#66: Constipation (Let It Flow!) – We’ve Been Waiting So Long For This Episode To Come Out!

October 12, 2022 | By Sam Masur

Summary

Join us as Dr. Lu puts the “Func” in Functional Constipation. Dr. Peter Lu, pediatric gastroenterologist and motility specialist at Nationwide Children’s Hospital teaches us what is required for diagnosing constipation, tips for management, diagnostic and therapeutic snags to avoid, and the true impact of this common diagnosis. So sit back, re(mira)lax, and enjoy the show!

Credits

• Producer, Writer, & Infographic:  Brian Ward MD
• Executive Producer: Max Cruz MD
• Showrunner: Sam Masur MD
• Cover Art: Chris Chiu MD
• Hosts: Justin Berk MD, Chris Chiu MD
• Editor:Justin Berk MD; Clair Morgan of nodderly.com
• Guest: Peter Lu MD

Constipation Pearls

1. A well-gathered history and physical exam may be enough to adequately rule out organic causes, obtain a working diagnosis of functional constipation, and begin treatment.
2. Common first-line tests to rule out organic causes of constipation include thyroid function tests, celiac panel, and basic chemistries.
3. Some osmotic laxatives like PEG-3350 can be safely  titrated by families at home, with some guidance.
4. Stimulant Laxatives like senna and bisacodyl are safe and effective in children. Senna can be crushed.
5. Enemas (mineral oil or bisacodyl) can greatly aid cleanouts when the patient has a large rectal stool ball.
6. Intractable constipation after adequate first-line therapies, concern for organic causes, or a story that just doesn’t fit are all appropriate referrals to pediatric gastroenterology.

SPONSORS: VCU Health CE

We are excited to announce that the Cribsiders are now partnering with VCU Health Continuing Education to offer continuing education credits for physicians and other healthcare professionals. Check out cribsiders.vcuhealth.org and create your FREE account!

Constipation Notes 

Defining Functional Constipation:

Functional constipation is defined as decreased bowel movements/changes in bowel patterns and the absence of “organic causes” aka other disease processes. First, let’s tackle bowl patterns using the Rome IV criteria.

What is Constipation, feat: the ROME IV Criteria:

NASPGHAN defines functional constipation with the Rome IV criteria. There is one set of criteria for infants and children 0-4 years of age and a second set for ages 4-17 years. Taken directly from the guideline paper, the criteria are two or more of the following:

For children less than 4 years old:

1.    < 2 defecations per week.
2.     At least 1 episode of incontinence per week after the acquisition of toileting skills.
   • Dr. Lu tip: this one impacts quality of life the most. Take encopresis seriously!
3.     History of excessive stool retention.
4.     History of painful or hard bowel movements.
5.     Presence of a large fecal mass in the rectum.
   • May be seen on X-ray or noted with digital rectal exam (DRE). Note, X-ray can be used to visualize a large stool burden, but the “normal” amount of poop is highly variable and there is low inter-rater reliability of stool burden on KUB. Lastly, while an X-ray can be helpful, it doesn’t make the diagnosis—you do! Check out this great “things we do for no reason” paper for more info.
6.     History of large-diameter stools that may obstruct the toilet.

For children greater than 4 years old*:

1.     < 2 defecations in the toilet per week.
2.     At least 1 episode of fecal incontinence per week.
3.     History of retentive posturing or excessive volitional stool retention.
   • Be careful to not confuse dichasia (difficulty coordinating) with straining or painful movements.
4.     History of painful or hard bowel movements.
5.     Presence of a large fecal mass in the rectum.
6.     History of large-diameter stools that may obstruct the toilet. 

*The NASPGHAN paper states developmental age of 4 years old, which can come down to clinical judgement.

Bristol stool chart: Great for research and can be helpful in clinic, however Dr. Lu and others use lots of descriptors or describes consistency in relation to food instead, as kids and parents alike may find this easier to understand (hot cocoa, mashed potatoes, banana, raisins/pebbles).

Red Flags and Other Diseases to Look Out For:

Below you will find a (nearly) exhaustive list of diseases that could mimic functional constipation. A well-gathered history and physical exam may be enough to adequately rule out organic causes, obtain a working diagnosis of functional constipation, and begin treatment. Put another way, testing can be reserved for strange stories or when conservative management fails.

Some of the more common tests obtained are: 

• Celiac tests (anti-TTG IgA and total IgA level)
• Thyroid function (TSH and T4)
• Basic chemistries (CMP)

The “Organic” Causes of Constipation (in no particular order)

• Celiac disease (family history, labs)
• Hypothyroidism, hypercalcemia, hypokalemia (family history, labs)
• Cystic fibrosis (frequently on the newborn screen. Note that GI manifestations like failure to thrive and constipation generally occur earlier in life than pulmonary manifestations)
• Hirschsprung’s Disease (early history of constipation, though delayed presentation is possible as the segmental length is variable)
• Diabetes mellitus (history, labs)
• Dietary protein allergy
• Drugs and toxics 
  • Opiates
  • Anticholinergics
  • Antidepressants
  • Chemotherapy
  • Heavy metal ingestion (lead) 
  • Vitamin D intoxication
  • Botulism
• Anal achalasia
• Anatomic malformations (physical exam)
  • Imperforate anus
  • Anal stenosis
• Pelvic mass (sacral teratoma)
• Spinal cord anomalies, trauma, tethered cord
• Abnormal abdominal musculature (prune belly, gastroschisis, Down syndrome)
• Pseudoobstruction (visceral neuropathies, myopathies)
• Multiple endocrine neoplasia type 2 

Risk Factors for Developing Functional Constipation:

Higher Risk times for Developing Constipation:

• Introduction of solid food 
  • Food protein proctitis (aka cow’s milk allergy) can lead to withholding due to pain with defecation at an early age.
  • Incorrect mixing of formula can lead to constipation, but there is no evidence that correctly mixed formula increases risk of constipation. 
•  Toilet training
•  Starting school
• Large and stressful life changes

Exercise:

• Insufficient evidence to judge if physical activity/sedentary lifestyle increases the risk for constipation, though anecdotally normal healthy physical activity may be correlated with more regular stooling patterns.

