Disorders of the Large Bowel Flashcards
What is diverticulosis?
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.
Risk factors of diverticulosis?
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).
What can diverticulosis manifest as?
Asx, diverticular spasm, diverticular hemorrhage, and diverticulitis
What is diverticular spasm?
Pain (post-prandial) in LLQ, constipation/abnormal bowel haibts
What causes diverticular hemorrhage?
Stretching of arterioles in diverticula
How does diverticular hemorrhage present?
Bleeding is painless and sudden, generally presenting as hematochezia with symptoms of anemia (fatigue, light-headedness, dyspnea on exertion).
What is diverticulitis?
Diverticulitis is due to inflammation and, potentially, perforation of a diverticulum.
How does diverticulitis present?
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.
TX of diverticular bleeding?
GI bleed workout, stabilize = #1. Can do colonoscopy once bleeding resolves, if still bleeding, arteriogram + embolization.
Workup of diverticulitis?
CBC (leuks), KUB to r/o perforation (free air = perf = exlap), loops in small bowel + air-fluid = obstruction -> surg. nothing –> CT scan.
CT findings of diverticulitis?
CT may show abscess or free air. Mild, Mod, severe.
TX of mil/mod d diverticulitis?
liquid diet or NPO, PO or IV abx. Cipro + metronidazole, or amp/gent + metronidazole.
Barium enema + flex sig in diverticulitis?
NO!!! Risk of perf.
How is colon cancer discovered ideally?
Asx on screening colonoscopy.
Screening guidelines for colon ca?
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.
Alternative screening options for colon ca?
1) Flex sig every 5 yrs + FOBT every 3 yrs.
2) FOBT every year.
Results of colonoscopy categories and f/u?
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
Path of colorectal adenocarcinoma
Arises from premalignant growth from colon.
Risk factors for colon ca?
Age, smoking, alcohol, obesity, processed red meats, inflammatory states (UC, PSC, etc). Genetics
Signs of left-sided colon cancer?
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.
Signs of right-sided colon cancer?
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.
Signs of rectal adenocarcinoma?
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.
Diagnosis of colon ca?
colonoscopy/flex sig/barium enema to visualize whole colon, + pan CT to stage
Mets of colon ca?
40-50% to liver (check LFTs), also bone, lungs, brain, pelvic lymph nodes.
Treatment of colon ca?
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.
Treatment of rectal ca options?
Abdominoperineal resection, Low Anterior Resection, Wide Local Resection, Adjuvant Chemo
Rectal Ca: What is Abdominoperineal resection
For low-lying lesions
Rectal Ca: What is Low Anterior Resection?
For proximal lesions > 10 cm from the anal
verge, a 1° anastomosis between the colon and rectum is created.
Rectal Ca: What is wide local resection?
For small, low-stage, well-differentiated tumors in the lower third of the rectum.
Rectal Ca: Adjuvant Chemo
Used in cases of colon cancer with + nodes.. Chemo agent usually folfox, also folfiri (vegf inhibitors bevacizumab).
F/u of Colon Ca?
Follow with serial CEA levels (diagnostically nonspecific, but useful for
monitoring recurrence), colonoscopy, LFTs, CXR, and abdominal CT (for metastasis).
