Disorders of the Large Bowel

Question 1

What is diverticulosis?

Answer 1

Outpouchings of mucosa and submucosa (false diverticula) that herniate through the colonic muscle layers in areas of high intraluminal pressure; most commonly found in the sigmoid colon.

Question 2

Risk factors of diverticulosis?

Answer 2

Diverticulosis is the most common cause of acute lower GI bleeding in patients > 40 years of age. Risk factors include a low-fiber and high-fat diet, advanced age (65% occur in those > 80 years of age), and connective tissue disorders (e.g., Ehlers-Danlos, Marfan’s syndromes).

Question 3

What can diverticulosis manifest as?

Answer 3

Asx, diverticular spasm, diverticular hemorrhage, and diverticulitis

Question 4

What is diverticular spasm?

Answer 4

Pain (post-prandial) in LLQ, constipation/abnormal bowel haibts

Question 5

What causes diverticular hemorrhage?

Answer 5

Stretching of arterioles in diverticula

Question 6

How does diverticular hemorrhage present?

Answer 6

Bleeding is painless and sudden, generally presenting as hematochezia with symptoms of anemia (fatigue, light-headedness, dyspnea on exertion).

Question 7

What is diverticulitis?

Answer 7

Diverticulitis is due to inflammation and, potentially, perforation of a diverticulum.

Question 8

How does diverticulitis present?

Answer 8

Diverticulitis presents as an acute, mild-to-severe, steady or cramping pain commonly localized to the LLQ with fever, nausea, and vomiting. Perforation is a serious complication.

Question 9

TX of diverticular bleeding?

Answer 9

GI bleed workout, stabilize = #1. Can do colonoscopy once bleeding resolves, if still bleeding, arteriogram + embolization.

Question 10

Workup of diverticulitis?

Answer 10

CBC (leuks), KUB to r/o perforation (free air = perf = exlap), loops in small bowel + air-fluid = obstruction -> surg. nothing –> CT scan.

Question 11

CT findings of diverticulitis?

Answer 11

CT may show abscess or free air. Mild, Mod, severe.

Question 12

TX of mil/mod d diverticulitis?

Answer 12

liquid diet or NPO, PO or IV abx. Cipro + metronidazole, or amp/gent + metronidazole.

Question 13

Barium enema + flex sig in diverticulitis?

Answer 13

NO!!! Risk of perf.

Question 14

How is colon cancer discovered ideally?

Answer 14

Asx on screening colonoscopy.

Question 15

Screening guidelines for colon ca?

Answer 15

colonoscopy q 10 yrs starting at age 50, or 10 yrs before age of dx of relative. continue until age 75, only do again if 10 yr mortality is otherwise good.

Question 16

Alternative screening options for colon ca?

Answer 16

1) Flex sig every 5 yrs + FOBT every 3 yrs.

2) FOBT every year.

Question 17

Results of colonoscopy categories and f/u?

Answer 17

0 polyps - come back in 10 yrs
1-2 polyps 1cm or villous or high grade dysplasia - come back in 1-3 yrs
10+ polyps, piecemeal, sessile polyps - come back in months

Question 18

Path of colorectal adenocarcinoma

Answer 18

Arises from premalignant growth from colon.

Question 19

Risk factors for colon ca?

Answer 19

Age, smoking, alcohol, obesity, processed red meats, inflammatory states (UC, PSC, etc). Genetics

Question 20

Signs of left-sided colon cancer?

Answer 20

Typically “apple-core” obstructing masses. Patients complain of a change in bowel habits (e.g., ↓ stool caliber, constipation, obstipation) and/or blood-streaked stools. Obstruction is common.

Question 21

Signs of right-sided colon cancer?

Answer 21

Often bulky, ulcerating masses that → iron-deficiency anemia
from chronic occult blood loss. Patients may complain of weight loss, anorexia, diarrhea, weakness, or vague abdominal pain. Obstruction is rare.

Question 22

Signs of rectal adenocarcinoma?

Answer 22

Usually present with bright red blood per rectum, and may have tenesmus and/or rectal pain. Can coexist with hemorrhoids, so rectal cancer must be ruled out in all patients with rectal bleeding.

Question 23

Diagnosis of colon ca?

Answer 23

colonoscopy/flex sig/barium enema to visualize whole colon, + pan CT to stage

Question 24

Mets of colon ca?

Answer 24

40-50% to liver (check LFTs), also bone, lungs, brain, pelvic lymph nodes.

Question 25

Treatment of colon ca?

Answer 25

Surgical resection of the lesion with 3- to 5-cm margins. The lymphatic drainage and mesentery at the origin of the arterial supply are also resected. 1° anastomosis of bowel can usually be performed.

Question 26

Treatment of rectal ca options?

Answer 26

Abdominoperineal resection, Low Anterior Resection, Wide Local Resection, Adjuvant Chemo

Question 27

Rectal Ca: What is Abdominoperineal resection

Answer 27

For low-lying lesions

Question 28

Rectal Ca: What is Low Anterior Resection?

Answer 28

For proximal lesions > 10 cm from the anal

verge, a 1° anastomosis between the colon and rectum is created.

Question 29

Rectal Ca: What is wide local resection?

Answer 29

For small, low-stage, well-differentiated tumors in the lower third of the rectum.

Question 30

Rectal Ca: Adjuvant Chemo

Answer 30

Used in cases of colon cancer with + nodes.. Chemo agent usually folfox, also folfiri (vegf inhibitors bevacizumab).

Question 31

F/u of Colon Ca?

Answer 31

Follow with serial CEA levels (diagnostically nonspecific, but useful for
monitoring recurrence), colonoscopy, LFTs, CXR, and abdominal CT (for metastasis).