Microparticles and Pediatric IBD

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Before reading a recent publication (JPGN 2013; 56: 401-07), I was not aware of microparticles; microparticles may play an important role in the development of venous thromboembolism (VTE).  Pediatric patients with inflammatory bowel disease (IBD) have a higher relative risk of VTE compared to their peers than individuals >60 years of age, though the absolute risk is low.  Much of the pathophysiology underlying the increased VTE risk remain uncertain.

Microparticles have been called “platelet dust” and are microvesicles that are released from the plasma membrane of many cells (leukocytes, red blood cells, endothelial cells, and platelets).

This study examined plasma samples from 33 pediatric patients with Crohn disease (CD), 20 pediatric patients with ulcerative colitis (UC), and 60 healthy controls. Subsequently, microparticles’ procoagulant activity was measured.  The CD and UC patients were consecutively enrolled from the outpatient clinic.  Only 3 patients in each IBD group was receiving a biologic therapy (infliximab). The disease activity and extent were compared with measures of procoagulant activity.

Several assays were undertaken to assess microparticles and thrombin generation. Key findings:

  • Increased procoagulant function of microparticles was identified in all CD patients (active and quiescent) and in UC patients with active disease.
  • A positive correlation was found between disease activity scores and procoagulant activity.

The authors note that elevated microparticles “may play a role in inflammation.” Inflammation and coagulation likely influence each other.  The authors note that VTE risk is greatest during flares but is still increased in patients in remission compared with controls.

The authors do not discuss the relationship of mucosal healing to microparticles or VTE. However, given that clinical remission is not defined currently based on mucosal healing, it would be of interest to know the status of these microparticles and the risk of VTE with mucosal healing. Perhaps the “quiescent” CD patients have ongoing disease contributing to their increased risk of VTE and increased procoagulation function of microparticles.

Related blog entry:

VTE with IBD | gutsandgrowth

**According to previous expert consensus guidelines, “routine heparin prophylaxis cannot be justified in children until better evidence is available to suggest that the benefit outweigh the risks”  (Turner D, et al. Am J Gastroenterol 2011; 106: 574-88).

For the pediatric pancreatologists

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Pancreatitis is a terrible affliction whether acute, recurrent or chronic.  While pediatric patients often have “mild” problems from acute pancreatitis, even in these cases the pain is usually severe and the treatment, which consists mainly of holding feedings and providing pain relief, does not impress anyone.

A few recent references do provide more data on several aspects of pancreatitis.

The first reference, J Pediatr 2013; 162: 788-92, provides data on the rare problem of acute necrotizing pancreatitis in children.  This retrospective study encompassing 21 years identified seven children.  CT scan showed necrosis of more than 30% and/or more than a 3 cm area in all of these patients.  Etiologies included medications (L-asparaginase, Valproate, Minocycline), diabetes (n=1), and gallstones (n=1).  No patients needed surgery or died.  After discharge, 5 patients had complications which included pseudocysts, diabetes, and pancreatic exocrine insufficiency.

Key points:

  • CT scan (with contrast) is useful in diagnosis and assessment of severity.
  • Initial presentation is similar to cases of acute pancreatitis without necrosis.  Long-term complications are increased.

The second reference: Gastroenterol 2013; 144; issue 6.  The entire issue is devoted to pancreas issues.  Pages 1272-81 review acute pancreatitis, pages 1282-91 review chronic pancreatitis, and pages 1292-1302 review genetic risk factors.

Page 1288 provides a suggested management algorithm for chronic pancreatitis:

Medical therapy recommendations include alcohol/smoking cessation, counsel regarding nutrition/vitamin D/calcium, consider analgesics (start with tramadol), consider adjuncts for pain (e.g.. neuron tin, SSRI, SSNRI, TCAs), assess exocrine and endocrine function (elastase and HgbA1C), use steroids if autoimmune pancreatitis.

If medical therapy ineffective, assessment of pancreatic duct is recommended.  Based on this information, discussion of endoscopic and surgical treatment is outlined as well.

Related blog entries:

Foil PNALD with FOLE?

