Category Archives: Pediatric Gastroenterology Intestinal Disorder

TNF-α antagonists and infections

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In our pediatric patients who receive tumor necrosis factor-α (TNF-α) antagonists, fortunately we see few infectious complications.  In older patients, infections are much more important source of morbidity.  The main TNF-α inhibitors in clinical use include infliximab, etanercept, adalimumab, and certolizumab. Two large studies help quantify this risk:

  • Grijalva CG et al. JAMA 2011; 306: 2331-39.
  • Strangeld A et al. Ann Rheum Dis 2011; 70: 1914-20.

The first study assembled retrospective cohorts between 1998-2007 with rheumatoid arthritis (RA), inflammatory bowel disease (IBD), and psoriasis/psoriatic arthritis or ankylosing spondylitis (group 3).  This study’s acronym is SABER: Safety Assessment of Biologic Therapy. This data was compiled from 4 large US automated databases.  In total, there were 10,484 RA, 2323 IBD, and 3215 group 3 patients.  1172 serious infections were identified, mostly (53%) pneumonia or skin/soft tissue infections.  Among IBD patients, hospitalization rates were 10.91 (per 100 person-years) for TNF-α antagonists and 9.6 for comparison group.  The rates of hospitalization were similar in RA (8.16 with TNF-α antagonists) and lower in the group 3 patients (5.41 with TNF-α antagonists).   In all groups, baseline glucocorticoid use was associated with a dose-dependent increase in infections.  Overall, there was not an increase risk of hospitalizations with TNF-α antagonists compared with nonbiologic treatments.

The second cited reference examined patients from Germany with RA, enrolled in the RABBIT registry.  Data was available for 5044 patients.  There were 392 serious infections in this cohort with fewer infections noted after 3 years.  Risks for infection included age (>60), chronic lung or renal disease, history of serious infections, and treatment with glucocorticoids.  Treatment with 7.5-14mg conferred at relative risk (RR) of 2.1; treatment with ≥15mg conferred a RR of 4.7.  The rates of serious infections has an exponential change when risk factors are added together.  In Figure 3, estimated risk of serious infections for patients receiving ≥15mg  glucocorticoids along with three additional risk factors was 45% per year; with two risk factors the risk was approximately 20% and with one additional risk factor approximately 10%.

While these studies confirm significant risks of infections with biologic agents, the absolute risk is low particularly when other risk factors are not present.  In pediatric populations, glucocorticoids are the most prominent risk factor.  In addition, the risk of serious infections may be reduced by effective therapy.  In the SONIC study, serious infectious complications were less frequent in patients on combination therapy (infliximab and azathioprine) than with either monotherapy.  This result was likely due to the decreased need for glucocorticoids.

Additional references/relevant previous blogs:

  • NEJM 2010; 362: 1383. Sonic study. Combination AZA/IFX with greater efficacy. 56.8% remission in combo Rx.
  • -IBD 2008; 14: 721.  Pneumocystis jiroveci (carinii) w infliximab -review of 84 cases.  Dig Dis Sci 2007; 52: 1481-84.  PCP most likely to occur on average 3 weeks after 2nd infusion (possibly due to concommitant drug use)
  • -Gastroenterology 2008; 134: 929.  n=100 consecutive IBD patients with opportunistic infections.  Any of drugs associated w ~2.9 OR in adutls (greatest in >50yrs).  OR 14.5 when multiple immune drugs. Steroids more associated with Candida. AZA/6MP more with viral: HSV, VZV (shingles), CMV.  IFX less commonly with infections -though increased histoplasma and atypical mycobacterium
  • -Gastroenterology 2009; 136: 1182.  Review of biologics.
  • -IBD 2007; 13: 769.  Review of safety of wide range of biologics
  • –Clin Gastroenterol Hepatol. 2006; 5:621-30.  TREAT registry.  Steroids but not biologics associated with increased mortality risk.
  • Only one chance to make first impression

Look of improvement on an EoE diet

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In this month’s Gastroenterology, 50 adults with Eosinophilic esophagitis (EoE) were treated with a 6-food elimination diet (SFED) (Gastroenterology 2012; 142: 1451-1459).  Repeat endoscopy after 6 weeks determined responsiveness.  Histologic response was defined by having <5 eosinophils/high power fields (eos/hpf).  In 20 patients, reintroduction of foods followed by repeat endoscopy was undertaken.

