Inflammatory Bowel Disease Exam 2 Flashcards
What are the etiologies of IBD?
- Infectious agents
- Genetics
- Immunologic
- Psychological
- Environmental
Etiologies of IBD: Infectious agents
- Microorganisms likely play a role in the initiation of inflammation
- Many organisms are suspected (measles virus, protozoa, mycobacteria, Listeria monocytogenes, Chlamydia trachomatis, Escherichia coli, toxin-producing bacteria)
- IBD patients have increased numbers of surface-adherent and intracellular bacteria
- IBD lesions occur more in areas of highest bacterial exposure
- Loss of tolerance against normal bacterial flora
- Bacterial peptides have chemotactic properties that cause inflammatory cells to arrive and release inflammatory mediators which cause tissue destruction
- Microbes elaborate superantigens which cause T-lymphocyte activation and inflammatory response
Etiologies of IBD: Genetics
- Genetic factors predispose patients to IBD
- First-degree relatives have a 20-fold increase in risk
- Genetic markers have been identified and associated with the development of disease
Etiologies of IBD: Immunologic
- Inappropriate reaction of the immune system (autoimmune and nonautoimmune)
- Immunologic mediators have been identified and play a role in the pathogenesis (lymphocytes, plasma cells, mast cells, macrophages, neutrophils)
- Contributes to systemic manifestations
- IBD is responsive to immunosuppressive drugs
Etiologies of IBD: Psychological
- Stress, emotional/physical trauma, etc. influence IBD but are not thought to be the actual cause
- Mental health changes correlate with remissions and exacerbations (especially UC)
Etiologies of IBD: Environmental
- Dietary habits of people in industrialized countries (where IBD is more common) may play a role
- Smoking is protective in UC but associated with twofold increase in frequency in CD
- NSAIDs – trigger occurrences and lead to flares via inhibition of protective prostaglandins
Severity categories of ulcerative colitis
- Mild
- Moderate
- Severe
- Fulminant
Severity categories of Crohn’s disease
- Mild / moderate
- Moderate / severe
- Severe / fulminant
Ulcerative colitis: Mild
< 4 stools/day +/- blood, with no systemic complications and normal ESR
Ulcerative colitis: Moderate
> 4 stools/day with blood, but with minimal systemic complications
Ulcerative colitis: Severe
> 6 stools/day with blood, with evidence of systemic complications as indicated by fever, tachycardia, anemia, or ESR > 30
Ulcerative colitis: Fulminant
> 10 stools/day with continuous bleeding, systemic toxicity, abdominal tenderness, requirement for transfusions and colonic dilation
Crohn’s disease: Mild / moderate
ambulatory patients with no evidence of dehydration, systemic toxicity, weight loss, abdominal tenderness, mass, or obstruction
Crohn’s disease: Moderate / severe
patients that fail to respond to treatment for mild/moderate disease, those with fever, weight loss, abdominal pain, tenderness, vomiting, obstruction, or anemia
Crohn’s disease: Severe / fulminant
presence of persistent symptoms, evidence of systemic toxicity despite outpatient corticosteroids or biologic treatment, presence of cachexia, rebound tenderness, intestinal obstruction, or abscess