Author Archives: gutsandgrowth

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About gutsandgrowth

I am a pediatric gastroenterologist at GI Care for Kids (previously called CCDHC) in Atlanta, Georgia. The goal of my blog is to share some of my reading in my field more broadly. In addition, I wanted to provide my voice to a wide range of topics that often have inaccurate or incomplete information. Before starting this blog in 2011, I would tear out articles from journals and/or keep notes in a palm pilot. This blog helps provide an updated source of information that is easy to access and search, along with links to useful multimedia sources. I was born and raised in Chattanooga. After graduating from the University of Virginia, I attended Baylor College of Medicine. I completed residency and fellowship training at the University of Cincinnati at the Children’s Hospital Medical Center. I received funding from the National Institutes of Health for molecular biology research of the gastrointestinal tract. During my fellowship, I had the opportunity to work with some of the most amazing pediatric gastroenterologists and mentors. Some of these individuals included Mitchell Cohen, William Balistreri, James Heubi, Jorge Bezerra, Colin Rudolph, John Bucuvalas, and Michael Farrell. I am grateful for their teaching and their friendship. During my training with their help, I received a nationwide award for the best research by a GI fellow. I have authored numerous publications/presentations including original research, case reports, review articles, and textbook chapters on various pediatric gastrointestinal problems. In addition, I have been recognized by Atlanta Magazine as a "Top Doctor" in my field multiple times. Currently, I am the vice chair of the section of nutrition for the Georgia Chapter of the American Academy of Pediatrics. In addition, I am an adjunct Associate Clinical Professor of Pediatrics at Emory University School of Medicine. Other society memberships have included the North American Society for Pediatric Gastroenterology Hepatology and Nutrition (NASPGHAN), American Academy of Pediatrics, the Food Allergy Network, the American Gastroenterology Association, the American Association for the Study of Liver Diseases, and the Crohn’s and Colitis Foundation. As part of a national pediatric GI organization called NASPGHAN (and its affiliated website GIKids), I have helped develop educational materials on a wide-range of gastrointestinal and liver diseases which are used across the country. Also, I have been an invited speaker for national campaigns to improve the evaluation and treatment of gastroesophageal reflux disease, celiac disease, eosinophilic esophagitis, hepatitis C, and inflammatory bowel disease (IBD). Some information on these topics has been posted at my work website, www.gicareforkids.com, which has links to multiple other useful resources. I am fortunate to work at GI Care For Kids. Our group has 17 terrific physicians with a wide range of subspecialization, including liver diseases, feeding disorders, eosinophilic diseases, inflammatory bowel disease, cystic fibrosis, DiGeorge/22q, celiac disease, and motility disorders. Many of our physicians are recognized nationally for their achievements. Our group of physicians have worked closely together for many years. None of the physicians in our group have ever left to join other groups. I have also worked with the same nurse (Bernadette) since I moved to Atlanta in 1997. For many families, more practical matters about our office include the following: – 14 office/satellite locations – physicians who speak Spanish – cutting edge research – on-site nutritionists – on-site psychology support for abdominal pain and feeding disorders – participation in ImproveCareNow to better the outcomes for children with inflammatory bowel disease – office endoscopy suite (lower costs and easier scheduling) – office infusion center (lower costs and easier for families) – easy access to nursing advice (each physician has at least one nurse) I am married and have two sons (both adults). I like to read, walk/hike, bike, swim, and play tennis with my free time. I do not have any financial relationships with pharmaceutical companies or other financial relationships to disclose. I have helped enroll patients in industry-sponsored research studies.

More intriguing than helpful

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A recent study reports that a pH-impedance (pH-MII) may help identify children with allergen-induced gastroesophageal reflux disease (GERD) after exposure to cow’s milk (J Pediatr 2012; 161: 476-81).  The study population included 17 children (average age 14 months) with a clinical diagnosis of cow’s milk allergy (CMA) who had responded to an elemental diet.

