Colon

Question 1

What is pseudomembranous colitis?

Answer 1

clinicopathologic diagnosis associated with pseudomembrane formation from necrotic epithelial cells, acute inflammatory cells, and fibrinous material

caused by: C. difficile colitis, ischemic colitis, diversion colitis, idiopathic IBD

Question 2

What is the mechanism of pseudomembranous colitis?

Answer 2

enterotoxin A –> cell damage, inflammation

Cytotoxin B –> cell death

third toxin –> stimulates colonic motor activity

Question 3

What are the symptoms of pseudomembranous colitis?

Answer 3

diarrhea after taking antibiotics

can be mild/self-limited or chronic

can present as toxic megacolon

Question 4

What is the gross pathology of pseudomembranous colitis?

Answer 4

discrete, raised, indurated, creamy yellow plaques that attach to GI tissues

affects large bowel almost exclusively

Question 5

What are the microscopic findings of pseudomembranous colitis?

Answer 5

well-demarcated disrupted crypts with an overlying pseudomembrane

Question 6

What is the distribution of ulcerative colitis?

Answer 6

begins in rectum and spreads proximally to the whole colon

Question 7

What are the symptoms of ulcerative colitis?

Answer 7

large volumes of watery diarrhea and passage of blood per rectum

Question 8

What are the macroscopic features of ulcerative colitis?

Answer 8

shortening of colon

oozing of blood, friable mucous membranes

full thickness ulceration that is patchy

Question 9

What are the microscopic features of ulcerative colitis?

Answer 9

crypt abscess formation with goblet cell depletion

mucosal inflammation that does not extend beyond the submucosal layer

Question 10

What are the complications of ulcerative colitis?

Answer 10

toxic megacolon, perforation, hemorrhage, cancer

systemic: uveitis, arthritis, sclerosing cholangitis, pyoderma gangrenosum

Question 11

What are the major types of neoplastic polyps?

Answer 11

tubular adenoma

villous adenoma (worse prognosis)

adenoma-carcinoma sequence

Question 12

What is the molecular pathogenesis of familail adenomatous polyposis?

Answer 12

autosomal dominant mutation in APC gene (tumor suppressor)

Question 13

What is the natural history of familial adenomatous polyposis?

Answer 13

colon with 100-1000s of polyps that eventually develop into colorectal adenomas within 2-3 decades of life

Question 14

What dietary factors contribute to adenocarcinoma of colon and rectum?

Answer 14

high animal fat diet

low fiber diet

nitroso compounds from grilled meat and fish

Question 15

What are the histological findings of adenocarcinoma of colon and rectum?

Answer 15

adenocarcinomas with some mucin

Question 16

What lesions are precancerous for colon/rectal adenocarcinoma?

Answer 16

familial polyposis, large adenomas, ulcerative colitis, Chron’s disease

Question 17

What is this?

Answer 17

normal histology of the colon

Question 18

What is this?

Answer 18

ulcerative colitis

cryptitis and crypt abscesses

Question 19

What is the difference between the distribution of Crohn’s disease and ulcerative colitis?

Answer 19

Crohn’s disease: transmural, discontinuous inflammation

ulcerative colitis: continuous ascending inflammation from rectum

Question 20

What are the histological differences betwen ulcerative colitis and Crohn’s disease?

Answer 20

UC: crypt abscess with mucosal-restricted inflammation

CD: granulomas with transmural inflammation

Question 21

Which IBD is associated with primary sclerosing cholangitis?

Answer 21

ulcerative colitis

Question 22

What is this?

Answer 22

hyperplastic polyp of colon

star-shapped/serration pattern

Question 23

What genetic mutation is associated with juvenile polyposis?

Answer 23

SMAD4 mutation

Question 24

What type of diverticuli occur in the colon? How do they arise?

Answer 24

pseudo-diverticula –> do not include all layers of the colon

herniation of mucosa through the muscularis propria at weak points in the colonic wall (where vasa recta penetrates) caused by abnormal motility

Question 25

What is diverticulitis?

Answer 25

inflammation of a diverticulum due to obstruction of the opening, often from a ball of stool

Question 26

What is the natural history of diverticulitis?

