Inflammatory Bowel Disease

Question 1

2 classes of inflammatory bowel disease

Answer 1

1. ulcerative colitis
2. Crohn disease

Question 2

inflammatory bowel diseases

Answer 2

*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

Question 3

IBD epidemiology

Answer 3

*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

Question 4

ulcerative colitis - key characteristics

Answer 4

*inflammation limited to mucosa & submucosa
*involves the colon only
*always involves the rectum and extends proximally in continuous fashion to a variable degree

Question 5

Crohn’s disease - key characteristics

Answer 5

*inflammation can involve 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)

Question 6

ulcerative colitis - clinical presentation

Answer 6

*bloody diarrhea (usually painful)

Question 7

Crohn disease - clinical presentation

Answer 7

*RLQ pain and diarrhea (may or may not be bloody)

Question 8

ulcerative colitis - characteristic histology

Answer 8

*crypt abscesses/ulcers
*bleeding
*no granulomas

Question 9

Crohn disease - characteristic histology

Answer 9

*noncaseating granulomas
*lymphoid aggregates

Question 10

IBD diagnosis

Answer 10

*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

Question 11

auto-antibody for ulcerative colitis

Answer 11

p-ANCA

Question 12

auto-antibody for Crohn’s dsease

Answer 12

ASCA

Question 13

extraintestinal manifestations of IBD

Answer 13

*erythema nodosum
*PYODERMA GANGRENOSUM
*oral aphthous ulcers
*episcleritis
*uveitis
*peripheral arthritis
*axial arthritis (sacroileitis, ankylosing spondylitis)
*primary sclerosing cholangitis

Question 14

gut immunology - key players

Answer 14

*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

Question 15

lifestyle modifications for IBD

Answer 15

*cigarette smoking: exacerbates Crohn’s disease but may decrease ulcerative colitis activity (make UC better)
*use of NSAIDs may exacerbate disease activity

Question 16

5-aminosalicylic acid (5-ASA) for IBD

Answer 16

*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

Question 17

IBD therapies

Answer 17

*5-ASA (sulfasalazine)
*glucocorticoids (ex. prednisone)
*budesonide
*immunomodulators (thiopurines, methotrexate)
*anti-tumor necrosis factor
*anti-integrin
*cytokine inhibitor
*JAK inhibitor

Question 18

anti-tumor necrosis factor for IBD

Answer 18

*ex. infliximab
*effective in decreasing inflammation and closing fistula
*ADEs: reactivated infection with TB, HBV; possible increased incidence of lymphoma

Question 19

anti-integrins for IBD

Answer 19

*ex. vedolizumab
*inhibits leukocyte adhesion and migration into intestinal submucosa
*ADEs: reactivated infection with TB, HBV; lymphoma; PML

Question 20

cytokine inhibitors for IBD

Answer 20

*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)

Question 21

treatment of ulcerative colitis

Answer 21

*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)

Question 22

treatment of Crohn’s disease

Answer 22

*top-down approach: (start with 1 and 2)
1. biologic agents
2. immunomodulators
3. prednisone or budesonide

Question 23

indications for surgical therapy of Crohn’s disease

Answer 23

*medically refractory disease
*strictures
*fistulae
*abscess drainage

we try to keep surgery to a minimum in Crohn’s disease

Question 24

indications for surgical therapy of ulcerative colitis

Answer 24

*medically refractory disease
*toxic megacolon
*dysplasia/cancer

note - consider total proctocolectomy
*surgery is curative

Question 25

microscopic colitis

Answer 25

*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

Question 26

diversion colitis

Answer 26

*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