After SFED, 32 (64%) had peak eosinophil counts <5 eos/hpf.  Symptom scores decreased in 94%.  After trigger food reintroduction, eosinophil counts returned to pretreatment values.  The changes are clearly visible in Figure 5.  The pictures are almost like the weight loss commercials on TV –striking improvement.  I contemplated putting in a scan of the Gastroenterology cover, but have not received permission from the publisher.  Check out this link to view it yourself:

http://download.journals.elsevierhealth.com/pdfs/journals/0016-5085/PIIS0016508512006257.pdf

Based on reintroduction, the foods most commonly associated with EoE were wheat (60%), and milk (50%).  Skin-prick testing predicted only 13% of foods associated with EoE.  In general, these study results mirror results from pediatric studies, with the exception that milk allergy has been found to be more common in some pediatric studies.

Only 20 patients completed the reintroduction process.  This process involved adding 1 food group every 2 weeks.  If the patient had symptoms during reintroduction or remained on regimen for 4 weeks, then  endoscopy with biopsies was performed.  If recurrence noted based on symptoms or histology, this required a 6 week washout before additional food reintroduction.  Of note, median time for recurrence of symptoms was 3 days after reintroduction.

Six foods: milk, wheat, eggs, soy, shellfish/fish, nuts.

This study shows that, as in children, adult EoE is predominantly a food-allergy disease

Related blog entries:

Eosinophilic Esophagitis -Six Food Group Diet

Guidelines for Eosinophilic Esophagitis

MicroRNA signature for eosinophilic esophagitis

The undiscovered country

Upper endoscopy useful for identifying Crohn’s disease

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In a large pediatric study, the value of upper endoscopy in detecting Crohn’s disease (CD) is evident (JPGN 2012: 54: 753-57).

While the majority of pediatric patients with suspected inflammatory bowel disease probably undergo both upper endoscopy and colonoscopy, the added value of upper endoscopy remains unclear.  In this retrospective study with 171 pediatric patients (70 with CD, 33 with UC, 68 Non-IBD), 11% of children with CD had the diagnosis established based “solely” on the finding of granulomatous inflammation in upper intestinal tract (along with clinical symptoms).

Other key findings:

  • Presence of histologic gastric inflammation in CD patients compared to control patients was significantly higher (p<0.0001) but not significantly higher compared to UC patients (p=0.19).
  • Duodenal inflammation was highly suggestive of CD compared with both UC and non-IBD patients.  This occurred in 19% of CD patients compared with 0% and 1% in the other groups respectively.
  • 21 children (30%) had granulomas identified in upper GI tract (19 in stomach).  In 8 (11%), the diagnosis was changed based on this finding.  Prior to histology, the tenative diagnosis: 2 UC, 4 IC, 2 non-IBD.
One curious finding was a the presence of “perianal abscess/fistula” with similar frequency in CD patients and UC patients based on their Table 2 Patient Characteristics.
Additional references:
  • -IBD 2009; 15: 1101-4.  Presence of UGI disease in IBD.
  • -JPGN 2007; 44: 653.  NASPGHAN report on discriminating/labelling UC vs. Crohn’s.
  • -JPGN 2002; 35: 636-40. Advocates panendoscopy for all new IBD.  Granulomas in 28% of EGDs & 71% of UC pts c some abnl on EGD; 82% Crohn’s c abnl EGD.
  • -JPGN 2005; 41: abstract 181 (page 549).  UGI identified granulomas in 15% that were not identified elsewhere.
  • -JPGN 2004; 39: 257-61. Diagnostic role of EGD for pediatric IBD.
  • Magnetic resonance enterography for Crohn’s disease

Test your knowledge of Clostridium difficile

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While Clostridium difficile (C diff) is a common infection, there is a lot to know.  A thorough but brief review is a good place to test your knowledge (Clin Gastroenterol Hepatol 2012; 10: 581-92).

