INFLAMMATORY BOWEL DISEASE

CLINICAL PRESENTATION:  Inflammatory bowel disease is distinguished from infectious entities by exclusion and by chronicity (months; not days or weeks). Patients often experience recurrent episodes of mucopurulent, bloody diarrhea characterized by lack of positive cultures for known microbial pathogens and failure to respond to antibiotics alone. Antibiotics:  Microbial pathogens

Because inflammatory bowel disease is characterized by exacerbations and remissions, favorable responses to therapy may be difficult to distinguish from spontaneous remissions occurring as part of the natural history of the disease.

ETIOLOGY:  Triggers for the development of IBD remain elusive. However, epidemiologic studies suggest that smoking and gastrointestinal infections are possible contributory factors. There are two forms of chronic inflammatory bowel disease: Crohn’s disease, which is transmural and granulomatous in character, occurring anywhere along the GI tract; and ulcerative colitis, which is superficial and limited to the colonic mucosa.  Ulcerative colitis

The exact causes of inflammatory bowel disease are unknown despite progress in understanding its pathogenesis.

PATHOLOGY & PATHOGENESIS:  Genetic risk and environmental factors are recognized as two key elements in the pathogenesis of inflammatory bowel disease. An explosion of newly recognized susceptibility genes for both Crohn disease and ulcerative colitis have been discovered through genome-wide associations. These studies evaluated thousands of single nucleotide polymorphisms (SNPs) in thousands of patients with inflammatory bowel disease and compared them with SNPs from thousands of people without the disease (controls). These studies found abnormalities in several categories of susceptibility genes in patients with inflammatory bowel disease. These included modulators of immune function, autophagy, and epithelial function that participate in the interaction of host and microorganism. Importantly, the relative risk of most of these susceptibility genes is low (most have a 20–30% increase in relative risk of developing disease).  Therefore, most people who harbor risk alleles for inflammatory bowel disease do not develop disease.  Genetic factors are clearly not the sole contributor to inflammatory bowel disease.  Many environmental factors have been found to contribute to the development of Crohn’s disease, including pathogenic microorganisms (bacteria and viruses), the repertoire of indigenous intestinal microbes (the microbiota), dietary factors, smoking, defective immune responses, and psychosocial factors.

RELATED;

1.  CONSTIPATION

2.  ULCERATIVE COLITIS

3.  MEDICAL CONDITIONS

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