GI:: Inflammatory Bowel Disease

What pathology is seen in ulcerative colitis?

UC always involves the rectum you see hemorrhagic, granular mucosa and *pseudopolyps*. pseudopolyps are remnants of healthy tissue surrounded by superficial ulcers. there is a clear cutoff between healthy and diseased tissue.

What is inflammatory bowel disease?

Ulcerative colitis and Crohn's disease Recurring episodes of inflammation in the GI tract. IBD is caused by a bunch of stuff (we don't know): genetics, immune response, microbiome. Th1 and Th2 (depending on Crohn's vs. UC) is overactive, and Treg cells aren't doing enough to control immune activity.

What form of inflammatory bowel disease has granulomas?

*crohn's disease*

Chronic colitis histology 1

answer below: here you can see evidence of eosinophils and lymphocytes in the lamina propria you see crypt branching, and crypt size variation

Crohn's disease endoscopy 6

fistula (specific to crohn's disease. a great way to differentiate between crohn's and ulcerative colitis)

Active colitis histology 1

Answer below: In the middle of this picture you see some infiltration of the crypt lumen. This is a crypt abscess. Neutriphils have invaded and damaged the crypt lumen. There's also cryptitis (neutropihls in the crypt epithelial cells)

Cronh's vs. ulcerative colitis clinical findings comparison

Blood in stool: Crohn's rarely, UC almost always Mucus in stool: Crohn's rarely, UC almost always Systemic symptoms: Crohn's almost always, UC sometimes Pain: Crohn's almost always, UC sometimes Abdominal mass: Crohn's yes, UC rarely Perianal disease: Crohn's frequently, UC no. Extraintestinal disease: Crohn's fistulas and skin tags, UC gangrenosum and erythema nodosum Fistulas: Crohn's yes, UC no. Stricutres: Crohn's sometimes, UC no Small intestine obstruction: Crohn's often, UC no. Colonic obstruction: Crohn's sometimes, UC no.

Crohn's vs. Ulcerative colitis: complications

Both: Malabsorption/malnutrition, colorectal cancer (increased risk with pancolitis). Crohn's: Fistulas (eg, enterovesical fistulae, which can cause recurrent UTI and pneumaturia), phlegmon/abscess, strictures (causing obstruction), perianal disease. UC: Fulminant colitis, toxic megacolon, perforation.

Crohn's vs. Ulcerative colitis: extraintestinal manifestations

Both: Rash (pyoderma gangrenosum, erythema nodosum), eye inflammation (episcleritis, uveitis), oral ulcerations (aphthous stomatitis), arthritis (peripheral, spondylitis). Crohn's: Kidney stones (usually calcium oxalate), gallstones. May be (+) for anti-Saccharomyces cervisiae antibodies (ASCA). UC: primary sclerosing cholangitis. Associated with p-ANCA.

What are infectious causes of diarrhea?

C. diff, giardia, cryptosporidium, yersinia, aemba

What is chronic active colitis?

Chronic colitis (changes in crypt architecture) + present inflammation (neutrophils in crypts)

Crohn's disease summary

Clinical features: Chronic inflammatory disorder that can *involve any portion of the upper or lower GI tract*. Bloody diarrhea and abdominal pain with lower tract disease. Periods of exacerbation and remission. Increased risk of small bowel and colon cancer Pathogenesis: combination of genetic susceptibility, environmental factors, bacterial/floral antigens, and disturbances of mucosal immunity Gross features:* Segmental involvement with skip lesions. Cobblestone appearance, linear ulcers, fissures, fistulas, and fat wrapping* Microscopic features: Lymphoplasmacytic infiltrate expanding the lamina propria. Crypt abnormalities characteristic of chronic colitis. Neutrophils may be present. *Inflammation tends to be more patchy. Inflammation is transmural. Granulomas*

Ulcerative colitis summary

Clinical features: chronic inflammatory disorder of colon and rectum. symptoms = bloody diarrhea and abdominal pain. severity varies with time. increased risk of colon cancer Pathogenesis: combination of genetic susceptibility, environmental factors, bacterial/floral antigens, disturbances of mucosal immunity Gross features: UC always involves the rectum. inflammation spreads from the rectum into the colon in a continuous pattern. pseudopolyps = remnants of healthy tissue among superficial ulcers. Microscopic features: lymphoplasmacytic infiltrate expanding the lamina propria. Crypt abnormalities characteristic of chronic colitis. Neutrophils may be present. Inflammation is *limited to mucosa*

What are complications of Crohn disease?