  • a. When was C diff discovered?
  • b. When was C diff identified as a cause of antibiotic-associated diarrhea?
  • c. What antibiotics have been associated with a surge in severity and frequency of C diff infections?
  • d. Which C diff strains are the predominant cause of severe C diff?
  • e. How many C diff infections are occurring yearly in hospitalized patients in U.S.?
  • f. What are the most important risk factors?
  • g. How does the risk profile change for multiple antibiotics?
  • h. What time of year sees the greatest number of infections?
  • i. What does C diff smell like?
  • j. What % of antibiotic-associated diarrhea is due to C diff?
  • k. What clinical parameters may indicate severe infection and which ones indicate fulminant infection?
  • l. How much does a nucleic acid amplification test (NAAT) cost compare to enzyme immunoassay (EIA)?  How does this test work? What are the advantages/disadvantages?
  • m. How to treat severe infection?
  • n. What instructions should be given to prevent C diff in hospital?

Answers:

  • a. 1935
  • b. 1970s
  • c. Fluoroquinolones
  • d. BI/NAP1/027.  This strain has hypersecretion of toxins A & B, the presence of binary toxin, and resistance to fluoroquinolones.
  • e. CDI present in 300,000 hospitalized patients in 2005 (vs. 85,000 in 1993)
  • f. Hospitalization, older age (>65 years), and receipt of antibiotics (especially during 1st two months).
  • g. Hazard ratio 2.5 for two antibiotics, HR 9.6 for exposure to five antibiotics
  • h. Winter
  • i. “Horse stable”
  • j. 15-25%
  • k. Severe: WBC>15,000, Creatinine >1.5 fold patient’s baseline.  Also, albumin <2.5, admission to ICU, pseudomembranes on endoscopy, comorbid diseases.  Fulminant: (50% mortality) colon >6cm in diameter/toxic megacolon, WBC >50,000, lactate >5 mmol/L.
  • l. ~10 times the cost.  Works by identifying genes that encode toxins by PCR or loop-mediated amplification of DNA.  Test is very sensitive and rapid but may have false-positives.  Some recommend using a less expensive test for screening to decrease costs.
  • m. Vancomycin up to 500mg QID (NG/PO) plus metronidazole.  If complete ileus, vancomycin can be given rectally
  • n. Hand hygiene (not alcohol): either soap or chlorhexidine, contact precautions, cleaning environment –chlorine solutions effective (1000-5000 ppm), antimicrobial stewardship (especially reducing clindamycin and fluoroquinolones)

How many did you get right?

Related posts:

Clostridium difficile -Current Battlelines

Proton pump inhibitors–infection risk with cirrhosis

Colonic disease and PSC

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While primary sclerosing cholangitis (PSC) has been associated with inflammatory bowel disease, and ulcerative colitis (UC) in particular, the pathogenesis of this relationship has not been established.  A fascinating observation on this relationship is that an inflamed colon is important in PSC development (Clin Gastroenterol Hepatol 2012; 10: 439-41).

In this study which reviewed 2754 Irish patients with IBD, 59 (2.2%) had PSC.  PSC incidence correlated with increasing colonic involvement.  Among the 13 patients with Crohn’s disease, none had isolated small bowel disease.  The second part of the study involved a review of 82 separate PSC patients attending the Irish National liver transplant unit.  The majority of ulcerative colitis patients had a pancolitis; all 10 PSC patients with Crohn’s disease had colonic involvement.

Since PSC occurs without IBD, colonic inflammation is not necessary for PSC development.  However, in patients with IBD, colonic inflammation is very important.  In fact, in a previous study of 53 PSC-IBD patients, no UC patient status post a colectomy had recurrent liver disease following liver transplantation whereas seven patients with intact colons had recurrent disease following liver transplantation.

The authors speculate that bacterial translocation along with subsequent portal bacteremia may be an important step in pathogenesis among these patients.

Additional references/previous posts:

Salmonella by mail-order

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Sometimes patients are amazed that hemoccult cards can be sent by mail.  Now, I learned something new: you can mail-order live poultry and thereby spread salmonella far and wide (NEJM 2012; 366: 2065-73).  This study identified 316 cases in 43 states.

