Inflammatory Bowel Disease Flashcards
2 classes of inflammatory bowel disease
- ulcerative colitis
- Crohn disease
inflammatory bowel diseases
*chronic inflammatory disorders involving the GI tract, thought to be related to dysregulation of the gut immune system
*exact cause of these diseases is unknown
IBD epidemiology
*common in North America & Europe
*UC and Crohn’s disease have equal incidence
*age of onset 15-40
*equally affects males and females
*more common in whites
ulcerative colitis - key characteristics
*inflammation limited to mucosa & submucosa
*involves the colon (COLITIS) only
*ALWAYS involves the rectum and extends proximally in continuous fashion to a variable degree
Crohn’s disease - key characteristics
*inflammation involves the entire bowel wall (transmural)
*can involve GI tract from mouth to anus
*typically spares the rectum and involves the GI in a discontinuous fashion (skip lesions)
ulcerative colitis - clinical presentation
*bloody diarrhea (usually painful)
Crohn disease - clinical presentation
*RLQ pain and diarrhea (may or may not be bloody)
ulcerative colitis - characteristic histology
*crypt abscesses/ulcers
*bleeding
*no granulomas
Crohn disease - characteristic histology
*noncaseating granulomas
*lymphoid aggregates
IBD diagnosis
*history: chronic diarrhea, rectal bleeding, abdominal pain, tenesmus (rectal pressure and pain, urge to defecate)
*PE: focal tenderness
*labs: stool studies to evaluate for infectious etiologies; FECAL CALPROTECTIN; ESR, CRP, CBC, IBD serologies
*radiology
*colonoscopy
auto-antibody for ulcerative colitis
p-ANCA
auto-antibody for Crohn’s dsease
ASCA
extraintestinal manifestations of IBD
*erythema nodosum
*PYODERMA GANGRENOSUM
*oral aphthous ulcers
*episcleritis
*uveitis
*peripheral arthritis
*axial arthritis (sacroileitis, ankylosing spondylitis)
*primary sclerosing cholangitis
gut immunology - key players
*luminal bacteria
*epithelial cells (tight junctions, goblet cells, Paneth cells, M cells)
*toll-like receptors
*NOD proteins
*dendritic cells
*Peyer’s patches, lymph nodes
*CD4+ T cells
lifestyle modifications for IBD
*cigarette smoking: exacerbates Crohn’s disease but may decrease ulcerative colitis activity (make UC better)
*use of NSAIDs may exacerbate disease activity
5-aminosalicylic acid (5-ASA) for IBD
*topical anti-inflammatory effects, exact mechanism unknown
*may decrease production and function of pro-inflammatory cytokines, prostaglandins, and leukotrienes
*may decrease leukocyte adhesion
*ADEs: safe class of meds; nausea & headaches
IBD therapies
*5-ASA (sulfasalazine)
*glucocorticoids (ex. prednisone)
*budesonide
*immunomodulators (thiopurines, methotrexate)
*anti-tumor necrosis factor
*anti-integrin
*cytokine inhibitor
*JAK inhibitor
anti-tumor necrosis factor for IBD
*ex. infliximab
*effective in decreasing inflammation and closing fistula
*ADEs: reactivated infection with TB, HBV; possible increased incidence of lymphoma
anti-integrins for IBD
*ex. vedolizumab
*inhibits leukocyte adhesion and migration into intestinal submucosa
*ADEs: reactivated infection with TB, HBV; lymphoma; PML
cytokine inhibitors for IBD
*ex. ustekinumab
*blocks IL-12 and IL-23 by inhibiting the p40 receptors on T cells
*ADEs: reactivated infection with TB, HBV? RPLS (reversible posterior leukoencephalopathy syndrome)
treatment of ulcerative colitis
*step-up approach:
1. 5-ASA or sulfasalazine FIRST
2. prednisone or budesonide
3. immunomodulators
4. biologic agents
5. surgery (last step of tx, but it is curative)
treatment of Crohn’s disease
*top-down approach: (start with 1 and 2)
1. biologic agents
2. immunomodulators
3. prednisone or budesonide
indications for surgical therapy of Crohn’s disease
*medically refractory disease
*strictures
*fistulae
*abscess drainage
we try to keep surgery to a minimum in Crohn’s disease
indications for surgical therapy of ulcerative colitis
*medically refractory disease
*toxic megacolon
*dysplasia/cancer
note - consider total proctocolectomy
*surgery is curative
microscopic colitis
*a chronic inflammatory condition that is a cause of chronic, non-bloody, watery diarrhea, typically in middle-aged females
*a histologic diagnosis: colon appears normal at colonoscopy
*2 subtypes:
-lymphocytic colitis: increased intraepithelial lymphocytes
-collagenous colitis: subepithelial collagen band
*possible associations: celiac disease, NSAID use, smoking
*dx: histologic
*treatment: loperamide or budesonide
diversion colitis
*a chronic inflammatory condition that occurs in segments of the colon that have been excluded from the fecal stream
*typically asymptomatic, incidentally discovered during endoscopic examination of the excluded segment of colon
*colonocytes partially depend on the fecal stream for nutrients; diversion colitis is thought to be on the basis of a deficiency of short-chain fatty acids
*dx: colonoscopy & biopsy
*tx: surgical re-establishment of continuity of the bowel
*short-chain fatty acid enemas
