result from an abnormal local immune response against the normal flora of the gut, and probably against some self antigens, in genetically susceptible individuals
Crohn disease may affect from esophagus to anus but most often involves the ileum; about half of cases exhibit noncaseating granulomatous
Ulcerative colitis is a nongranulomatous disease limited to the colon
First-degree relatives are 3 to 20 times more likely
Pathogenesis include imbalance between 2 factors
(1) factors that activate the host immune system, such as luminal microbes, dietary antigens, and endogenous inflammatory stimuli; and
(2) host defenses that down-regulate inflammation and maintain the integrity of the mucosa
Genetic Predisposition:
Ulcerative colitis has been associated with HLA-DRB1, whereas
HLA-DR7 and DQ4 alleles are associated with approximately 30% of Crohn disease
Immunologic Factors
predominant class of T-cell response.The inflammatory cytokine TNF may play an important role and TNF antagonist are used in the treatment
neutrophils initially and mononuclear cells later in the course
perinuclear antineutrophil cytoplasmic antibodies, which are present in about 75% of persons with ulcerative colitis
End results:
(1) impaired integrity of the mucosal epithelial barrier, and
(2) loss of surface epithelial cell absorptive function
Note the similitudes between case finding and screening: both try to hazard delineate the populace utilizing a straightforward and modest method, and expect that better results can be accomplished through distinguishing the beginning phases of disease and offering brief treatment. alzheimer's disease wiki
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