Potential Efficacy of Ondansetron for Irritable Bowel -More Studies Needed

A recent correspondence letter (CJ Black, AC Ford. AJG 2020; doi: 10.14309/ajg.0000000000000932. Full text: Efficacy of Ondansetron for Irritable Bowel Syndrome With Diarrhea) shows that ondansetron could be an effective option for irritable bowel syndrome with diarrhea. Thanks to Ben Gold for this reference.

Ethical Dilemmas and Digestive Symptoms –Common with COVID-19

Ethical Dilemmas:

Full link: NEJM: Facing Covid-19 in Italy — Ethics, Logistics, and Therapeutics on the Epidemic’s Front Line

That truth is rather grim. Though Italy’s health system is highly regarded and has 3.2 hospital beds per 1000 people (as compared with 2.8 in the United States), it has been impossible to meet the needs of so many critically ill patients simultaneously…

If protecting patients is difficult, so is protecting health care workers, including nurses, respiratory therapists, and those tasked to clean the rooms between patients…

Though approaches vary even within a single hospital, I sensed that age was often given the most weight.

In the midst of the outbreak’s peak in northern Italy, as physicians struggled to wean patients off ventilators while others developed severe respiratory decompensation, hospitals had to lower the age cutoff — from 80 to 75 at one hospital, for instance…

The first and most important is to separate clinicians providing care from those making triage decisions. The “triage officer,” backed by a team with expertise in nursing and respiratory therapy, would make resource-allocation decisions and communicate them to the clinical team, the patient, and the family.

Digestive Symptoms:

From ACG: Full Link: ACG Media Statement

Excerpt:  (March 18, 2020) – Digestive symptoms are common in COVID19, occurring as the chief complaint in nearly half of patients presenting to hospital according to a new
descriptive, cross-sectional multicenter study from China by investigators from the Wuhan Medical Treatment Expert Group for COVID-19 published today in The American Journal of Gastroenterology

Key findings:

  • Compared to COVID-19 patients without digestive symptoms, those with digestive symptoms have a longer time from onset to admission and a worse clinical outcome according to this analysis by investigators from several hospitals and research centers in China who gathered data on 204 patients with COVID-19 presenting to three
    hospitals in Hubei province from January 18, 2020 to February 28, 2020.
  • Patients with digestive symptoms had a variety of manifestations, such as anorexia (83 [83.8%] cases), diarrhea (29 [29.3%] cases), vomiting (8 [0.8%] cases), and abdominal pain (4 [0.4%] cases)
  • As the severity of the disease increased, digestive symptoms became more pronounced.
  • Link to study: Pan L, et al., Clinical characteristics of COVID-19 patients with digestive symptoms in Hubei, China: a descriptive, cross-sectional, multicenter study, Am J Gastroenterol 


My Favorite Posts from the Past Year

Recently, I listed the posts that had the most views in the past year –some dating back to 2012.  The following list includes less viewed but some of my favorite posts from 2018:





Flowers in Calgary

Lessons in Diarrhea (part 1)

One of the most influential medical articles that I’ve read this year: JR Thiagarajah et al. Gastroenterology 2018; 154: 2045-59. (Senior authors/corresponding authors: Yaron Avitzur and Martin Martin).  This article provides an excellent review of the terminology and provides algorithms to help in the evaluation of chronic diarrhea in infants.  These algorithms incorporate the role of exome sequencing.

The first part of this review focuses on terminology:

  • For those with persistent and severe diarrhea that is not due to an acquired short bowel syndrome (eg. from necrotizing enterocolitis, gastroschisis, or volvulus), the authors use the term congenital diarrhea and enteropathies (CODEs).  They suggest using CODEs in place of intractable or protracted diarrhea of infancy.
  • Instead of osmotic diarrhea, the authors prefer diet-induced diarrhea since all diarrhea involves osmotic forces.  Typically, with this type of diarrhea, stool osmotic gap is >100 mOsm.
  • Secretory diarrhea “is also imprecise…We prefer to use the term electrolyte-transport-related diarrhea” (eg. congenital sodium or congenital chloride diarrhea)