Complications: stricture/obstruction (post-prandial pain/cramps, distention, vomiting, weight loss), fistulization (diarrhea, damage to skin, air/feces in urine) These complications are specific to Crohn's disease and not Ulcerative Colitis because Crohn's disease leads to inflammation of all layers of the intestinal walls, where ulcerative colitis is limited to the mucosa.

What is chronic colitis?

Consistent colon inflammation leading to changes in structure of the crypts of Lieberkuhn. Findings: crypt disarray, crypt dropout, and crypt branching. Inflammation in lamina propria

Crohn's mnemonic (first aid)

Crohn --> fat granny and old crone skipping down cobblestone road away from wreck creeping fat into intestines granuloma forming skipping lesions cobblestone appearance of intestine. rectal sparing

What GI disease is associated with enterocutaneous fistulas?

Crohn's disease

Crohn's vs. ulcerative colitis pathology comparison

Crohn's disease can happen in multiple discrete parts of the small and/or large intestines. Crohn's disease has *skip lesions* and is most common in the ileocolic junction. Crohn's disease has transmural inflammation, ulcerations, fissures, and fistulas. Ulcerative colitis always hits the rectum and can spread through the colon in a continuous fashion. Ulcerative colitis has superficial ulcers and pseudopolyps.

Where is Crohn disease found?

Crohn's disease is a form of inflammatory bowel disease. In Crohn's disease you can have inflammation involving *any part of the GI tract*. Inflammation can be *discontinuous/patchy* (opposed to ulcerative colitis). Inflammation extends through *all layers of bowel wall* (opposed to ulcerative colitis) Crohn's disease can impact *any part of the GI tract* but is most often *ileocolic* or in the *small intestine*

What is Crohn disease?

Crohn's disease is a form of inflammatory bowel disease. In Crohn's disease you can have inflammation involving *any part of the GI tract*. Inflammation can be *discontinuous/patchy* (opposed to ulcerative colitis). Inflammation extends through *all layers of bowel wall* (opposed to ulcerative colitis) Crohn's disease can impact *any part of the GI tract* but is most often *ileocolic* or in the *small intestine* Findings: skip lesions (space between regions of inflammation/damage, cobblestoning, inflammation through all layers of bowel wall --> strictures, fistulas. *fistulas* (as opposed to ulcerative colitis) Gross features: skip lesions, cobblestone, linear ulcers, fissures, fistulas, *fat wrapping* Symptoms: diarrhea, abdominal pain, failure to thrive, bowel obstruction, abscess, fistulas, weight loss, fever, fatigue. Complications: stricture/obstruction (post-prandial pain/cramps, distention, vomiting, weight loss), fistulization (diarrhea, damage to skin, air/feces in urine)

Crohn's disease (first aid)

Crohn's disease is an inflammatory bowel disease Location: any portion of the GI tract, usually the terminal ileum and colon. *skip lesions* and *rectal sparing* Gross morphology: Transmural inflammation --> *fistulas*. *cobblestone* mucosa, creeping *fat*, bowel wall thickening (string sign on barium swallow xray), *linear ulcers*, fissures Microscopic morphology: noncaseating granulomas and lymphoid aggregates. Th1 mediated. Intestinal manifestation: diarrhea, can be blood diarrhea. Extraintestinal manifestations: Rash (pyoderma gangrenosum, erythema nodosum), eye inflammation (episcleritis, uveitis) oral ulcerations, arthritis, ankylosing spondylitis. *kidney stones* (calcium oxalate), gallstones. (+) for ASCA. Complications: malabsoprtion, colorectal cancer, *fistulas* (enterovesical fistula) --> recurrent UTI and pneumaturia, abscess, strictures/obstruction, perianla disease. Treatment: Corticosteroids, azathioprine, ciprofloxacin, metronidazole, infliximab, adalimumab. Crohn --> fat infiltration, granulomas, cobblestone, skip lesions, rectal sparing, kidney stones, steroids.

Crohn's vs. Ulcerative colitis: location

Crohn's disease: Any portion of the GI tract, usually the terminal ileum and colon. Skip lesions, rectal sparing. Ulcerative colitis: Colitis = colon inflammation. Continuous colonic lesions, always with rectal involvement.

Crohn's vs. Ulcerative colitis: treatment

Crohn's: Corticosteroids, azathioprine, antibiotics (eg, ciprofloxacin, metronidazole), infliximab, adalimumab. UC: 5-aminosalicylic preparations (eg, mesalamine), 6-mercaptopurine, infliximab, colectomy.