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As noted on previous blog entries (see below), there has been significant enthusiasm for fish oil based lipid emulsion (FOLE) despite a lack of data showing superiority compared with standard soy-based lipid emulsions at similar dosing.  More data for FOLE helping infants with cholestasis are available (J Pediatr 2013; 162: 793-8).

Design: Single center, prospective observational study of 57 infants with parenteral nutrition-associated liver disease (PNALD) which  took place between 2007-2011.  All infants were between 2 weeks and 6 months of age at enrollment.  At enrollment, FOLE (Omegaven) at a dose of 1 g/kg/d was infused over 24 hrs.  FOLE which is not FDA-approved is available on a compassionate use protocol.

Infant characteristics: Median gestational age: 28 weeks. 47 of 57 were long-term survivors.  The median time at initiation of FOLE was 39.3 weeks post-menstrual age.

Results:

  • Median conjugated bilirubin at initiation of FOLE therapy was 7.5 mg/dL.
  • Resolution of cholestasis occurred at a median of 35 days (range 7-129) after starting FOLE.  Longer times for resolution were noted in those with higher initial bilirubin.
  • Time to resolution was inversely proportional to gestational age at birth (p=0.02) and directly to time to receive 100% calories enterally (p=0.03)

The authors note that none of the infants who died had liver failure; most deaths were due to multi-organ failure and sepsis.

In the discussion, the authors state “the most significant finding from this study is the effectiveness of FOLE in resolving cholestasis irrespective of the initial serum bilirubin values.”  I take issue with this statement primarily because the design of the study does not allow such attribution.  Without a randomized trial comparing FOLE to standard intralipids, this statement overstates any conclusion that can be drawn from this study.  Given the fact that resolution was correlated with advancement of enteral feedings, it is plausible that a similar result would occur with standard intralipids.

The authors make a number of other speculations about the potential superiority of FOLE over standard soy-based lipid emulsions, but concede that “our study was not adequately equipped to address” the association of reduced intralipid with improvement in cholestasis.  Despite this concession, the authors boldly proclaim in the concluding paragraph: “while awaiting the more general availability of FOLE, infants at high risk should be identified early and referred to centers that provide the option of FOLE…in which families are fully informed of both the potential benefits and limited current data.”

A recent media report also promotes the effectiveness of FOLE: http://nbcnews.to/11vbL2E 

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“Tummy Time” Not Needed

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A recent NY Times article reviews a study which showed no benefit in motor development in babies who had “tummy time.”

Here’s the link: nyti.ms/11vrG11 

Here’s an excerpt:

Putting infants to sleep on their backs, recommended since the early 1990s, has helped reduce the prevalence of sudden infant death syndrome. ..Now a new study, published in May in the journal Early Human Development, suggests that tummy time may be irrelevant.

Canadian researchers compared 1,114 infants born from 1990 to 1992, just before the “back to sleep” campaign began, with 351 infants born 20 years later. They found no difference between the two groups in the age at which prone to supine or supine to prone rolling began, or in the order in which those behaviors appeared….

Whether tummy time helps or not, said the lead author, Johanna Darrah, a pediatric physical therapist at the University of Alberta, “the back to sleep campaign has not adversely affected motor development. Motor development happens.”

Codeine Contraindicated after Adenotonsillectomy

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Due to concerns outlined previously (Why “therapeutic dose” of codeine can kill | gutsandgrowth), the FDA has now placed a boxed warning on all codeine-containing products and is now contraindicated after adenotonsillectomy.  This is reviewed in a recent perspective article: NEJM 2013; 368: 2155-57.

“In the case of codeine, a combination of case reporting and our evolving understanding of genetic influences on drug response has clarified the need to avoid this drug after adenotonsillectomy.”

Bottomline: Due to the variability in codeine metabolism, alternative narcotic agents are usually a better choice even in those who have not undergone adenotonsillectomy.

High Rates of Helicobacter Pylori Resistance

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While the development of antibacterial resistance has broad implications, in gastroenterology patients specific problems have emerged with Helicobacter pylori (H pylori) and this has led to changes in first-line therapy( ).  More data on the treatment resistant H pylori has been published (JPGN 2013; 56: 645-48).

