Clues about constipation and more than 2.5 million views

A recent article identifies some important factors contributing to constipation in Hong Kong children (JPGN 2012; 55: 56-61).

Using a territory-wide questionnaire in 2318, Hong Kong Chinese elementary school students, the authors identified several factors associated with constipation which was present in 12.2% of this cohort:

  • Refusal to pass bowel movements at school (OR 1.97).  In Hong Kong, students spend >8 hours per day at school.
  • Having dinner with one/both parents <50% of time (OR 1.52).  May indicate less time with parents and less parental prompting.
  • Nighttime sleep <7 hours (OR 1.87).  This is postulated to be related to increased homework and more stress which may affect gut motility.
  • Frequent fast food consumption (OR 1.14).  This may be associated with less fiber intake.

On a tangential note, one of my sons informed me of “bad lip reading” on YouTube; some of these clips are really funny.  Since there was one relevant to the subject at hand, with over 2.5 million views, I’ve provided a link:

“Everybody Poops” – a bad lip reading of the Black Eyed Peas …

Additional blog entries related to constipation:

Stimulants for constipation

Diagnostic tests hardly ever help patients poop

It’s worth the cost

Think twice about checking thyroid

Stimulants for constipation

Overall, 12-19% of Americans are affected by chronic constipation (Am J Gastroenterol 2004; 9: 750-59).  Despite the fact that constipation problems are widespread, the amount of useful research available to guide treatment is quite limited.  Two recent articles do offer some information:

  • Clin Gastroenterol Hepatol 2011; 9: 577-83.
  • Gut 2011; 60: 209-18.

The first reference examined the use of bisacodyl in a randomized, double-blind placebo-controlled study in the UK.  During the 4-week treatment period, patients receiving 10mg/day bisacodyl (n=247) had increased stools, from 1.1 per week to 5.2 per week.  Stool frequency also increased to 1.9 per week in the placebo group (n=121).  All secondary endpoints including constipation-associated symptoms (eg. quality of life indices, physical discomfort) improved significantly compared to placebo.  Average age of patients in this study was 55 years.  The main adverse effect was diarrhea –mainly during the 1st week of therapy.

A selected summary in Gastroenterology (Gastroenterology 2012; 142: 402-404) reviews the first study and makes several useful points:

  • Stimulant laxative use has been hindered by myths & misconceptions along with lack of supporting data.  Most recent studies do not support a role of stimulant use in causing enteric neuropathies, a cathartic colon or increasing the risk of colon cancer
  • Osmotic laxatives have been favored in guidelines but this has not been bolstered by supporting data
  • Only recently have two large randomized controlled studies proven the efficacy and safety of stimulant laxatives over the short-term
  • Long-term prospective studies are not available on the use of stimulant laxatives.

The second reference is a systematic review and meta-analysis of randomized controlled trials (RCTs) of pharmacologic therapy for chronic idiopathic constipation.  Twenty one eligible RCTs were identified: eight laxative studies (n=1411), seven prucalopride studies (n=2639), three lubiprostone (n=610), and three linactolide trials (n=1582).  All of these studies showed treatment was superior to placebo. These studies involved subjects who were mainly adults (>90% older than 16 years).

The results showed benefit from both stimulant and osmotic laxatives.  Overall, the osmotic and stimulant laxative studies showed higher response than the pharmacologic agents like prucalopride, lubiprostone, and linaclotide.  Nevertheless, between 50% and 85% of patients did not fulfill criteria for response to therapy.

Additional references:

  • -J Clin Gastro 2003; 36: 386-389.  Safety of stimulants for long-term use.
  • -Am J Gastro 2005; 100: 232-242.  Myths about constipation.  Stimulants have not been proven to cause a “cathartic colon”
  • -J Pediatr 2009; 154: 258.  Constipation associated w 3-fold increase in health utilization/cost.
  • -Clin Gastro  Hep 2009; 7: 20.  Review of complications assoc c constipation in adults.
  • -Pediatrics 2008; 121: e1334.  Behavioral therapy ineffective in treating childhood constipation.
  • -NEJM 2008; 358: 2332, 2344.  Use of methylnatrexone for opioid-induced constipation & trial of n=620 of prucalopride for severe constipation.  Both drugs were helpful.
  • -Gastroenterology 2004; 126: S33. Review of pediatric incontinence.
  • -J Pediatr 2004; 145: 253-4.  Prevalence of encopresis 15% /constipation 23% in obese children  (n=80).  Questionnaire administered to 80 consecutive obese children.
  • -Gastroenterology 2003; 125: 357.  Longterm constipation followup.  one-third with persistent constipation; 60% better at 1 year.  (tertiary referral group)
  • -Pediatrics 2004; 113: 1753 & e520.  When constipation & toileting difficulties both occur, constipation usually precedes toileting problems

Think twice about checking thyroid

Hypothyroidism is not a frequent cause of constipation in children (JPGN 2012; 54: 285-87).  According to this study, the yield on checking for hypothyroidism in pediatric patients with constipation is no greater than in the general population.