Crohn's vs. Ulcerative colitis: intestinal manifestation

Crohn's: Diarrhea that may or may not be bloody UC: Bloody diarrhea

Crohn's vs. Ulcerative colitis: microscopic morphology

Crohn's: Noncaseating granulomas and lymphoid aggregates. Th1 mediated. Ulcerative colitis: Crypt abscesses and ulcers, bleeding, no granulomas. Th2 mediated.

Crohn's vs. Ulcerative colitis: gross morphology

Crohn's: Transmural inflammation --> fistulas. Cobblestone mucosa, creeping fat, bowel wall thickening ("string sign" on barium swallow x-ray), linear ulcers, fissures. UC: Mucosal and submucosal inflammation only. Friable mucosa with superficial and/or deep ulcerations. --> *pseudopolyps* as the only remaining healthy tissue is made to look like loads of sessile polyps. Loss of haustra --> "lead pipe" appearance on imaging.

What happens to crypts of leiberkuhn in chronic colitis?

Crypt disarray and dropout. crypts have atrophied, and some have branched. perpendicular section histology slide shows crypts of different depths, thicknesses, and not clearly ordered. cross section histology slide shows crypt size variation, no clear pattern in location and evidence of crypt dropout.

What are histology findings associated with chronic colitis?

Crypt disarray and dropout. crypts have atrophied, and some have branched. perpendicular section histology slide shows crypts of different depths, thicknesses, and not clearly ordered. cross section histology slide shows crypt size variation, no clear pattern in location and evidence of crypt dropout. lamina propria is filled with lymphocytes, plasma cells, and eosinophils

When do you get IBD?

Incidence peaks at 20 and 50 years old.

What histology findings are associated with ulcerative colitis?

Lymphoplasmacytic infiltrate expanding the lamina propria Crypt abnormalities characteristic of chronic colitis Neutrophils may be present Inflammation is limited to the mucosa

What causes colon inflammation?

Surgery Infection Ischemia Drug toxicties (NSAIDs) Diverticular disease Ulcerative colitis Crohn disease

What are symptoms of Crohn disease?

Symptoms: diarrhea, abdominal pain, failure to thrive, bowel obstruction, abscess, fistulas, weight loss, fever, fatigue. Complications: stricture/obstruction (post-prandial pain/cramps, distention, vomiting, weight loss), fistulization (diarrhea, damage to skin, air/feces in urine)

Ulcerative colitis mnemonic (first aid)

ULCCCERS Ulcers Large intestine Continuous lesions Colorectal carcinoma Crypt abscesses Extends proximally from rectum Red diarrhea Sclerosing cholangitis

What is ulcerative colitis?

Ulcerative colitis is a form of inflammatory bowel disease *limited to the colon*. Ulcerative colitis is a continuous inflammation of the colon, *always involving the rectum*. Ulcerative colitis spreads proximally up the colon from the rectum. Ulcerative colitis is an inflammation of the *mucosa* Symptoms: *progressive onset* of bloody diarrhea, mucoid stools, nocturnal diarrhea, tenesmus, urgency, abdominal pain, fever, weight loss, fatigue. Findings: erythema, edema, erosions, ulcers in the colon. ulcelrs are *superficial*. *pseudopolyps* (so much of the GI wall is inflamed and ulcerated that the remaining healthy tissue looks like a bunch of little pseudopolyps. There's a sharp cutoff between normal and diseased colon. In histology you see lymphocytic infiltration of lamina propria and crypt disarray. Inflammation is limited to mucosa. Complications: bleeding, malnutrition, failure to thrive, toxic megacolon --> sepsis, perforation, fulminant severe colitis, colon cancer

Ulcerative colitis (first aid)

Ulcerative colitis is an inflammatory bowel disease Location: Colon inflammation. Continuous colon lesions, 100% *rectal involvement* Gross morphology: mucosal and submucosal inflammation. Superficial ulcers, pseudopolyps (loads of ulcers make normal tissue look like polyps). Loss of haustra. Microscopic morphology: crypt abscesses and ulcers, bleeding, no granuloma. Th2 mediated. Intestinal manifestation: bloody diarrhea Extraintestinal manifestations: Rash (pyoderma gangrenosum, erythema nodosum), eye inflammation (episcleritis, uveitis) oral ulcerations, arthritis, ankylosing spondylitis, primary *slcerosing cholangitis*, p-ANCA Complications: malabsorption, colorectal cancer, fulminant colitis, toxic megacolon, perforation. Treatment: 5-aminosalicylate (mesalamine), 6-mercaptopurine, infliximab, colectomy. Ulcerative colitis causes ULCCCERS: Ulcers Large intestine Continuous lesion Colorectal carcinoma Crypt abscesses Extends proximally from rectum Red diarrhea Sclerosing cholangitis.