Key points:

  • Most acquired diarrhea is related to infectious agents and to allergic disorders. Though, persistent diarrhea after an infection could be an early sign of a primary immunodeficiency.
  • Stool osmotic gap: = 290 – 2 x (Stool Na + Stool K).  Osmotic gap >100 mOsm is high, <50 mOsm is low.
  • Stool osmolality in almost all cases is isomolar to serum (~290).  If there is suspicion of improper collection or tampering, then this can provide objective evidence of this.
  • Reducing substances >0.5% indicates malabsorption of monosaccharides. Low pH (<5.3) is indicative of carbohydrate malabsorption (due to abundance of short-chain fatty acids that are products of fermentation)
  • Elastase is “unchanged by intestinal proteases and if low can imply pancreatic insufficiency.”  Falsely-low values can occur due to dilution in high-volume diarrhea.
  • Alpha-one-antitrypsin is largely resistant to intestinal proteases and elevation indicates excess enteric protein loss (eg. protein-losing enteropathy)

Diagnostic evaluation:

  • See figure 1 in review.  Initial evaluation after exclusion of acquired diarrheas (eg infection/allergic): History, Blood tests (CBC, CMP, CRP, ESR, IgG, lipid panel), Stool tests (electrolytes, reducing substances, elastase, fecal fat, A1AT, pH, calprotectin/lactoferrin).
  • Determining stool output may require a “urine catheter for a few days” for accuracy and help elucidate the effect of fasting on stool output.
  • Figure 2 divides evaluation based on type of diarrhea: watery, fatty, and bloody.
  • Fatty diarrhea may be due to pancreatic insufficiency, abetalipoproteinemia and chylomicron retention disease.  The latter two disorders typically are indicated by fat-laden enterocytes in histologic sections
  • Bloody diarrhea “should precipitate investigation for very-early-onset inflammatory bowel disease, autoimmune enteropathy, or primary immunodeficiency”
  • Watery diarrhea –see tomorrow’s post.  Before undergoing extensive evaluation, the authors recommend obtaining an UGI/SBFT to exclude congenital short bowel syndrome.

My take: after initial exclusion of common causes for diarrhea in infancy, early endoscopy is needed along with early use of genetic testing.

Related blog posts:

Disclaimer: These blog posts are for educational purposes only. Specific dosing of medications (along with potential adverse effects) should be confirmed by prescribing physician.  This content is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a condition.

Little Talbot State Park


World Congress 2016 Postgraduate Course

I’ve attached (with permission) the syllabus from the World Congress 2016 Postgraduate Course: 2016-world-congress-postgraduate-course-syllabus



One lecture that I will highlight with a few slides is from Dr. Martin Martin (pg 53-62) which emphasizes a new model for evaluating neonatal intestinal failure/congenital diarrhea by using whole exome sequencing –see slides below.

Other pointers:

  • Pg 82.  Breastmilk associated with shorter duration of TPN dependence in short bowel syndrome
  • Pg 137. Look for vasculopathy (MRI/MRA) and renal disease in Alagille syndrome
  • Pg 152. Lactated ringer’s likely better in acute pancreatitis than normal saline.
  • Pg 171. If constipation at less than 1 year is untreated, >60% have issues with constipation at age 3.

screen-shot-2016-10-14-at-11-37-07-am screen-shot-2016-10-14-at-11-37-00-am screen-shot-2016-10-14-at-11-36-44-am screen-shot-2016-10-14-at-11-36-34-am screen-shot-2016-10-14-at-11-35-40-am


Disclaimer: These blog posts are for educational purposes only. Specific dosing of medications/diets (along with potential adverse effects) should be confirmed by prescribing physician/nutritionist.  This content is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a condition.