This retrospective study examined the records of 873 patients who underwent thyroid testing ordered by pediatric gastroenterology; 443 (51%) had isolated constipation.  In all, 56 had abnormal thyroid function testing though 40 were normal on repeat testing. Of these 16 remaining cases, 7 were known to have hypothyroidism.  Of the nine remaining “new” cases, 3 had slow growth (2 without constipation), 3 had trisomy 21, and 2 were taking medications which affect thyroid function.  This leaves only 1 patient who presented with constipation without a clear risk factor or other indication for testing.

The authors state that 1/443 (0.2%) is quite similar to background incidence of hypothyroidism (0.3%).  The costs of identifying this case would exceed $18,000 but could be considered much higher (~$200,000) when all of the costs of false-positives are considered (eg. endocrinology consultations, followup testing).  In patients with slow growth (with or without constipation), about 2.5% had hypothyroidism.

In short, think twice about checking thyroid status in patients with isolated constipation.

Additional references:

  • -JPGN 2011; 53: S2. 49, 55. ‘Rarely do children with constipation need w/u’–only if alarming features: Delayed meconium, bilious vomiting, bloody stools, fever, bladder disorders, poor growth, NO RESPONSE to conventional treatment, abnormal exam. 25% of functional constipation problems may persist into adulthood.
  • -JPGN 2010; 51: 155. Lack of utility of AXR -suggested only in uncooperative pts, concerns about abuse/concerns about psychologic impact of exam
  • -J Pediatr 2010; 156: 461-5. MRI in children with chronic constipation or not-retentive soiling (n=130, n=28) -MRI showed lumbar sacral abnormalities in 3% –none required neurosurgery (1 w spina bifida occulta, 3 w terminal filum lipomas). Prospective study.
  • JPGN 2006; 43: e1Ye13.  http://www.naspghan.org/user-assets/Documents/pdf/PositionPapers/constipation.guideline.2006.pdf  Guidelines suggest checking thyroid, calcium, celiac and lead if not responding to therapy.

It’s worth the cost

Recently the cost of Sitzmarks® increased to $175 (for 12)–it’s worth the cost.  According to one study, the use of a transit study helps determine which patients will benefit from colonic manometry (JPGN 2012; 54: 258-62).  A retrospective review of 24 children showed that all five children with normal oral-anal transit (OTT) studies had normal colonic manometry.  In contrast, 9/19 (47%) with abnormal (slow OTT) had abnormal colonic manometry.

The authors define their approach to OTT which is helpful.

  • In patients with a fecal impaction, this was cleared prior to starting study
  • If patients had difficulty with capsule ingestion, markers were administered by embedding in part of a banana or mixed with applesauce
  • Stimulant laxatives withheld for 72hrs prior to study
  • AXR obtained on days 3 and 5
  • Slow OTT (abnormal) defined as >6 markers proximal to rectum on day 5

Of those with abnormal colonic manometry, two-thirds (6) were referred for surgical intervention; one patient with normal OTT had surgery.  Surgeries:  3 cecostomy, 4 subtotal colectomy.

Additional references:

  • -JPGN 2004; 38: 75. Colostomy in 10 children with intractable constipation.
  • -Arch Dis Child. 2004 Jan;89(1):13-6. Benninga MA, Voskuijl WP, Akkerhuis GW, Taminiau JA, Buller HA. Related Articles,  Colonic transit times and behaviour profiles in children with defecation disorders.
  • -J Pediatr Surg. 2004 Jan;39(1):73-7. Youssef NN, Pensabene L, Barksdale E Jr, Di Lorenzo C.  Is there a role for surgery beyond colonic aganglionosis and anorectal malformations in children with intractable constipation?
  • -Am J Gastroenterol. 2003 May;98(5):1052-7.  Pensabene L, Youssef NN, Griffiths JM, Di Lorenzo C. Related Articles, Colonic manometry in children with defecatory disorders. role in diagnosis and management.
  • -JPGN 2002 Jul;35(1):31-8. Gutierrez C, Marco A, Nogales A, Tebar R. Total and segmental colonic transit time and anorectal manometry in children with chronic idiopathic constipation.
  • -JPGN 2001 Nov;33(5):588-91.  Villarreal J, Sood M, Zangen T, Flores A, Michel R, Reddy N, Di Lorenzo C, Hyman PE.  Colonic diversion for intractable constipation in children: colonic manometry helps guide clinical decisions.
  • -http://www.sitzmarks.com/buyonline.aspx