Crohn's disease vs. ulcerative colitis pathology summary

Ulcerative colitis: diffuse, continuous disease with 100% rectal involvement. Disease is worse towards rectum. No fissures, no transmural lymphoid aggregates, no ileal involvement, granulomas only if a cyst has ruptured. Crohn's disease: Skip lesions, variable rectal involvement, disease severity not related to location, fissures, fistulas, transmural lymphoid aggregates, upper GI tract involvement, epithelioid granulomas can pop up.

Active colitis histology 2

You can see here the colon has severe inflammation and ulceration

Compare and contrast active vs. chronic colitis

acute colitis: neutrophils are present. you see *cryptitis*, *crypt abscess*, and *ulceration* chronic colitis: *altered crypt architecture*: crypt dropout, crypt disarray, crypt branching. Increased inflammation in lamina propria.

Chronic colitis histology 2

answer below: here you see crypt disarray and dropout. you also see basal plasmacytosis (plasma cells in lamina propria)

What are complications of ulcerative colitis?

bleeding malnutrition growth failure *toxic megacolon* --> fulminant severe colitis, sepsis, perforation colon cancer

What are symptoms of ulcerative colitis?

bloody diarrhea mucoid stools nocturnal diarrhea urgency tenesmus abdominal pain fever weight loss fatigue

Crohn's disease endoscopy 4

cobblestoning

How do you diagnose ulerative colitis or crohn's disease?

colonoscopy capsule nedoscopy ct-enterography

ulcerative colitis histology 2

crypt abscesses = active chronic colitis

What are extra-intestinal symptoms of Crohn's disease?

enterocutaneous fistulas (crohn's disease) skin tags (crohn's disease)

What are extra-intestinal symptoms of ulcerative colitis?

erythema nodosum (usually ulcerative colitis) pyoderma gangernosum (usually ulcerative colitis)

Crohn's disease endoscopy 1

here's a deep linear ulcer

Crohn's disease histology 1

here's a granuloma, with lymphocytes. there're some inflammatory cells in the lamina propria over by the crypts of lieberkuhn in the upper section of the image.

Crohn's disease endoscopy 3

here's a tight stricture

Crohn's disease endoscopy 2

here's cobblestoning

Ulcerative colitis endoscopy

inflammation is continuous, not patchy. there's a sharp cutoff between what's healthy and diseased. findings: superficial ulceration, erythema, small punched out ulcers

What is active colitis?

inflammation of the colon with neutrophils present. Cryptitis: neutrophils in crypt epithelial cells Crypt abscess: neutrophils within crypt lumen Ulceration: inflammation disrupting mucosal surface

What happens to the lamina propria in chronic colitis?

lamina propria is filled with lymphocytes, plasma cells, and eosinophils

What are pathologic features of Crohn's disease?

linear ulcers fissures fistulas fat wrapping cobblestone appearance *skip lesions* = segmental involvement throughout GI tract.

What type of ulcers are seen in Crohn's disease?

linear ulcers, running *long* and *deep* between regions of healthy tissue (as opposed to ulcerative colitis with superficial ulcers). crohn's disease has ulcers that can penetrate through all layers of the bowel wall

Ulcerative colitis histology 3

pseudopolyp at otp of image surrounded by inflamed tissue crypt disarray (found in ulcerative colitis and crohn's)

What are pseudopolyps in ulcerative colitis?

pseudopolyps are islands of hyperplastic/regenerative mucosa surrounded by scarred/ulcerated mucosa. they're remnants of functional tissue.

Ulcerative colitis pseudopolyps image

pseudopolyps are remnants of healthy tissue surrounded by loads of superficial ulcers.

Crohn's disease endoscopy 5

serpiginous ulcers (wavy margins), cobblestoning.

What histology findings are associated with Crohn's disease?

transmural inflammation and thickening, granulomas, Lymphoplasmacytic infiltrate expanding the lamina propria Crypt abnormalities characteristic of chronic colitis Neutrophils may be present

ulcerative colitis histology 1

ulcer, inflammation, mucosal involvement, but no deep inflammation

What GI disease is associated with pyoderma gangernosum?

ulcerative colitis

what GI disease is associated with erythema nodosum?

ulcerative colitis

Where is ulcerative colitis found?

ulcerative colitis *always begins in the rectum* and progresses in a continuous pattern into the colon

Ulcerative colitis pathology image

you can see the clear cutoff between healthy and diseased colon, and you know it started in the rectum.

Crohn's disease endoscopy

you see strictures, linear ulcers, punched out ulcers, fistulas