Given the limitations of the study, it is hard to take seriously the conclusions of the authors that in “selected cases of children with CMA in whom GERD is suspected” pH-MII “should be considered as part of diagnostic workup.”

The limitations:

  • CMA diagnosed clinically based on response to dietary therapy
  • GERD diagnosed based on Infant GER Questionnaire, though authors acknowledge that “we are aware that no symptom or cluster of symptoms have been shown to reliably predict the diagnosis of GERD”
  • Statistically-significant findings only for weakly acidic reflux which was induced on second day after switching from elemental formula to cow’s milk
  • No endoscopic correlation of mucosal disease or exclusion of eosinophilic esophagitis
  • Small number of patients

I cannot see how obtaining a pH-MII study would offer a meaningful benefit to these patients; though, it is intriguing that one potential measure of clinical deterioration like increased weakly acid episodes can be detected when these patients are challenged with cow’s milk.

Some related blog entries:

Impedance recommendations from PIG

Gastroesophageal Reflux: I know it when I see it

Guidelines for Eosinophilic Esophagitis

Hepatitis A vaccine immunity –will it last?

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In a previous post (HAV vaccination: how long will it take?), it was noted that U.S. HAV immunization rates are poor but much better in states that have employed a strategy of implementing universal vaccination for a longer period.  Another article provides reassurance that once patients are vaccinated that the immunity is quite durable (Hepatology 2012; 56: 516-22).

197 infants and children were followed after HAV immunization; these patients were divided into three groups; two dose immunization at 6 & 12 months (group 1), at 12 & 18 months (group 2), and at 15 & 21 months(group 3).  Anti-HAV serology was followed sequentially. At 10 years, almost all children retained seroprotection (>10 mIU/mL) levels, >95% of group 2 & 3.  In group 1,  7% of infants born to anti-HAV negative mothers and 11% of infants born to anti-HAV positive mothers did not have protective antibody levels.

Conclusion: Seropositivity for HAV persists for at least 10 years after vaccination with two-dose regimen when administered to children 12 months of age and older.

Something to think about (unrelated to blog post):

A Zen master was once asked, “What is the key to happiness?”

He answered, “Good judgment.”

“How do I gain good judgment?” he was questioned.

“Experience,” was the reply.

“How then do I get experience?” the student further probed.

“Bad judgment,” were his final words.

(quoted previously in Pediatrics and from the following link QUOTATIONS AND PASSAGES ON EXPERIENCE)

Better growth charts for preterm children

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A community-based cohort study from the Netherlands involving 1690 preterm infants (25-36 weeks) and a random sample of 634 full term infants provides a more precise tool for monitoring growth over the first four years of life (J Pediatr 2012; 161: 460-5).

Key findings:

  • The lower the gestational age, the lower the median value for both weight and height.  A quick glance at their tables indicate that infants born at 25 weeks gestation remained on average about 2 kg and 4 cm smaller than full term infants.  Infants born at 32 weeks gestation were on average about 1 kg and 2 cm smaller through the study period.
  • The absolute differences in weight and height were nearly constant, indicating that there was a lack of ‘catch-up’ growth.  At the same time, a child ‘following his own curve’ parallel to growth curve is likely a normal pattern
  • Head circumference at the end of the first year was similar between preterm and term infants
  • Greater variability was noted in boys

While this study did not adjust for maternal height, it is known that short maternal height does correlate with increased likelihood of short offspring.  This is partly mediated by having a small for gestational age birth.  Other limitations of the study included that the cohort was >90% Caucasian, and there was no adjustment for multiple births.

Useful links/references:

  • Growth Charts – Homepage -CDC growth charts
  • Pediatrics 2011; 128: e1187-94.  Growth and predictors of growth restraint in moderately preterm-born children.
  • Pediatrics 2003; 112: e30-8.  Growth of preterm infants during 1st 20 years.