Answer 26

mostly uncomplicated and will resolve with rest +/- antibiotics may require surgery if abscess, macro perforation, strictures, fistulas form 1/3 recurrent episode after first attack, 1/3 of those will have a third epsode

Question 27

What is diverticular bleeding?

Answer 27

painless bleeding from rectum due to segmental weakness of the vasa recta

Question 28

What are the risk factors for diverticular bleeding?

Answer 28

hypertension, atherosclerosis, NSAID use

Question 29

What is symptomatic colitis with diverticula (SCAD)?

Answer 29

inflammation of interdiverticular mucosa without involvement of diverticular orifices

Question 30

What is symptomatic uncomplicated diverticular disease (SUDD)?

Answer 30

persistent pain attributed to diverticula in the absence of overt colitis or diverticulitis, likely due to visceral hypersensitivity

Question 31

What are the two watershed regions of the colon?

Answer 31

splenic flexure (Griffith's point) rectosigmoid junction (Sudeck's point)

Question 32

What are the three mechanisms of injury in ischemic colitis?

Answer 32

non-occlusive ischemia embolic or thrombolic arterial occlusion mesenteric venous occlusion

Question 33

What is the cause of non-occlusive ischemic colitis? What is the damage pattern?

Answer 33

cause: cardiac failure, shock, dehydration, vasoconstrictive drugs chronic disease process, leads to damage limited to muscularis mucosa (not transmural)

Question 34

What are causes of embolic/thrombotic arterial occlusive ischemic colitis? What is the pattern of damage?

Answer 34

causes: emboli, aortic instrumentation, vasculitis, atherosclerosis, aortic aneurysms, hypercoaguable states transmural infarction

Question 35

What is the clinical presentation of ischemic colitis?

Answer 35

sudden onset cramping and tenderness over affected bowel with mild to moderate rectal bleeding

Question 36

What is this?

Answer 36

lymphocytic colitis ## Footnote *intraepithelial lymphocyte infiltration in colon, \> 20 per high powered field*

Question 37

What is this?

Answer 37

collagenous colitis ## Footnote *colonic subepithelial collagen band*

Question 38

What are the two major types of microscopic colitis?

Answer 38

lymphocytic colitis collagenous colitis

Question 39

What are major causes/associations with microscopic colitis?

Answer 39

middle-aged or older women autoimmune diseases triggers: NSAIDs, PPIs, ranitidine, sertraline, smoking

Question 40

What is the clinical presentation of microscopic colitis?

Answer 40

chronic watery diarrhea, normal labs, normal colonoscopy (need biopsy)

Question 41

How is microscopic colitis diagnosed?

Answer 41

requires biopsy and histologic diagnosis

Question 42

Why are diverticuli most common in the sigmoid colon?

Answer 42

it has the smallest diameter and is thus under the highest pressure, predisposing it to diverticula formation

Question 43

Which of the following should be recommended to a patient after their first episode of diverticulitis? a) avoidance of nuts and seeds b) surgery to prevent recurrence c) colonoscopy in 2-4 weeks d) CT scan in 4 weeks to ensure resolution of inflammation e) high fiber diet

Answer 43

c) colonoscopy in 2-4 weeks

Question 44

A 65 yo male with a history of coronary artery disease presents with sudden onset abdominal pain, urgency, and diarrhea following a syncopal episode at home. He subsequently develops bloody diarrhea and is admitted to the hospital. He has never had a colonoscopy. Which of the following is the most likely cause of his bleeding: a) diverticular bleeding b) microscopic colitis c) ischemic colitis d) colon cancer e) hemorrhoids

Answer 44

a) diverticular bleeding

Question 45

Which of the following is true regarding microscopic colitis: a) it is predominantly seen in young, male patients b) abdominal pain is a common symptom c) ranitidine is implicated as a possible trigger d) presence of \> 10 intraepithelial lymphocytes per high power field is diagnostic of lymphocytic colitis

Answer 45

c) ranitidine is implicated as a possible trigger ## Footnote * A is not true bc it is more common in older women* * B is not true because it presents with chronic, watery diarrhea* * D is not true because it requires \> 20 for diagnosis*

Question 46

Which IBD does this describe: colon involvement only

Answer 46

ulcerative colitis ## Footnote *Crohn's disease involves any part of GI tract*

Question 47

Which IBD does this describe: focal, skip lesions

Answer 47

Crohn's disease ## Footnote *Ulcerative colitis is diffuse, contiguous*

Question 48

Which IBD does this describe: transmural involvement with granulomas

Answer 48

Crohn's disease ## Footnote *ulcerative colitis has only superficial inflammation*

Question 49

What are the clinical GI symptoms of IBD?

