inflammatory bowel disease (IBD)

see also:

• RIF pain in the ED
• arthritis - clinical patterns
• general surgery
• gastroenterology
• Crohn's disease
• ulcerative colitis

• inflammatory bowel disease is the generic term for a range of “autoinflammatory” diseases including:
  • Crohn's disease
  • ulcerative colitis
  • microscopic colitis:
    • more common in older adults (50-70 years old) and women
    • normal colonoscopy appearance
    • may have higher rates of autoimmune disorders like celiac disease, thyroid disorders, and rheumatoid arthritis
    • Rx options include dietary changes, anti-diarrheal medications, and anti-inflammatory drugs like budesonide. Most people respond well to treatment.
    • types:
      • lymphocytic colitis
      • collagenous colitis

• mechanisms are not well understood as yet
• Hepworth et al ¹⁾ propose the following mechanism:
  • a subset of innate lymphoid cells called ILC3 cells which normally reside in the lamina propria of the bowel and in mesenteric lymph nodes, selectively kill CD4 T cell lymphocytes that are capable of responding to bacterial antigen originating from the gut.
  • normally these ILC3 cells prevent the immune system from mounting an inflammatory response to these non-pathogenic bacteria gut flora in a similar way as thymic medullary epithelial cells or dendritic cells of the thymus kill off specific CD4 T cells to reduce the risk of auto-immune diseases
  • biopsies of children with Crohn's disease reveal a deficiency in the expression of ILC3-instrinsic MHC class II suggesting this could be a key component of the pathogenesis

• corticosteroids
• sulphasalazine (salazopyrine)
• TNF antagonists
• monoclonal antibodies to integrin:
  • iv vedolizumab every 8wks (introduced in Australia in 2015)

• neurostimulation of the splenic nerve
  • 2025 study of a novel splenic nerve wireless stimulator (SpNWS) built from stretchable and highly-conductive hydrogel for chronic electroceutical immunomodulation therapy appears to show benefit in IBD in rat models and significantly reduced colitis severity and restored intestinal immune balance by suppressing TH1/TH17 responses and enhancing TH2/Treg activity²⁾