NSAIDs and IBD

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While data has shown that nonsteroidal antiinflammatory drugs (NSAIDs) may worsen established IBD, whether these medications may serve as a trigger for IBD is less clear. One recent study indicates that NSAIDs may raise the risk of developing IBD (Ann Intern Med 2012; 156: 350-9).

This study examined the risk by using data from the Nurses Health Study which included 76,795 women.  Aspirin and NSAID use were self-reported.

Results:

  • “123 incident cases of CD and 117 cases of UC occurred over 18 years and 1,295,317 person-years of follow-up”
  • Frequent NSAIDs users (at least 15 days per month) had “increased risk for both CD (absolute difference in age-adjusted incidence, 6 cases per 100,000 person-years [95% CI, 0 to 13]; multivariate hazard ratio, 1.59 [CI, 0.99 to 2.56])”
  • And “UC (absolute difference, 7 cases per 100,000 person-years [CI, 1 to 12]; multivariate hazard ratio, 1.87 [CI, 1.16 to 2.99])”
  • There was no association with acetaminophen or aspirin within the same cohort.  This lessens the possibility of a false association; if subjects were treating GI symptoms, it is likely that an association would have been seen with all analgesics

The authors conclude that any absolute risk is low and therefore more important in understanding mechanism rather than in altering clinical use of these medications.

Link to abstract: Aspirin, nonsteroidal anti-inflammatory drug use, and risk for Crohn …

Additional NSAID references:

  • Gastroenterol 1966; 51: 430.  Sentinel article describing NSAID GI risk.
  • Gastroenterol 2008; 134: 1224.  Use of NSAIDs and risk prevention.
  • Clin Gastro & Hep 2007; 5: 1040. Long term effects of NSAIDs similar to COX-2 selective agents on small bowel mucosal damage (62% had abnormalities vs 50% of COX-2)
  • Clin Gastro & Hep 2006; 4: 1082 & 1090. Consensus on gastroprotection with NSAIDs.
  • Clin Gastro & Hep 2006; 4: 196.  NSAIDs worsen IBD.
  • Clin Gastro & Hep 2003; 1: 160.  Ileitis due to NSAIDs.

Why didn’t patient with documented reflux get better with PPI?

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There are numerous problems with pH studies; many of these problems have been alluded to in previous blog entries (see below).  Another problem is that these studies are not highly predictive of response to therapy (Gut 2012; 61: 501-506).

This French study from three centers examined 100 consecutive patients (58 females) with an average age of 50 years.  All patients had reflux symptoms, namely regurgitation and/or heartburn.  PPI dosage was not standardized and reflux symptoms were quantified with recall questionnaires.

The authors note that up to 40% of patients with reflux symptoms have inadequate symptom relief with a 4-week course of single dose proton pump inhibitor (PPI) therapy; the aim of their study was to investigate which factors on pH probe-impedance (pH-MII) would predict a response to therapy.

Definition: Nonresponders were patients who had more than 2 days of mild symptoms per week while receiving a standard or double dose of PPI treatment for 4 weeks

Results:

  • No reflux pattern on pH-MII was associated with a response to PPIs. Table 2 in the study looked at multiple factors including SI, SAP, time for acid exposure, and number of reflux events.
  • Lower BMI (≤ 25 kg/m-squared), non-erosive reflux, and normal pH study were associated with poor PPI response
  • Other factors associated with poor PPI response: female gender, irritable bowel syndrome (IBS), and functional dyspepsia.
  • Response rates: 58% of individuals with BMI >25, 71% with esophagitis, 23% with functional dyspepsia, 30% with IBS
  • Among responders, 77% were receiving a single dose PPI

Some of the poor response may be related to the study population.  Only 35% had abnormal acid exposure.  In total, 67% were determined to have abnormal pH studies, though this was due to a large fraction having a positive symptom-reflux association analysis.

However, this study population likely reflects a typical clinical group of patients diagnosed with GERD and demonstrates some of the shortcomings of pH-MII in clinical practice.  Even patients with abnormal pH-MII studies, the presence of functional dyspepsia and IBS were strongly associated with PPI failure.