77 consecutive strains of H pylori  from Brazilian children and adolescents were isolated from gastric biopsies and analyzed; this study took place between 2008-2009 and the mean age was 11.1 years.  In 71 strains, there were no previous attempts at eradication.

Results:

  • 40% of strains were resistant to metronidazole
  • 19.5% of strains were resistant to clarithromycin
  • 10.4% of strains were resistant to amoxicillin
  • All strains were susceptible to furazolidone and tetracycline
  • 14/77 (18.2%) patients had multiple resistances

Take-home point: Resistance to antibiotics is altering our approach to H pylori therapy.  Antibiotic susceptibility testing may be needed to improve antibiotic selection and eradication rates.

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Switching from Thiopurines to Methotrexate

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Data regarding methotrexate treatment for Crohn’s disease (CD) is limited.  A fairly large retrospective study provides a better idea about its effectiveness over a five-year period (Clin Gastroenterol Hepatol 2013; 11: 667-72).

In total 174 consecutive CD patients (age 35 ±12 y) from 3 hospitals were analyzed.  All of these patients received methotrexate (MTX) after thiopurine therapy. 23% had not responded to an anti-TNF agent.  Most of the patients who had failed thiopurine treatment had an intolerance to thiopurine rather than loss of clinical response.  Data on patient characteristics including smoking status, disease behavior/location, previous treatments, and indication for MTX are detailed in Table 2.  Interestingly, 113 patients were female.  The authors noted that 90% of their patients received MTX parenterally.

Key findings:

  • Patients with sustained clinical benefits from methotrexate monotherapy:  98 (86%) at 6 months, 50 (63%) at 12 months, 27 (47%) at 24 months, and 3 (20%) at 60 months.
  • 45 (26%) discontinue methotrexate due to intolerance, mostly within the first 6 months.  However, adverse effects were generally mild.  Only one patient required hospital admission for an infection (cytomegalovirus).

There are many limitations of this retrospective study.  Nevertheless, a significant portion of patients derived clinical benefit for at least 2 years.

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Neurological Complications Associated with Inflammatory Bowel Disease

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Though I have not seen much in the way of neurological complications in our pediatric inflammatory bowel disease (IBD) population, nevertheless I worry about them.  A recent article provides some insight into the incidence, the pathophysiology and approach to these complications (Inflamm Bowel Dis 2013; 19: 864-72).

Types of neurologic complications: The most common neurologic complication is peripheral neuropathy.  The frequency is quite variable based on data collection method.  In large administrative healthcare data, the prevalence has been reported around 2% whereas in cohort studies the range has been 8-15%. Other complications include meylopathy, cerbrovascular disease, cranial nerve palsy (eg. Melkersson-Rosenthal syndrome), seizures, and demyelinating diseases.

With regard to demyelinating diseases, this has gained additional attention in the setting of biologic agents which have been associated with this complication.  However, the authors note that a pre-biologic treatment study from Olmstead County, observed a prevalence of multiple sclerosis of 1% which was 3.7 times higher than expected.  In addition, similar studies have confirmed this finding.

Potential mechanisms vary greatly depending on the neurologic complication. With regard to cerebrovascular disorders, “venous thromboembolism (VTE) has been shown to occur 3 times more frequently in patients with IBD (the risk increases to 8-10-fold in patients with active colitis) than the general population.”  Hence, VTE prophylaxis is recommended by the authors in hospitalized IBD patients, especially if they are experiencing a disease exacerbation.

In addition to the underlying disease, vitamin deficiencies (eg. Vitamin B12) and medications can trigger neurologic complications.