Rough Skin -Tough Case

Briefly noted:

“D is Delay” NEJM 2014; 371: 2218-23.  This case presentation described how a 47-year-old homeless man presented with a neuropathy and over the course of FIVE YEARS developed dermatitis, diarrhea, and dementia.  Ultimately, he was diagnosed with niacin deficiency or pellagra. It is almost painful reading the case report knowing how long it took to establish the diagnosis. Take home points from this case report:

  • Pellagra is derived from the Italian pelle agra which means “rough skin”
  • Nutritional deficiencies are difficult to diagnose in this country due to their rarity/lack of pattern recognition

How Proton Pump Inhibitors Can Cause Infections

In yesterday’s blog, the editorial on “Acid-reducing agents in infants and children: friend or foe?” also commented on an additional study (JAMA Pediatr. 2014. doi: 10.1001/jamapediatrics.2014.696) which addresses the issue of how proton pump inhibitors (PPIs) may contribute to an increased risk of infections.  It is well-known that use of PPIs (and to a lesser extent histamine-2 receptor antagonists) contribute to a significant increased risk of community-acquired pneumonias and gastrointestinal infections (probably including necrotizing enterocolitis in infants).

In this study, (from the editorial) “acid suppression was associated with a positive gastric culture (P =.003) and increased median concentration of gastric bacteria (P<.001). Full-column nonacid reflux was associated with higher concentrations of bacteria in the lung.”

In this era of pioneering microbiome research, it is not surprising that chronic changes in gastric acid production could cause these results.  This is something to consider when calculating risks and benefits, particularly in situations where the benefits are quite minimal.

Here’s the abstract:

Importance  The use of acid suppression has been associated with an increased risk of upper and lower respiratory tract infections in the outpatient setting but the mechanism behind this increased risk is unknown. We hypothesize that this infection risk results from gastric bacterial overgrowth with subsequent seeding of the lungs.

Objectives  To determine if acid-suppression use results in gastric bacterial overgrowth, if there are changes in lung microflora associated with the use of acid suppression, and if changes in lung microflora are related to full-column nonacid gastroesophageal reflux.

Design, Setting, and Participants  A 5-year prospective cohort study at a tertiary care center where children ages 1 to 18 years were undergoing bronchoscopy and endoscopy for the evaluation of chronic cough. Acid-suppression use was assessed through questionnaires with confirmation using an electronic medical record review.

Main Outcomes and Measures  Our primary outcome was to compare differences in concentration and prevalence of gastric and lung bacteria between patients who were and were not receiving acid-suppression therapy. We compared medians using the Wilcoxon signed rank test and determined prevalence ratios using asymptotic standard errors and 95% confidence intervals. We determined correlations between continuous variables using Pearson correlation coefficients and compared categorical variables using the Fisher exact test.

Results  Forty-six percent of patients taking acid-suppression medication had gastric bacterial growth compared with 18% of untreated patients (P = .003). Staphylococcus (prevalence ratio, 12.75 [95% CI, 1.72-94.36]), Streptococcus (prevalence ratio, 6.91 [95% CI, 1.64-29.02]), Veillonella (prevalence ratio, 9.56 [95% CI, 1.26-72.67]), Dermabacter (prevalence ratio, 4.78 [95% CI, 1.09-21.02]), and Rothia (prevalence ratio, 6.38 [95% CI, 1.50-27.02]) were found more commonly in the gastric fluid of treated patients. The median bacterial concentration was higher in treated patients than in untreated patients (P = .001). There was no difference in the prevalence (P > .23) of different bacterial genera or the median concentration of total bacteria (P = .85) in the lungs between treated and untreated patients. There were significant positive correlations between proximal nonacid reflux burden and lung concentrations of Bacillus (r = 0.47, P = .005), Dermabacter (r = 0.37, P = .008), Lactobacillus (r = 0.45, P = .001), Peptostreptococcus (r = 0.37,P = .008), and Capnocytophagia (r = 0.37, P = .008).

Conclusions and Relevance  Acid-suppression use results in gastric bacterial overgrowth of genera including Staphylococcus and Streptococcus. Full-column nonacid reflux is associated with greater concentrations of bacteria in the lung. Additional studies are needed to determine if acid suppression–related microflora changes predict clinical infection risk; these results suggest that acid suppression use may need to be limited in patients at risk for infections.