Previous related blog entries:

HEROES trial

Impedance recommendations from PIG

Gastroesophageal Reflux: I know it when I see it

Treating reflux does not help asthma

Unexplained chest pain

Adding Methotrexate to anti-TNF therapy

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While new therapies are emerging for inflammatory bowel disease as noted in recent blog entries on Vedolizumab and Tofacitinib, many patients have refractory disease and require management with available treatments.  One strategy in this situation has been to add methotrexate (Inflamm Bowel Dis 2012; 18: 1488-92).

This case series from the Mayo clinic reported their experience with 14 pediatric Crohn’s patients (10 males) who had methotrexate added to anti-TNF therapy.

Clinical remission was achieved in 50% (PCDAI <15) within 6 weeks with methotrexate (dose: 15 mg/meter squared –average dose 17.5mg SC weekly).  All patients received folate supplementation (1 mg daily). In this study, the average duration of methotrexate use was only 8.2 months & average followup was only 10 months.

Discussion notes that prior to methotrexate all patients had active disease despite anti-TNF therapy & most had received thiopurines. Most patients tolerated methotrexate. Four patients had Clostridium difficile infection; two cases were de novo.  Even after treatment of the infection, patients with Clostridium difficile were refractory to methotrexate treatment.

Of the initial 14 patients, two patients had severe nausea; this resulted in medication discontinuation in one patient and dose reduction in another patient.  No liver or kidney toxicity was identified.

Patients who did not respond to methotrexate, subsequent care including the following: three had surgery, one received tacrolimus/corticosteroids, one received natalizumab, one received certolizumab, and one received adalimumab/corticosteroids (while awaiting screening for certolizumab).

A prospective study of methotrexate is needed to confirm the its effectiveness in refractory Crohn’s and to determine long-term safety and efficacy.

Patient information on methotrexate (from my office website):  Methotrexate

Related blog entries:

Drug levels for inflammatory bowel disease

Methotrexate and liver toxicity

Additional methotrexate references:

-IBD 2011; 17: 2521. Methotrexate therapy: ~25% remission at 1yr, 16% at 2yrs.. n=93.
-JPGN 2011;53: 389. n=64. Supports use of zofran for 1st few months to prevent nausea.
-JPGN 2010; 51: 714. Use of MTX after thiopurines. n=27. 48% in remission at 6 months.
-JPGN 2009; 48: 526. Use in pediatric CD, n=25. 64% response

Fontan and PLE

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In my practice, I am asked to give input on patients with Fontan procedure infrequently.  A few recent articles though are a good resource:

  • Nutr Clin Pract 2012; 27: 375-84
  • J Pediatr 2012;161:186-90

Both articles review the physiology and therapies available.  In essence, the Fontan operation establishes a passive connection between the systemic venous return and the pulmonary circulation.  When there are elevated inferior vena cava pressure, this can lead to hepatic dysfunction and protein-losing enteropathy.  The latter is related to engorged intestinal lymphatics, similar to that in congenital intestinal lymphangiectasia.  When lymphatic proteins leak, PLE only develops when the intestinal leak exceeds the patient’s ability to resynthesize lost proteins.

PLE presenting features: edema, diarrhea, bloating, pain, and pleural or pericardial effusions.  PLE places patient at risk for growth failure and associated problems. In more severe cases, hypocalcemia and infections due to lymphopenia can be present.

Potential treatments:

  • Agents that improve heart function -diuretics, pulmonary vasodilators (eg. sildenafil)
  • Corticosteroids including budesonide.  While improvement is common, hypoproteinemia returns after weaning of medication.  Systemic side effects occur even with budesonide.
  • Low molecular weight heparin.  Heparin likely helps by acting as a barrier to large molecules by improving the integrity of the basement membrane
  • Octreotide -has shown some effectiveness as an adjunct to other therapies in small studies
  • Albumin infusions
  • Diet: high protein (≥ 2 g/kg/day), low-fat (<25% of calories from fat), increase medium-chain triglycerides, & sodium-reduced
  • Surgical treatment (eg. atrial baffle fenestration) and cardiac transplantation

The second reference notes that many centers are delaying the Fontan procedure and accepting some degree of hypoxemia.  The problems with this approach include symptoms like headaches and decreased energy levels and the likelihood of developing pulmonary arteriovenous malformations.  Ultimately, the authors hypothesize that biomedical engineers may develop better solutions with miniaturized mechanical support devices to improve pulmonary blood flow.

