Tag Archives: IBD

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:

VTE with IBD

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In our children’s hospital, work is underway to systematically screen children for risk factors for venous thromboembolism (VTE) and to establish an algorithm to lower the risk of a VTE with either mechanical or pharmacologic treatments. One of the risk factors has been the presence of inflammatory bowel disease (IBD).  The absolute risk of IBD for VTE is not clear.  However, a recent study relates the risk among a large Danish population of adults and children (Gut 2011; 60: 937-43).

The study included 49,799 patients with IBD (14,211 Crohn’s, 35,229 UC) and compared with 477,504 members of the general population.  VTE risk for IBD was increased with HR of 2.0.  The incidence of VTE increased with age; however, the RR was higher in younger patients.  Among those less than 20 years, HR was 6.6 for VTE; HR 6.0 for DVT and 6.4 for PE.  In this age group, “unprovoked” VTE had HR of 4.5.  Unprovoked VTE was defined as event occurring without malignancy, recent surgery, pregnancy or fracture.

Although the relative risk is increased, the authors caution that the absolute risk in younger patients is low.  In those IBD patients less than 20 years, the incidence rate was 8.9 per 10,000 person years.  In contrast, in those IBD patients older than 60, the incidence rate was 54.6 per 10,000 person years.  There did not seem to be a significant difference between Crohn’s disease and ulcerative colitis in absolute or relative risk. The authors conclude that in those IBD patients younger than 20 years without ‘other VTE risk factors or limited mobility, the benefits of prophylaxis may no longer outweigh the risks.”  In older patients (>60 years), even outpatients experiencing flares might benefit from VTE prophylaxis.

Additional references:

  • -NEJM 2012; 366: 860 (letter to editor). Authors emphasize importance of VTE with UC, especially during flares.
  • -Lancet 2010; 375: 657-63. VTE with active IBD and in remission.
  • -Clin Gastroenterol Hepatol 2008; 6: 41-5. Thrombosis with IBD.
  • -Gut 2004; 53: 542-8. IBD -risk factor for VTE?
  • -Gut 2004; 53 (suppl 5): v1-16. IBD guidelines for management.

Can I go?

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How safe is it for IBD patients to travel?  A retrospective study from adult patients with IBD (n=222) compared with controls (n=224) indicates that the risk of travel for IBD patients is only a little more than the general population (Clin Gastroenterol Hepatol 2012; 10: 160-65).

IBD patients with an average age of 37 years had infections during 15% of trips compared with 11% for controls.  92% of infections were due to enteric disease. However, this increased risk was identified in travel to industrialized countries not to developing countries.  This likely indicates that much of the increase is due to IBD flares rather than increased susceptibility to infections.  Nearly half of patients in this study were receiving immunosuppression: immunomodulators 29%, biologics 5%, dual therapy 6%, or corticosteroids 4%.  Not surprisingly, patients with increased IBD flares (OR 1.9) and IBD-related hospitalizations (OR 3.5) represent a group with higher risk for illness.  Most illnesses were mild & self-resolving in a few days.  Only five IBD patients required hospitalization for the following: dehydration, perianal abscess, malaria, flare, & small bowel obstruction).

Additional references:

  • -Clin Gastro & Hep 2010; 8: 490. Review of traveler’s diarrhea. Recs pepto if emesis, rifaximin or cipro or azithromycin if watery diarrhea, azithromycin if bloody diarrhea
  • -Clin Gastro & Hep 2007; 5: 451. Use of rifaximin (200mg tid)-loperamide provided rapid improvement.
  • -NEJM 2006; 354; 119. Traveler’s diarrhea.
  • -NEJM 2002; 347: 505.  Illness after travel.
  • -www.cdc.gov/travel/index.htm

Why are we seeing so many more cases

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In this month’s Gastroenterology, two articles offer some insight into this question for two separate problems.

With regard to inflammatory bowel disease, (IBD) –both Crohn’s disease and UC –there is an increasing prevalence and incidence worldwide (Gastroenterology 2012; 142: 46-54). This article identified 8444 previous citations and then identified 262 studies with relevant data.  Overall, the highest incidence and prevalence of these disorders occurs in Europe and North America.  In North America, Canada has the highest prevalence with 0.6% of the population having IBD.

