hard stool consistency.
Meanwhile, the physical exam may demonstrate mild abdominal distension, a palpable stool mass in the lower abdomen, or an anal fissure.
These findings confirm a diagnosis of constipation. Now, here’s a clinical pearl!
As part of your diagnostic workup, you can also perform a digital rectal exam to assess for impacted stool in the rectal vault.
However, because it’s uncomfortable and invasive, many practitioners only perform this exam when alarm symptoms are present or when the diagnosis is unclear.
Okay, now that you know your patient has constipation, your next step is to assess their age and proceed with your diagnostic workup.
Let’s start by discussing constipation in newborns. In this age group, it’s essential to assess the timing of meconium passage.

Newborns1:37–1:48

If your patient has not passed meconium within 48 hours of birth, examine your patient to assess anal patency. Let’s start with abnormal exam findings.

Failure to Pass Meconium1:48–1:54

Anorectal Malformation1:54–2:48

If your patient has an imperforate anus, meaning you cannot identify an anal opening; or if the anal opening appears stenotic or anteriorly displaced, diagnose constipation due to an anorectal malformation.
Time for a clinical pearl! Imperforate anus often occurs in combination with other congenital anomalies, as part of the VACTERL association; so be sure to look for anatomic anomalies involving the: Vertebrae, Anus, Cardiac structures, Trachea, Esophagus, Renal system, and Limbs.
Now, let’s say the exam reveals a patent anus with normal anatomy. In this case, consider conditions that cause intestinal obstruction, like meconium ileus and Hirschsprung disease; and order an abdominal X-ray.
In some cases, the X-ray might show dilated loops of small bowel with a bubbly appearance which represents meconium that's mixed with air, sometimes referred to as “soap bubble” or “ground glass” appearance.

Meconium Ileus2:48–3:29

If you see it, consider meconium ileus and order a contrast enema. The presence of a microcolon with a dilated proximal bowel confirms meconium ileus, a condition in which hyperviscous meconium sticks to the small bowel wall and obstructs the terminal ileum.
The majority of newborns with meconium ileus have cystic fibrosis, so remember to order a sweat chloride test for patients who fail to pass meconium within 48 hours of birth.

Hirschprung Disease3:29–4:19

Okay, let’s go back to X-ray findings. If the radiograph demonstrates dilated proximal bowel loops and decreased or absent air in the distal segment of the colon; consider Hirschsprung disease.
Then, obtain a contrast enema and consider a rectal suction biopsy. In Hirschsprung disease, the enema typically shows a funnel-shaped transition zone between the dilated proximal colon and a narrow distal segment.
If you obtain a biopsy, it will reveal an absence of ganglion cells in the colonic submucosa. With these findings, diagnose Hirschsprung disease.
Also remember that Hirschsprung disease commonly occurs in patients with Down syndrome, so keep a high index of suspicion in these patients, especially if they also have bilious vomiting, abdominal distension.
Now, let’s go back and consider infants who have passed meconium within 48 hours of birth. Your next steps are to assess your patient’s sacral anatomy and perform a neurologic exam.

Meconium Passed4:19–4:26

Spinal Cord Abnormality4:26–5:31

The exam might reveal a sacral dimple; a tuft of hair or pigmentation over the lower spine; as well as an absent anal wink or decreased lower extremity reflexes.
These findings should make you consider the possibility of a spinal cord abnormality and obtain an MRI of the spine. Imaging may demonstrate a meningomyelocele, a tethered spinal cord, or a spinal cord tumor; any of which confirms the presence of a spinal cord abnormality.
Here’s another clinical pearl! Infant dyschezia, which is also called grunting baby syndrome, is a common and benign phenomenon that caregivers frequently mistake for constipation.
Infants with dyschezia experience recurrent, brief episodes of crying, straining, and facial redness; during which they pull their knees up to their chests before passing a soft stool.
These infants are otherwise healthy and well-appearing, and symptoms usually resolve spontaneously within a month. Okay, let’s switch gears and discuss constipation in older infants and children.

