3/20 IBD - Corbett Flashcards
complex pathogenesis of IBD
Crohn’s vs UC immune responses
-
genetics
- bacterial sensing and autophagy gene polymorphisms
-
microbiome
- microbial dysbiosis in IBD pts
- epithelial defects
-
mucosal immune response
- Th1 cell activation
- proinfl cytokine response (TNF, IL10, IL10r mutations)
Crohn’s linked to Th1 response
UC linked to Th2 response
Crohn disease
- peak incidence: 15-25, second peak 60s
- higher risk in smokers
- genetic predisposition (first deg relative = 10-15x risk), Ashkenazi Jews
MAJOR FEATURES
- chronic transmural infl disease
-
ANY PART of GI tract can be affected (mouth to anus)
- most common: terminal ileum/cecum
- macroscopic ft
- skip lesions : sharply delineated areas of disease, “cobblestone” appearance
- linear fissures/deep ulcers : deep extension → fistulas/performations
- transmural involvement : thickened bowel w hypertrophy of muscularis propria
- “creeping fat”
-
microscopic ft
- crypt abscesses
- noncaseating granulomas (not in every case, but pathognomonic)
CLINICAL PRESENTATION
- “small int” diarrhea (voluminous, less freq)
- RLQ abd pain +/- mass
- malabs, wt loss, n/v, fever, malaise
- extraintestinal manifestations
Crohn disease
ileocolitis
jejunoileitis
colonic/perianal disease
ileocolitis
- infl with acute RLQ pain/diarrhea
- obstruction via fibrosis/stricture
- fistula formation
jejunoileitis
- malabs → steatorrhea, nutritional def
- hyperoxaluria
colonic/perianal disease
- crampy abd pain, diarrhea, hematochezia
- 30% perianal disease: anorectal fistula, perirectal abscesses
Crohn disease complications
fistula formation
small bowel obstruction
B12 malabsoption
fat malabs (bile salt issues)
malignancy
extraintestinal manifestations
(30% of patients)
- most common: arthritis
- nondestructive periph arthritis of large joints (both CD and UC
- ankylosing spondilitis (CD > UC)
- skin manifestations
- erythema nodosum: immune complex deposition in fat venules with vasculitis, tender subcut nodules
- pyoderma gangrenosum: neutrophil-predominant skin infiltrates, infl pustule expanding to ulcer
- eye
- episcleritis: infl of episcleris (acute onset redness/burning/itching)
- uveitis: infl of choroid and retina (floaters?)
- liver (uncommon)
-
primary sclerosing cholangitis: infl, fibrosis, stricture of med/lg ducts in intra/extrahepatic biliary tree
- 90% of patients with PSC have UC
- assoc with HLAB2/DR3
- FATIGUE
- incr risk of cholangiocarcinoma
-
primary sclerosing cholangitis: infl, fibrosis, stricture of med/lg ducts in intra/extrahepatic biliary tree
nephrolitiasis in Crohn’s due to incr oxalate abs in terminal ileum
ulcerative colitis
- peak incidence: 20-30s, second peak over 60
- risk: smoking (maybe)
- genetic predisposition (first deg relative = 10-15x risk), Ashkenazi Jews
MAJOR FEATURES
- chronic mucosal infl disease
-
rectum first → extends proximally up to some extent of colon
- rectosigmoid (45)
- pancolitis (20)
- macroscopic ft
- continuous lesions : NOT skip; present w “psudopolyps”
- might see: dysplasia, dilatation/toxic megacolon (due to damage to muscularis)
- lead pipe on image
-
microscopic ft
- crypt abscesses
- inflammation confined to mucosa/superficial submucosa
- no granulomas
CLINICAL PRESENTATION
- “large int” diarrhea (frequent, small, blood/mucus)
- rectal bleeding
- tenesmus
- crampy abd pain
- systemic sx: fever, fatigue, wt loss
UC complications
acute comp
- acute bleeding
- fulminant colitis
- toxic megacolon: muscular layer loses competency → dilatation
- fever, low BP, incr HR, abd distension/tenderness
- perforation
chronic comp
- strictures can occur (but uncommon)
- dysplasia and colorectal cancer
- extent of colitis and duration of disease
- presence of sclerosing cholangitis
drug list for IBD
1, 3, 4, 5 used for both
ANTIBIOTICS used for Crohn’s disease (not for UC bc of risk for C. diff colitis)
METHOTREXATE only used in Crohns
and biologics
- antiTNF
- infliximab
- adalimumab
- anti-integrins
- natalizumab
CD vs UC