After going through the statistics, the authors offer some discussion on why IBD is increasing.  In the developing parts of the world, some of the increase is due to the ability to detect and differentiate these disorders due to improving access to medical care/colonoscopy.  In the areas of the world with the highest incidence/prevalence, environmental risk factors are playing an important role.  Potential factors include microbial exposures, sanitation, lifestyle behaviors, medications, and pollution.  These factors are supported by other epidemiological studies which show that individuals who move from low prevalence areas to higher ones are at increased risk for IBD, especially among first generation children (Gut 2008; 57: 1185-91).  Furthermore, in low prevalence regions, IBD is increasing with more industrialization (Chin J Dig Dis 2005; 6: 175-81, Indian J Gastroenterol 2005; 24: 23-24.)  Exact mechanisms are poorly understood; however, even in the U.S. it is recognized that rural/farm exposure at a young age reduces the likelihood of developing IBD at a later age (Pediatrics 2007; 120: 354).

Celiac disease, likewise, has seen an increase in prevalence.  With celiac disease, the proliferation of widely available and more accurate serology has been crucial in the identification of more patients.  However, like IBD, there is likely a role for changing microbial environment contributing to an increasing case burden.  Recently, reports have shown that the risk of celiac disease can be influenced at birth (Gastroenterology 2012; 142: 39-45).  Although the absolute risk was modest, there was an increased risk demonstrated with elective but not emergent cesarean delivery among a large nationwide case-control study from Sweden.  Among the cohort of 11,749 offspring with biopsy-proven celiac (with matched control group of 53,887), elective cesarean delivery resulted in an odds ratio of 1.15 (confidence intervals 1.04-1.26).  This study confirmed other studies which have shown an increased risk with cesarean delivery (Pediatrics 2010; 125: e1433-e1440).  Some of the strengths of this Swedish study, included the fact that the deliveries were separated based on elective or emergency cesarean delivery and were controlled for whether the mother had celiac disease.  (Pregnant women with celiac disease have an increased risk of cesarean delivery.)  The authors speculate that the reason why elective cesarean deliveries increase the risk of celiac disease is that microbial exposures at birth likely influences perinatal colonization –>affects intestinal immune response and mucosal barrier function. Offspring of women with emergency cesarean delivery would be more likely to be exposed to bacteria from the birth canal and no significant increase risk of celiac disease could be identified in this group.

Thus how we are born and where we live make a big impact on the likelihood of developing these GI disorders.

Additional References:

  • -Gut 2011; 60: 49-54. n=577,627 Danish children. Use of antibiotics associated with increase risk of Crohn’s disease (but not UC), especially at younger ages (3-11month of age, & 2-3yrs of age). Each course increased risk by 18%. In children with >7 courses, relative risk was 7.3. especially penicillins.
  • -NEJM 2011; 364: 701, 769. Living on a farm decreases risk of childhood asthma.
  • -Nature 2011; 476: 393. ‘Stop killing beneficial bacteria.’  For example, killing H pylori likely increases risk of esophageal adenocarcinoma
  • -Gastroenterology 2011; 141: 28, 208. GM-CSF receptor (CD116) defective expression & function in 85% of IBD pts. n=52.
  • -Gastroenterology 2010; 139: 1816, 1844. Microbiome & affect on IBD vs mucosal homeostasis
  • -J Pediatr 2010; 157: 240. Microbiota in pediatric IBD -increased E coli and decreased F praunsitzil in IBD pts.
  • -J Pediatr 2009; 155: 781. early child care exposures lessens risk for asthma.
  • -IBD 2008; 14: 575.  Role of E coli in Crohn’s
  • -Lab Invest 2007; 87: 1042-1054. Role of E coli in Crohn’s
  • -Pediatrics 2007; 120: 354. Crohn’s less common after repeated exposure to farm animals in 1st year of life.

More practical information and links to other websites can be found at http://www.gicareforkids.com.