Diagnostic tests hardly ever help patients poop

Virtually everyday pediatric gastroenterologists like myself see children with constipation problems; managing constipation is often a Sisyphean task.  Recent articles (JPGN 2011; 53: S2: 49, 55) reiterate what all pediatric gastroenterologists already know –constipation is almost always a management problem and only rarely a diagnostic problem.  Rarely do children with constipation need diagnostic tests.  These articles recommend testing only if alarm features are present, including the following:

  • Delayed meconium passage at birth
  • Bilious vomiting
  • Bloody stools
  • Fever
  • Bladder disorders
  • Poor response to conventional treatment
  • Abnormal exam

Additionally, these articles state that about 25% of functional constipation problems may persist into adulthood.  Among the patients who respond poorly to treatment, constipation, especially if associated with soiling (aka. encopresis), can be very detrimental for obvious social reasons.  This group of patients can be very challenging.  Many of the patients do not perceive the problem to be as severe as their parents and may be unwilling to work on fixing the problem.

Clinical experience has been that younger children respond better than older children. Perhaps, this is due to a greater ease of imposing a specific treatment plan in younger children along with the fact that the physiological and behavioral changes associated with chronic constipation are not as well-established.

Other pertinent aspects of treatment and diagnosis include the following:

Abdominal xrays are not very helpful (JPGN 2010; 51: 155.) and should mainly be reserved for those in whom a rectal examination cannot adequately be performed, such as very uncooperative patients, and in patients with concerns about abuse (or concerns about psychologic impact of exam).

Also, despite earlier reports of potential sacral abnormalities in children with chronic constipation or non-retentive soiling, a fairly large prospective MRI study (J Pediatr 2010; 156: 461-5) (n=158) found that only 3% had lumbar sacral abnormalities and none required neurosurgery (1 with spina bifida occulta, 3 with terminal filum lipomas).

In addition to the scholarly references below, some useful practical sources of information can be identified by going to my office website, http://www.gicareforkids.com and clicking “constipation.”

Additional references:

  • -JPGN 2011;52: 574.  n=117.  Describes outcome with placement of a cecostomy/appendicostomy for irrigations of colon.  69% success with antegrade enemas.
  • -Gastroenterology 2009; 137: 1963. Increased rectal compliance not associated with treatment response.
  • -J Pediatr 2009; 154: 258. Constipation associated with 3-fold increase in health utilization/cost.
  • -Clin Gastro Hep 2009; 7: 20. Review of complications associated with constipation in adults.
  • -Pediatrics 2008; 121: e1334. In this study, behavioral therapy was ineffective in treating childhood constipation.
  • -JPGN 2007; 44: 5.  Review of nonretentive fecal incontinence.
  • -J Pediatr 2006; 148: 62. Higher compliance is noted in children with functional fecal retention/encopresis; thus, larger stool volume need to reach intrarectal pressure of the urge to defecate.
  • -J Pediatr 2005; 147: 700-04.  69% of infants with constipation recovered within 6 months (then 15% relapsed).
  • -Gastrointestinal Endoscopy 2004;  60(1):39–43.  A new technique for management of intractable constipation in children: percutaneous endoscopic colostomy of the left colon
  • -JPGN 2004; 38: 75.  Colostomy in 10 children with intractable constipation.
  • -J Clin Gastro 2003; 36: 386-389.  Safety of stimulants for long-term use.
  • -Am J Gastro 2005; 100: 232-242. Myths about constipation. Stimulants have not been proven to cause a “cathartic colon”
  • -JPGN 2004; 39: 448. review
  • -J Peds 2004; 145: 409. 8/88 patients with intractable constipation with spinal cord lesions (6 with tethered cords). 6/7 better p surgery. Intractable was defined as  <2BMs/week x 3 months despite laxative treatment. Only one patient had physical exam finding.  This was a retrospective study.
  • -Gastroenterology 2003; 125: 357. Long-term constipation followup.  One-third had persistent constipation; 60% better at 1 year. (tertiary referral group)
  • -Pediatrics 2004; 113: 1753 & e520. When constipation & toileting difficulties both occur, constipation usually precedes toileting problems.
  • -NEJM 2003; 349: 1360.  Review.
  • -Arch Pediatr Adolesc Med 1999; 153: 377.  Digital exam  performed in only 23% at time of referral to specialist.