Key findings:

  • 36 hospitalized (23%)
  • 38 had chicks as pets (42%); of these, 22 (69%) said the pet owner was a child <5 years
  • Salmonella enterica serotype Montevideo subtype
  • 81% of infections identified as coming from a hatchery in Western U.S.
  • After identification of problem, owners implemented recommendations which lowered salmonella contamination.  After these measures, outbreak strain still detected in 7% of samples
  • Hatcheries mail live poultry to all 50 states –4 million birds are produced annually for this purpose. Approximately 250,000 birds are shipped each week, usually within 24 hours of hatching; each costing about $5 each.

Because only a portion of salmonella infections are identified with laboratory tests, there are likely thousands more infections associated with this outbreak.  Overall, nontyphoidal salmonella infections are estimated to cause 1 million illnesses, 19,000 hospitalizations, and 370 deaths annually.  Most infections are acquired as foodborne illnesses.  Though contact with animals, as this report indicates, is another mechanism.  These birds can appear healthy and intermittently shed salmonella.

Individuals wishing to reduce their risk of illness should practice careful hand hygiene around animals.  See link for helpful advice:

http://www.cdc.gov/healthypets/resources/salmonella-baby-poultry.pdf

The poultry business can help by adhering to sanitary practices, by avoiding artificially coloring chicks (which targets children), and by warning recipients of the danger of salmonella infection.

Food choices, FODMAPs, and gluten haters

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Given the frequency of functional gastrointestinal diseases (FGID), including irritable bowel syndrome (IBS), dietary treatments that may improve symptoms receive a lot of attention.  A recent review of the role of food choices in the development and management of FGIDs is a useful reference (Am J Gastroenterol 2012; 107: 657-66 -thanks to Ben Gold for forwarding this article).

This review details specific dietary advice as well as the following specific physiologic effects of FODMAPs:

  • Osmotic effects
  • Bacterial fermentation
  • Motility effects
  • Prebiotic effects
  • Systemic effects –mild depression, tiredness
In addition, the review looks at other potential foods which could serve as a trigger for IBS symptoms, like gluten & summarizes why some IBS patients are gluten haters.  The authors acknowledge that gluten sensitivity, in the absence of celiac disease, does not have a known mechanism.  Until a reliable marker becomes available, the importance of gluten sensitivity for FGIDs is unknown.
Related posts:

What to make of FODMAPs

Gluten sensitivity without celiac disease

Is a biopsy necessary in Celiac disease?

New caustic danger from detergent pods

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“Brightly colored little packets that combine laundry detergent with other cleaning agents are a new convenience for consumers — and a new danger for kids.”

See more complete story at attached links that follow:

http://www.washingtonpost.com/national/poison-control-centers-field-increased-number-of-calls-of-children-ingesting-detergent-packets/2012/05/24/gJQAaiSZnU_story.html

http://yourlife.usatoday.com/health/healthyperspective/post/2012-05-24/new-kid-danger-swallowing-candy-colored-laundry-packets/701134/1

Does pancreas divisum cause pancreatitis?

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The role of pancreas divisum (PD) as a cause of either acute recurrent or chronic pancreatitis (AR/CP) remains a matter of debate.  A recent study suggests that pancreas divisum serves as a cofactor but does not cause pancreatitis independently (Am J Gastroenterol 2012; 107: 311-17).

PD occurs due to failure of fusion of the dorsal and ventral pancreatic buds during gestation.  The frequency of PD has been estimated to be between 5-10% of the general population based on large post-mortem studies.  There is an increased frequency of PD in patients with idiopathic pancreatitis (12-26%).  The referenced study from France examined the frequency of genetic mutations vis-a-vis relationship with PD.  PD was determined using MRCP.

Findings–percentage with PD among subgroups:

  • 7% of subjects without pancreatic disease, n=45
  • 7% of alcohol-associated pancreatitis patients, n=29
  • 5% of idiopathic pancreatitis patients, n=40
  • 16% of patients with PRSS-1-associated pancreatitis, n=19
  • 16% of patients with SPINK-1-associated pancreatitis, n=25
  • 47% of patients with CFTR-associated pancreatitis, n=30

The study has several limitations.  Overall, the numbers of patients with pancreatitis are fairly low.  In addition, these genetic mutations are not typically examined in individuals without pancreatitis.  As such, the effect of these mutations with PD still is difficult to know in comparison to a larger population.