Additional references:

  • Ann Thorac Surg 2010; 89: 837-42.  Budesonide for Fontan-associated PLE
  • Ann Thorac Surg 2011; 92: 1451-56.  Budesonide for Fontan-associated PLE
  • Congenit Heart Dis 2009; 4: 107-11.  Use of sildenafil for failing Fontan.

ELEVATE study

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Another clever acronym for the following:  Eltrombopag Evaluated for Its Ability to Overcome Thrombocyopenia and Enable Procedures (NEJM 2012; 367: 716-24).

Eltrombopag is an oral thrombopoietin-receptor agonist which is approved for use in chronic immune thrombocytopenia.

This double-blind, placebo-controlled trial evaluated whether eltrombopag increased platelet counts and reduced platelet transfusions in patients with chronic liver disease & platelet counts less than 50,000 per cubic millimeter.  145 patients received eltrombopag (75 mg once a day) and 147 received placebo.  Patients received therapy for 14 days. Elective procedures were scheduled no more than 5 days after the final dose of study medication (days 15 to 19).

Key findings:

  • Transfusions of platelets were reduced in the treatment group: 28% of patients compared with 81% in placebo group.
  • No differences in significant bleeding episodes noted.
  • Portal venous thrombosis was increased in treatment group with 6 patients compared with 1 patient in placebo group.

Study limitation: no standard practice with regard to use of platelet transfusions for thrombocytopenia (especially with platelet counts between 50,000-80,000)

Platelet transfusions can be problematic with cirrhosis.  Platelet transfusions have a short duration of efficacy, reactions to transfusions can occur, and multiple transfusions can result in antiplatelet antibodies. Nevertheless, the conclusions from this study: ‘until better identification of risk factors for the development of thrombosis…have been conducted, eltrombopag is not recommended as an alternative to platelet transfusion.’

TPN cycling

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A randomized prospective study of early parenteral nutrition cycling was not helpful in reducing parenteral nutrition associated cholestasis (PNAC): J Pediatr 2012; 161: 229-33.

This study enrolled preterm infants <1250 g in the first five postnatal days to either cycled (n=34) or continuous parenteral nutrition (n=36).  Cholestasis was defined as direct bilirubin >2 mg/dL. The study indicated that intralipid 20% was administered in all patients over 18 hours; the exact amount is not clear, though in the cycled group, patients received 3 g/kg/day on postnatal day 3.9 ± 2.6.  All patients received dextrose over 24 hours; only the amino acid (TrophAmine) infusion varied: 20 hours compared with 24 hours.

  • PNAC in each group was nearly identical, 32% vs 31% as were bilirubin and transaminase values.
  • While the study was randomized, the cycled group did have more frequent late-onset sepsis 22 (65%) compared with 14 (39%) which reached statistical significance.
  • In addition, a trend towards more frequent non-surgical NEC in cyclical group was noted as well: 6 (18%) compared with 3 (8%).
  • PNAC was associated with days until full enteral nutrition/duration of parenteral nutrition and bronchopulmonary dysplasia.

The higher incidence of late-onset sepsis could have occurred randomly and affected the results; alternatively, the higher rate could reflect an increased risk of sepsis due to doubling the frequency of central line access.