  • Natalizumab: progress multifocal leukoencephalopathy (PML)
  • Metronidazole: peripheral neuropathy (typically reversible with drug discontinuation)
  • Anti-TNF-α agents (infliximab, adalimumab, certolizumab): demyelination, rarely seizures, and rarely PML
  • Cyclosporine: various neurotoxicity in ~25%

Related blog entries:

Gluten-related Disorders

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For those who missed a recent NASPGHAN Foundation webinar, I’ve attached two links (with permission from NASPGHAN foundation):

1. The PDF of the slides –these are very useful:

NASPGHAN GlutenWebinar 6_5_13 Final v34

2. Link to webinar, including CME:

http://limelightdc.com/clientarea/naspghan_gluten_webinar_06_13/landing_page.html

The experts provide a useful review of celiac, wheat allergy, and wheat intolerance.  For celiac screening, the webinar recommends avoiding a panel of serology tests in favor of isolated Tissue Transglutaminase IgA Antibody (possibly with serum IgA level.

Related blog links:

Live longer -don’t take your vitamins?

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A recent editorial by Paul Offit provides data that taking more vitamins than your daily requirement is more likely to increase your risk of cancer and death (this has been noted on this blog as well –see related links below).

Link: nyti.ms/1bhK2Eg 

Here is an excerpt:

…last year, a Cochrane review found that “beta carotene and vitamin E seem to increase mortality, and so may higher doses of vitamin A.”

What explains this connection between supplemental vitamins and increased rates of cancer and mortality? The key word is antioxidants.

Antioxidation vs. oxidation has been billed as a contest between good and evil. It takes place in cellular organelles called mitochondria, where the body converts food to energy — a process that requires oxygen (oxidation). One consequence of oxidation is the generation of atomic scavengers called free radicals (evil). Free radicals can damage DNA, cell membranes and the lining of arteries; not surprisingly, they’ve been linked to aging, cancer and heart disease.

To neutralize free radicals, the body makes antioxidants (good). Antioxidants can also be found in fruits and vegetables, specifically in selenium, beta carotene and vitamins A, C and E. Some studies have shown that people who eat more fruits and vegetables have a lower incidence of cancer and heart disease and live longer. The logic is obvious. If fruits and vegetables contain antioxidants, and people who eat fruits and vegetables are healthier, then people who take supplemental antioxidants should also be healthier. It hasn’t worked out that way.

The likely explanation is that free radicals aren’t as evil as advertised. (In fact, people need them to kill bacteria and eliminate new cancer cells.) And when people take large doses of antioxidants in the form of supplemental vitamins, the balance between free radical production and destruction might tip too much in one direction, causing an unnatural state where the immune system is less able to kill harmful invaders. Researchers call this the antioxidant paradox.

In December 1972, concerned that people were consuming larger and larger quantities of vitamins, the F.D.A. announced a plan to regulate vitamin supplements containing more than 150 percent of the recommended daily allowance. Vitamin makers would now have to prove that these “megavitamins” were safe before selling them. Not surprisingly, the vitamin industry saw this as a threat, and set out to destroy the bill. In the end, it did far more than that.

Industry executives recruited William Proxmire, a Democratic senator from Wisconsin, to introduce a bill preventing the F.D.A. from regulating megavitamins. On Aug. 14, 1974, the hearing began.

Speaking in support of F.D.A. regulation was Marsha Cohen, a lawyer with the Consumers Union. Setting eight cantaloupes in front of her, she said, “You would need to eat eight cantaloupes — a good source of vitamin C — to take in barely 1,000 milligrams of vitamin C. But just these two little pills, easy to swallow, contain the same amount.” She warned that if the legislation passed, “one tablet would contain as much vitamin C as all of these cantaloupes, or even twice, thrice or 20 times that amount. And there would be no protective satiety level.” Ms. Cohen was pointing out the industry’s Achilles’ heel: ingesting large quantities of vitamins is unnatural, the opposite of what manufacturers were promoting.

A little more than a month later, Mr. Proxmire’s bill passed by a vote of 81 to 10. In 1976, it became law. Decades later, Peter Barton Hutt, chief counsel to the F.D.A., wrote that “it was the most humiliating defeat” in the agency’s history.

As a result, consumers don’t know that taking megavitamins could increase their risk of cancer and heart disease and shorten their lives; they don’t know that they have been suffering too much of a good thing for too long.

Paul A. Offit is the chief of the infectious diseases division of the Children’s Hospital of Philadelphia and the author of the forthcoming book “Do You Believe in Magic?: The Sense and Nonsense of Alternative Medicine.”

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