Answer 49

depends on which part of GI tract is involved diarrhea, blood in stool, abdominal pain/cramping, rectal pain, weight loss, nausea/vomiting, failure to thrive in infants

Question 50

What are the extraintestinal symptoms of IBD?

Answer 50

joint/bone involvement: ankylosing spondylitis, metabolic bone disease skin: pyoderma gangrenosum, erythema nodosum, apthous ulcers ocular: episcleritis, uveitis hepatobiliary: primary sclerosing cholangitis (ulcerative colitis), cholelithiasis, autoimmune hepatitis renal: kidney stones

Question 51

What is the treatment for IBDs?

Answer 51

5-ASA antibiotics steroids immunomodulators anti-TNF and anti-adhesion molecule biologics surgery

Question 52

A 20 yo male who quit smoking 2 months ago presents with intermittent bright red blood per rectum. He has no abdominal pain, constipation, or diarrhea. He does note some fecal urgency and mucous discharge. His symptoms have been ongoing for 6 months. Physical exam unremarkable, labs unremarkable except slight anemia (low Hgb). What should be done next for evaluation? a) endoscopic evaluation b) abdominal CT scan c) stool culture d) trial of OTC hemorrhoid medication

Answer 52

a) endoscopic evaluation

Question 53

A 20 yo female with Crohn's disease presents with severe right flank pain and is found to have kidney stones. She most likely has Crohn's disease of the: a) colon b) esophagus c) stomach d) ileum

Answer 53

d) ileum

Question 54

Which of the following **are** extraintestinal manifestations of IBD: a) episcleritis b) cervical lymphadenopathy c) oral apthous ulcers d) erythema nodosum e) sacroileitis f) pyoderma gangrenosum g) nephrolithiasis h) osteoarthritis i) primary sclerosing cholangitis j) gallstones

Answer 54

a) episcleritis c) oral apthous ulcers d) erythema nodosum e) sacroileitis f) pyoderma gangrenosum g) nephrolithiasis i) primary sclerosing cholangitis j) gallstones ***B and H are not associated with IBD***

Question 55

The diagnosis of IBD is made by: a) histology b) endoscopy c) radiology d) clinical history e) all of the above

Answer 55

e) all of the above

Question 56

An 18 yo female presents with abdominal pain and bloody diarrhea after returning from a trip to mexico. She was empirically givencirpofloxacin by her PCP without benefit. It has now been 6 weeks after her return and she still has 3-4 bowel movements daily with blood and slight abdominal cramping with bowel movements. She has a colonoscopy and there is diffuse, continuous inflammation, granular appearing mucosa starting in rectum up to splenic flexure. The colon proximal to this and the ileum appears normal. What is the most likely diagnosis? a) Crohn's disease b) ulcerative colitis c) infectious colitis d) irritable bowel syndrome

Answer 56

b) ulcerative colitis

Question 57

What are risk factors for colorectal cancer?

Answer 57

high fiber consumption, obesity possibly also: diabetes, cholecystectomy, eating red meats, smoking, alcohol, radiation

Question 58

What are protective factors for colorectal cancer?

Answer 58

high fiber consumption, physical activity, low BMI, NSAIDs possibly also: calcium, magnesium, HRT, statins

Question 59

What is the relationship of genetic factors in colorectal cancer?

Answer 59

most are sporadic not familial, but in familial cases and syndromes there is a large risk

Question 60

What types of polyps increase risk of colorectal cancer?

Answer 60

large, adenomatous polyps multiple polyps polyps with villous features

Question 61

What is the relationship between IBD and colorectal cancer?

Answer 61

ulcerative colitis increases risk of colorectal cancer

Question 62

What is the adenoma-carcinoma sequence?