This study was  only powered to detect a 25% difference between the groups; the authors estimate that a study with 290 patients would be needed in each group to identify a reduction of 10% in the incidence of PNAC.  As such, this study leaves open the possibility that cycled parenteral nutrition may be helpful in a smaller percentage, particularly if efforts are made to eliminate central line infections.  More promising efforts to minimized PNAC are noted in previous blog entries:

PNAC, PNALD, and IFAC

Optimizing lipids to minimize cholestasis

More on PNAC

Four advances for intestinal failure

Electrons and Organic Food

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I still remember the Heisenberg uncertainty principle (Heisenberg states the uncertainty principle – PBS) from high school physics –thanks Mr. Pryor!  What quantum physicists don’t realize is that it is a leap of faith for anyone to believe in electrons much less to be concerned about measuring factors like speed or position.  I’ve never seen an electron but I’ve been convinced that they exist.

With organic foods, many people believe a health benefit exists, but does it and can it be proven?  A recent review weighs in (Ann Intern Med 2012; 157: 348-66) –thanks to Seth Marcus for pointing out this article.

This review from Stanford has been reported in multiple outlets and the soundbite is that organic foods are not better than conventional foods.  For example, the New York Times reports that the researchers “concluded that fruits and vegetables labeled organic were, on average, no more nutritious than their conventional counterparts, which tend to be far less expensive. Nor were they any less likely to be contaminated by dangerous bacteria like E. Coli.” Ultimately, “the researchers also found no obvious health advantages to organic meats.”

This is a vast oversimplification of this review.  So what did the researchers find and what were the limitations?

First –some background:

  • In 2010, U.S. sales of organic foods had increased to $26.7 billion; in contrast, only $3.6 billion was spent in 1997.
  • There are a number of different standards for organic foods, including U.S. Department of Agriculture (USDA), European Economic Community (EEC), and international federation of organic agriculture movement (IFOAM).
  • Typically organic foods are grown without synthetic pesticides or fertilizers or routine use of antibiotics/growth hormone.
  • Consumers often purchase organic foods due to concerns about effects of farming practices on environment, human health, animal welfare or perceptions of better taste.
  • Inclusion criteria for the cited reference allowed for 17 human studies and 223 nutrient/contamination studies of the initial 5908 potential relevant articles.

Key findings:

  • Conventional foods had 30% higher risk for pesticide contamination.
  • Conventional chicken and pork were more likely to have bacteria resistant to 3 or more antibiotics (33% risk difference).
  • Both organic and conventional products had frequent contamination with bacteria like Salmonella and Campylobacter.  Organic produce had higher risk for contamination with E. coli; this may have been due to some organic farms which used manure for fertilization.
  • There was not evidence that the organic foods were more nutritious.
  • Organic foods had higher levels of total phenols and ω-3 fatty acids.

Limitations:

  • No long-term studies of health outcomes have been performed.  The study with the longest duration included in this analysis was 2 years; the shortest was two days.
  • Variation in organic practices. Produce studies may not have reflected real-world organic practices.
  • Overall sample sizes were small (in total 13,806 human participants in 14 unique populations).
  • Reporting/publication bias.
  • Adherence with organic diets was varied; only 5 of the human studies evaluated participants who consumed a predominantly organic diet.

So, when one looks at this review, there are measurable differences in exposure to pesticides and antibiotic-resistant bacteria, despite variation in organic practices.  Specific nutrients are largely the same.  Whether any of these changes have a long-term health benefit is not known and would require an expensive long-term study to sort out.

 

One approach towards organic foods has been recommended by the Environmental Working Group.  They recommend “buying only organic when purchasing foods that contain the highest concentrations of pesticides, otherwise known as ‘the dirty dozen‘: peaches, strawberries, nectarines, apples, spinach, celery, pears, sweet bell peppers, cherries, potatoes, lettuce, and imported grapes” (Am J Clin Nutr 2010; 9 (suppl): 1499S-1505S).  This reference which discusses foods and potential hormonal effects on puberty goes on to state, “the biggest environmental exposure…is the ready availability of energy-dense foods” which contribute to obesity.

Related link:

Why are we seeing so many more cases

What do you know about the “exposome”?