Additional references:

  • Recurrent pancreatitis and genetic underpinnings (previous blog post)
  • -Clin Gastro & Hep 2009; 7:141.  Review -case of recurrent pancreatitis -suggests checking ANA, Trig, IgG4 (also TTG)
  • – J Pediatr 2008; 152: 106.  Acute pancreatitis in young children; 109 cases.  systemic dz in 29, drugs in 7, gallstones in 3, annular pancreas in 1, trauma in 7, infections in 16, CF in 2, Idiopathic in 15.
  • -NEJM 2006; 354: 2142.  Review of acute pancreatitis mgt.
  • -Clin Gastro & Hep 2006; 4: 455.  Elevated pancreatic enzymes frequently identified in celiac disease.
  • -Clin Gastro & Hep 2007; 5: 1347. Celiac is a risk factor for acute & chronic pancreatitis. n=14,239 & 69,381 reference population (Sweden).
  • -Pediatrics 2005; 115: e463. CF & pancreatitis
  • -JPGN 2003; 37: 5591. Systemic dz 14%, Trauma 14%, drugs 12%, metabolic 6%, structural 5%, infectious 8%, ERCP 6%, Biliary 12%, Familial 3% (but accounted for 20% of episodes) Transplant 8%, idiopathic 8%
  • -Clin Perspectives in Gastro 2002; 5: 73. Pancreas divisum

Quantifying Risk of PML with Natalizumab

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Given the limited number of treatment options for inflammatory bowel disease, when Natalizumab became available, there was a great deal of enthusiasm.  This quickly diminished as reports of progressive multifocal leukoencephalopathy (PML) emerged.  So far, I have not prescribed this agent.

Due to its efficacy for multiple sclerosis and IBD, there has been continued interest in understanding the risk for PML (NEJM 2012; 366: 1870-80, editorial pg 1938-39).

Key findings:

  • 212 cases of PML among 99,571 patients treated with natalizumab (2.1 cases per 1000)
  • Three main risk factors: positive JC-virus antibody, previous use of immunosuppressants, and receiving natalizumab more than 2 years

Patients who were negative for anti-JC virus antibodies had an incidence of 0.09 cases or less per 1000 patients.  Among patients who test positive for anti-JC virus antibodies, the risk remained <1 per 1000 patients if no use of immunosuppressants and 2 per 1000 if prior use of immunosuppressants during the first two years of therapy.  The risks were five-fold higher after 2 years in both groups.

While the risks are becoming more clear, the benefits of natalizumab are fairly well-established for multiple sclerosis.  Natalizumab decreased the annualized rate of relapse among patients with relapsing–remitting multiple sclerosis by 68%.

Additional references:

  • -NEJM 2009; 361: 1067, 1075, 1081.  Asymptomatic detection of JC virus common in urine noted in patients Rx’d with natalizumab (19% baseline to 63% on Rx); actual leukoencephalopathy ~1/1000 patients.
  • -Gastroenterol 2007; 132: 1672.  ENCORE trial.
  • -JPGN 2007; 44: 185. n=31 children/adolescents.  55% response, 29% remission; dosed at 3mg/kg.
  • -IBD 2007; 13: 2.  n=79.  Trial of combination natalizumab & infliximab.
  • -NEJM 2006; 354: 899, 911, 924.  Natalizumab slows progression of MS.  Risk of PML due to JC virus 1:1000 in 18 months of Rx.
  • -NEJM 2005; 353: 1912/1965.  Natalizumab not significantly effective for Crohn’s in this study
  • -NEJM 2005; 353: 362, 369, 375, 414.  3 cases of PML associated with Natalizumab
  • -JPGN 2004; 39: S49 [abstract 0107].  Natalizumab in 38 adolescents was effective (Hyams et al).
  • -Gastroenterol 2004; 126: 1574-81. review.  Natalizumab benefitted subjects with elevated CRP. (dosing 300mg every 4 weeks.)
  • -NEJM 2003; 24-32 & 68.  Natalizumab improved response rates in pts c Crohn’s dz (similar to infliximab).  Drug blocks alpha4 integrins which are required for lymphocytes to enter the intestine.
  • -Gastroenterol 2001; 121: 268-74. Infusion of 3mg/kg decreases CDAI in Crohn’s dz.