What to Make of A Motility Study of Children with Orthostatic Intolerance

While a recent study (A Darbari et al JPGN 2016; 63: 329-35) provides some interesting data regarding the potential origin of gastrointestinal symptoms in the setting of orthostatic intolerance, I cannot support their conclusion that antroduodenal manometry (ADM) “should” be part of the evaluation of these affected children.

Background:

  • Retrospective study which included only subjects with a positive tilt test

What’s interesting:

  • Among 35 children with orthostatic intolerance due to either neurally mediated hypotension (NMH) or postural orthostatic tachycardia syndrome (POTS), ADM was abnormal at baseline or during tilt table testing in 26 (75%).
  • ADM studies were more often abnormal than gastric emptying studies, which were normal in 12 or 25.
  • Specific findings included neurogenic intestinal dysmotility in 15, antral hypomotility in 4, visceral hyperalgesia in 2, and regurgitation in 5.
  • GI symptoms of nausea, abdominal pain or vomiting were reproduced during tilt testing in 31 of 35 patients (89%).

Based on the discussion, the authors imply that ADM testing could help determine if the symptoms are due to neurogastrointestinal pathology or if normal, could indicate a central origin for the GI symptoms.  Thus, they conclude that motility testing “should” be part of comprehensive” orthostatic intolerance evaluation.

I would argue that this study does not show that ADM testing can reliably distinguish whether symptoms are due to a neurogastroenterological pathology or central pathology. And, in fact, there are better tests to examine for central origin.  I wouldn’t be surprised if many of their subjects had brain imaging, though this is not reported.

In addition, the authors acknowledge that ADM testing may not influence therapeutic decisions.  “The clinical response to promotility agents in children with POTS is generally low.”

My take: This study provides a useful mechanistic explanation of symptoms associated with orthostatic intolerance.  However, “I’m not there yet” on supporting ADM for all children with OI.

Related blog post:

Avalanche Creek Lake, Glacier Natl Park

Avalanche Creek Lake, Glacier Natl Park

 

Fundoplication effects on esophageal motility

Trying to decide whether a child should undergo a fundoplication is often quite difficult.  The best candidates with gastroesophageal reflux disease (GERD) don’t need surgery because medical treatment is usually effective.  Typical patients who fail medical treatments may have numerous comorbidities that could cause a complicated postoperative course or failure of the procedure.

One aspect about the surgery that has been questioned has been whether surgery causes dysmotility of the esophagus.  A recent article describes a study, which enrolled only ten children who had surgery; however, these patients underwent extensive preoperative and postoperative evaluations to try to provide more information about the motility effects of fundoplication (J Pediatr 2013; 162: 566-73).

Patients were considered for surgery if they had failed medical therapy. Four of the ten patients were neurologically-impaired. Testing included automated impedance manometry, 24-hour pH-impedance, gastric emptying breath test, and GERD questionnaires (though the authors note that GERD questionnaires are not validated in children aged 1-12 years).  Median patient age was 6.4 years, with a range of 1-17 years.

Surgery: laparascopic anterior partial fundoplication

Results:

  • 4 patients developed postoperative dysphagia, two patients had redo fundoplications (one due to dysphagia and one due to persistent emesis).
  • Postsurgery, GER measures were reduced.  Total number of acid reflux episodes dropped from an average of 37 to an average of 10.  Total GER (acid and nonacid) episodes dropped from an average of 97 to an average of 66.  The percentage of time with pH<4 dropped as well from an average of 12.5% to an average of 3.1%.
  • Average gastric emptying time was unchanged: 64 minutes pre surgery and 63 minutes post surgery.
  • Conventional esophageal motility measures/peristaltic contractions were unaltered.  However, patients with postoperative dysphagia had longer gastric emptying times compared with those who did not develop postoperative dysphagia.

Related blog posts:

The Medical Pendulum and Gastroesophageal Reflux | gutsandgrowth

Gastroesophageal Reflux: I know it when I see it | gutsandgrowth

Related references:

  • -Gastroenterology 2011; 141: 1938 LOTUS study in JAMA summarized. JAMA 2011; 305: 1969. Medical rx outperformed surgery. 92% under control (remission) with long-term medical Rx vs 85% with surgery & fewer side effects of medical Rx.
  • -Clin Gastro & Hepatology 2009; 7: 1292, 1264 (editorial). 12 yr outcomes for surgery vs PPI. n=154 omeprazole, n=144 surgery. Similar long-term outcome ~50% with long-term remission.
  • -JPGN 2010; 50: 25. Reflux detected by impedance does NOT determine fundoplication outcome. n=34.
  • -JPGN 2006; 43: 185.  Effect of fundo: no change in  gastric motor activity & increased discomfort with distention
  • -Pediatrics 2006; 118: 2326. n=1142. Fundoplication decreased hospitalization rates for children <4yrs; in older children with developmental delay, there were increased hospitalization rates after fundoplication. (47% had no hospitalizations prior to fundoplication.)
  • -Clin Gastro & Hep 2004; 2: 978-984. Gilger et al. n=198. 63% required p-op medical treatment for recurrent GERD -retrospective review 1996-99.
  • -J Pediatrics 2011; 159: 597. Hypoglycemia (likely due to dumping) was common post-op. n=285. 24% of screened children with low glucose (only 1.3%of those without formal screening). 2/3rds with hypoglycemia had preceding hyperglycemia. Only 53% had dumping symptoms.  Many in this cohort were NICU pts -~1/3rd of pts had mean age of 3months & another ~1/3rd with mean age of 6months.Rx often was continuous feeds.
  • -Pediatrics 2006; 118:1828. 48,665 antireflux surgeries done from 1996-2003 (~7000/yr) in US
  • -Clin Gastro & Hep 2006; 4: 299. Frequent complications p-op and frequent need for GERD meds. dysphagia in 19%, dilation in 6%, repeat surgery in 2%, mortality in 0.8% (n=3145). 50% required GERD meds.
  • -Gastroenterology 2001; 121: 5-14 & 214.  Dysmotility with GER reflects severe disease & is present ~30%. According to this study, dysmotility does not affect postoperative outcome, is not corrected by fundoplication, may occur p-op, and requires no tailoring of surgical mgt.

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