Answer 62

APC mutation for FAP or mismatch repair mutations for Lynch syndrome (initial mutation) K-Ras mutations and DCC mutations contribute to carcinogenesis

Question 63

What are the symptoms of colorectal cancer?

Answer 63

abdominal pain/rectal pain, change in bowel movement patterns, hematochezia, anemia, weight loss/fatigue, symptoms of metastatic disease (liver, lung, lymph nodes, peritoneum)

Question 64

What is the best screening method for colorectal cancer?

Answer 64

colonoscopy

Question 65

What is the TNM system of cancer staging?

Answer 65

T = depth of tumor invasion N = lymph node involvement M = metastases

Question 66

How is colorectal cancer treated?

Answer 66

mostly with surgery if it is possible to remove the whole lesion can also involve chemotherapy, radiation, andpalliation of symptoms

Question 67

What are all of the screening methods for colorectal cancer?

Answer 67

fecal occult blood test --\> low cost, easy to use, but lower sensitivity Fecal DNA Combo fecal blood and DNA Flexible sigmoidoscopy colonoscopy CT colonography capsule colonoscopy

Question 68

When should patients be screened for colorectal cancer?

Answer 68

without family history or history of polyps/cancer: start at 45 or 50 and screen every 10 years until age 75 with family history in person under 60: start 10 years before they were diagnosed (or at age 40) and screen every 5 years with family history in person 60+: start at 40 and, if negative, continue with general 10 year screening pattern with history of IBD: colonoscopy every 1-2 years

Question 69

How should patients with FAP be screened for colorectal cancer?

Answer 69

genetic testing annual endoscopic screening colectomy for patients with the genetic mutation + polyps

Question 70

How should patients with Lynch syndrome be screened for colorectal cancer?

Answer 70

genetic counseling colonoscopy starting at age 20-25 every 1-2 years

Question 71

With respect to the epidemiology and risk factors, which of the following is correct? a) the incidence of colorectal cancer is generally lower in more developed countries b) in the US, colorectal cancer is the most common gastrointestinal cancer c) a diet high in fiber has been associated with a higher risk of colorectal cancer d) obesity has been associated with lower risk of colorectal cancer

Answer 71

b) in the US, colorectal cancer is the most common gastrointestinal cancer

Question 72

A 55 yo man had a screening colonoscopy, revealing 3 adenomatous polyps which were completely removed. With respect to pathogenesis, familial risk, and need for future follow up, which is the most appropriate recommendation: a) no further evaluation required in the future, since the polyps were all removed b) this patient's 2 brothers, ages 51 and 53, are not at increased risk and do not need to be screened for colorectal cancer c) he should have genetic testing performed now, as most colorectal polyps are found in individuals with genetic syndromes d) he should undergo surveillance colonoscopy at the interval recommended by his physician d) he should undergo surveillance colonoscopy at the interval recommended by his physician

Answer 72

d) he should undergo surveillance colonoscopy at the interval recommended by his physician

Question 73

A 49 yo man is at his PCP for an annual visit, with no other complaints except fatigue, which he attributes to a busy work schedule. His exam is normal except for pale skin and conjunctivae. Blood work reveals a new moderate microcytic anemia, with iron indices consistent with iron deficiency. He has no family history of colorectal cancer or polyps. What would you suggest next? a) iron supplementation and recheck hemoglobin and iron studies in 3 months b) reduce work hours, get more test, and when he turns 50 should have colorectal cancer screening c) referral to gastroenterologist for evaluation, including colonoscopy d) emergent admission to the hospital for blood transfusion

Answer 73

c) referral to gastroenterologist for evaluation, including colonoscopy

Question 74

A 51 yo woman presents to her PCP for her annual visit. She feels well and has no family history of colorectal cancer. She wants to know if she is at risk for colorectal cancer and what she can do to prevent it or reduce her risk of dying of this disease. What would be the appropriate recommendation? a) since she has no family history of colorectal cancer her risk is very low, so she should not worry about it b) she should consider screening for colorectal cancer now since she is over 50 and has no family history c) she should consider genetic testing; if negative, she's not at risk for colorectal cancer d) she does not have to worry about it, since colon cancer is much less common in women

Answer 74

b) she should consider screening for colorectal cancer now since she is over 50 and has no family history