Related blog posts:

Clostridium difficile Epidemiology

A recent study shows that Clostridium difficile infection (CDI) is identified frequently in young children and that approximately three-fourths had recent preceding antibiotics (Pediatrics 2014; 133: 651-58). Abstract link.

Methods: “Data from an active population- and laboratory-based CDI surveillance in 10 US geographic areas during 2010–2011 were used to identify cases.”

Key findings:

  • Of 944 pediatric CDI cases identified, 71% were community-acquired
  • CDI incidence per 100 000 children was highest among 1-year-olds (66.3)
  • Using a representative sample (n=84) who reported diarrhea on the day of stool collection, 73% received antibiotics during the previous 12 weeks.

Despite the frequency of CDI, understanding a couple of key diagnostic pearls is crucial. According to the American Academy of Pediatrics Committee on Infectious Disease policy guideline: (Link to AAP guideline PDF)

  • Recommends avoid routine testing in pediatric patients less than 1 year of age due to high carriage rates.
  • “Testing for C difficile can be considered in children 1 to 3 years of age with diarrhea, but testing for other causes of diarrhea, particularly viral, is recommended first>
  • “A common mistake is to… test for cure. C difficile, its toxins, and genome are shed for long periods after resolution of diarrheal symptoms.”
  • “An interval greater than 4 weeks since last testing should be used for testing with a recurrence.”

Bottomline: This most recent study reinforces the notion that about 1/4th of pediatric CDI occurs in the absence of recent antibiotics; nevertheless, understanding the limitations of testing for CDI could prevent a fair amount of aggravation.

Related blog posts:

Diarrhea -a Universal Experience

To be clear, by the term “universal” I am in no way referring to a theme park.  A recent review in the NEJM (N Engl J Med 2014; 370:1532-1540discusses acute diarrhea, http://nej.md/1l2bAIn .

“In the United States, there are approximately 179 million cases of acute diarrhea per year. This update on the diagnosis and management of acute diarrhea in immunocompetent adults gives particular attention to the roles of noroviruses and Clostridium difficile.”

This post is mainly to provide an up-to-date useful reference.

Microscopic, Lymphocytic and Collagenous Colitis

Microscopic Colitis (MC) is a rare pediatric problems and occurs when chronic diarrhea occurs in the presence of a normal-appearing endoscopic exam but with abnormal histology.  In adult populations, microscopic colitis is seen more frequently and can be confused with irritable bowel syndrome.  The two subtypes:

  • Lymphocytic Colitis (LC):  >20 intraepithelial lymphocytes/100 colonocytes
  • Collagenous Colitis (CC): thickened subeptihelial collagen band in addition to changes seen with LC

In a recent study (JPGN 2013; 57: 557-61), 27 MC cases were identified from a pathology database between 1995-2011.  5 were excluded due to an enteric infection.  Among the 22 other cases, 19 had LC and 3 had CC.  Association with celiac disease was evident in 4 patients and many had preceding drug exposures.

Treatment included steroids, melamine, an bismuth.

Additional references:

  • -JPGN 2011; 53: 579. lymphocytic colitis case report
  • -Clincal Gastro & Hep 2011; 9: 13.  Celaic with persistent symptoms: consider poor adherence**, SBBO*, pancreatic insufficiency*, refractory celiac (rare), PLE, giardia, malignancy, lactose intolerance, functional d/o*, microscopic colitis, Crohn’s*, NSAIDs
  • -Gut 2009; 58: 68-72. Collagenous colitis: Budesonide at 6mg/day maintained remission in ~25%.
  • Gastro 2008; 135: 1510.  Budesonide effective for collagenous colitis; n=48, 9mg/day.
  • -Gastro 2011; 140: 1155. Review of microscopic colitis/collagenous colitis.
  • -Am J Gastroenterol 2010; 105: 859-865.  n=466 & 451 controls.  Microscopic colitis present in 1.5% of IBS patients.  IBS pts with lower incidence of adenomas (7.7.% vs 26%).  9% had diverticulosis (lower).
  • -Clin Gastro & hep 2009; 7: 1210. 4.3% of pts w microscopic colitis had celiac. 44/1009.