Infant/Child5:31–5:58

Start by assessing for an exposure to medications or toxins associated with constipation, such as opioids, antacids, iron supplements, or lead.
If your patient or their caregiver reports a known or suspected exposure, you can attribute your patient’s constipation to a medication or toxin effect.
However, if your patient has no known or suspected medication or toxin exposure, you should consider organic causes of constipation, like thyroid dysfunction or celiac disease.

Organic Causes5:58–6:12

Hypothyroidism6:12–6:36

First, assess for signs and symptoms suggesting thyroid dysfunction. If your patient’s history includes fatigue, weight gain, cold intolerance, and brittle nails or hair; and the exam reveals a goiter; consider hypothyroidism.
To evaluate further, order a TSH and a free T4. An elevated TSH with a decreased free T4 confirms hypothyroidism.

Celiac Disease6:36–7:51

Now, if there are no signs and symptoms suggesting thyroid dysfunction, your next step is to assess for signs and symptoms of celiac disease.
In this case, your patient may have a history of an autoimmune condition like type 1 diabetes mellitus; or they may report abdominal bloating.
The exam may reveal short stature, pallor, or dermatitis herpetiformis, which is a chronic, pruritic, blistering rash. The presence of these findings should make you consider celiac disease.
To evaluate further, obtain labs, including an anti-tissue transglutaminase immunoglobulin A, or anti-tTG IgA; and total IgA levels.
A positive anti-tTG IgA and normal total IgA are highly suggestive of celiac disease. To confirm the diagnosis, you can order an upper endoscopy with duodenal biopsy.
Here’s another clinical pearl! Metabolic disturbances such as hypokalemia and hypercalcemia can also cause transient constipation.
Likewise, conditions like diabetes insipidus and diabetic ketoacidosis can cause dehydration that, if left untreated, can lead to constipation.

Functional Causes7:51–8:40

Now, if your patient has no signs or symptoms of celiac disease, consider functional gastrointestinal disorders, like irritable bowel syndrome and functional constipation.
These are diagnoses of exclusion, which means you must first rule out organic causes. To evaluate for irritable bowel syndrome with constipation, or IBS-C, start by assessing the Rome IV criteria.
These include recurrent abdominal pain at least 4 days per month during the past 2 months, plus 1 or more of the following: abdominal pain related to defecation; a change in stool frequency; or change in stool appearance, with firm, hard stools.
Additionally, the abdominal pain must persist after the constipation resolves. If these criteria are met, diagnose IBS-C.

IBS-C8:40–8:44

Functional Constipation8:44–10:20

However, if your patient does not meet the Rome IV criteria for IBS-C, assess the Rome IV criteria for functional constipation.
These include 2 or more of the following, occurring at least once per week for 1 month: 2 or fewer defecations per week; stool retention or fecal incontinence; painful, hard bowel movements; a large fecal mass in the rectum; retentive posturing; and large-diameter stools that are difficult to flush.
If your patient meets these criteria, diagnose functional constipation. This condition is the most common cause of constipation in toddlers and school-aged children.
It’s thought to have several causes, which include suboptimal hydration; dietary factors, like low fiber or high dairy intake; a low activity level; and behavioral factors, such as school entry and toilet training.
And here’s one last clinical pearl! Children with chronic constipation occasionally develop encopresis with overflow incontinence.
This condition begins when a child associates stooling with pain or fear, and subsequently avoids defecation and withholds stool.
As a result, the rectum becomes so distended that the child eventually loses the urge to defecate. Fecal matter accumulates and becomes impacted in the rectum, which ultimately leads to involuntary leakage of liquid stool around a large fecal mass.
These children appear to have diarrhea, when in reality they have constipation with overflow fecal incontinence! Alright, as a quick recap… Once you’ve diagnosed constipation, your next step is to assess your patient’s age to differentiate the underlying cause.

Review10:20–11:06

Newborns who fail to pass meconium within 48 hours of birth might have an anorectal malformation, meconium ileus, or Hirschprung disease; while those who pass meconium within 48 hours of birth might have a spinal cord abnormality.
For infants or older children, constipation may represent a medication or toxin effect, or an organic cause such as hypothyroidism or celiac disease.
Finally, if no underlying pathology is uncovered, consider functional gastrointestinal disorders like IBS-C and functional constipation.