Diet:

Diet should be well-rounded, including fruits and veggies.

•  Fiber: according to Dr. Lu, there is not good data that increasing fiber intake (beyond the usual/above what is normally recommended) improves constipation. Encourage ADEQUATE fiber.
  •  Prunes, apples, pears, and kiwis are all great sources of fiber, however studies show that our standard laxatives are more effective in treating constipation.
•  Milk: there is insufficient evidence to suggest that milk leads to constipation
•  Fluids: while dehydration can lead to harder stools, increasing hydration above the normal recommended amount “just makes kids pee more” and will not cure constipation. Encourage ADEQUATE hydration.

A Word on Disparities:

While we do not have much evidence on constipation prevalence by race, we do know that these disparities exist again and again in medicine. Food deserts, increased prevalence of ACE’s, and decreased access to medical care all have the potential to exacerbate functional constipation for our patients in minority communities. Be on the lookout for these issues!

Neurodivergence, especially ASD is correlated with functional constipation.

Treatment of Constipation (Let it Flow!) 

If functional constipation is suspected or diagnosed, start with an osmotic laxative. In toddlers and school aged children, stimulant laxatives can be used. Below you will find specific tips for age groups.

Osmotic Laxatives:

Osmotics draw fluid into the stool content thereby softening stool. All osmotics have similar efficacy, however PEG-3350 is generally the best tolerated. 3350 refers to the average molecular weight.

• PEG-3350 (MiraLax)
• Lactulose
• Milk of magnesia
• Mineral oil

Stimulant Laxatives:

• Senna
• Bisacodyl

Honorable Mentions:

• Docusate has not been shown to be effective.

Treatment Tips by age:

Infants Prior to Solid Food Introduction:

Verify formula mixing, then consider eliminating milk protein, soy. Consider a diagnosis of Hirschsprung’s at this time as well. 

Infants Who Have Introduced foods: 

Consider stool softeners like lactulose, milk of magnesia, or PEG-3350.

Toddlers and School Aged Children:

If osmotic laxatives are not working, stimulants can be added for adjunctive therapy. Senna and bisacodyl have similar effects, but senna can be crushed and is therefore more readily tolerated. According to Dr. Lu, there is very little evidence of “making the colon lazy” or dependent on laxatives. Withholding and chronic distension of the colon is much more likely to make the colon less effective. 

Nonpharmacologic techniques and behavioral therapies help significantly, like tracking stools, using reward systems, or partnering with psychologists or behavior therapists.

Cleanouts:

Cleanouts may be needed for children with fecal incontinence/encopresis or a large stool ball in the rectum. Cleanouts consist of higher doses of PEG-3350 and a stimulant laxative before and after. Mineral oil or bisacodyl enemas can be used as well for known rectal stool-balls.

Some children require admission to hospital for intractable constipation, prior failed at-home cleanouts, or manual disimpaction in the OR.

Specialized Therapies (for the curious, but probably not prescribed in the Primary Care setting):

A number of medications used in the adult world are making their way to pediatrics. Including secretagogues like linaclotide and libuprostone, as well as promotility agents like prucalopride. All of these three have had positive cohort studies, but RCTs in children that were negative. Dr. Lu’s expert opinion is that constipation can be varied in children and therefore targeted IBS treatments like those used in adults may seem less efficacious in children when studied in aggregate.

Biofeedback/physiotherapy can also be used for patients with previously diagnosed pelvic floor dysfunction.

When to Refer to Pediatric Gastroenterology:

The vast majority of kids with functional constipation will improve with basic treatment, behavioral strategies, osmotic laxative, and one stimulant. Intractable constipation after adequate first line therapies, concern for organic causes, or a story that just doesn’t fit are all appropriate referrals.  

Pediatric gut motility specialists can perform specialized testing like anorectal manometry or full thickness biopsies (diagnostic for Hirschsprung’s), and more!

Links:

• Pediatric GI podcast Bowel Sounds
• NASPGHAN toolbox  for guidelines etc.

Goal

Listeners will explain the basic diagnosis and management of pediatric functional constipation.

Learning Objectives

After listening to this episode listeners will be able to…  

1. Explainthe impact of constipation on the pediatric population.
2. List common organic causes of constipation and how to rule them out.
3. Identify risk factors for development of constipation including lifestyle factors and neurodivergence.
4. Describe a basic approach to constipation treatment including when to use stimulant laxatives, cleanouts, and when to refer to pediatric gastroenterology.

Disclosures

Dr. Lu reports no relevant financial disclosures. The Cribsiders report no relevant financial disclosures. 

Citation

Ward B., Lu P., Cruz M, Masur S, Chiu C, Berk J. “#66: Constipation (Let It Flow!) – We’ve Been Waiting So Long For This Episode To Come Out!”. The Cribsiders Pediatric Podcast. https:/www.thecribsiders.com/ October 12, 2020.