Lecture 20 - Diseases of the Colon and Rectum

Question 1

Internal Hemorrhoids most commonly form from the _____ _____vein, which is a branch of the ______ vein. With this in mind, what is the underlying cause?

Answer 1

Inferior Mesenteric Vein (IMV)

Portal vein

Portal hypertension is the underlying cause.

Question 2

Acute self-limited colitis showing Petechial hemorrhage is usually _______ (viral or bacterial?)

Answer 2

Bacterial

Question 3

___ ______ is the cause of Pseudomembranous colitis.

Answer 3

C. diff

Question 4

Hemorrhagic colitis is caused by ______ (0:157:H7). It is a ______ (localized or diffuse?) colitis with hemorrhagic mucosa.

Answer 4

EHEC

Diffuse

Question 5

Amebiasis, an ulcerative (flask-shaped ulcers) colitis typically involving the ileocecal valve/area and ascending colon, is caused by _____ _______. This is a trophozoite organism that consumes ______ (erythrophagocytosis). These patients are at risk for developing ulcers in the _____ as well.

Answer 5

Entamoeba histolytica

RBCs

Liver

Question 6

Schistosomiasis (Schistosoma colitis) is caused by Schistosoma mansoni –> the parasite lodges in the _______, which supplies the descending and sigmoid colon. This organism is endemic to ____ _____ and the middle east.

Answer 6

IMA (Inferior Mesenteric Artery)

Puerto Rico and the middle east

Question 7

Ulcerative colitis begins in the ______ and progresses to the _____ (usually spares the anus).

How does this localization compare to Crohn’s disease?

Answer 7

While Ulcerative Colits travels proimally and doesn’t reach the terminal Ileum, Crohn’s begins in the terminal Ileum and travels DISTALLY to the cecum and CAN involve the Anus.

Question 8

80% of Ulcerative colitis patients are positive for __-_____.

Answer 8

p-ANCA

Question 9

Crohn’s ulcers are discrete, _____ ulcers, while those in Ulcerative colitis are broad. Keep in mind Crohn’s is a transmural disease, so the ulcers can lead to fissures and _____ tracts with other organs (i.e. bowel, bladder, vagina, and abdominal wall).

Answer 9

Aphthous

Fistula

Question 10

Tubular Adenomas result in _____ polyps, while Villous Adenomas result in ______ polyps. Which are easier to treat/have LESSER risk for carcinoma development?

Answer 10

Pedunculated

Sessile (broad base)

Pedunculated easier to treat/less carcinoma risk

Question 11

Treatment of Metastatic Colon Cancer might include monoclonal Ab (MAB) therapy using an ______ Ab, as this receptor activates KRAS (part of the aberrant cancer cell growth pathway). Pathologist have to be sure KRAS is not auto-activated if this therapy is to work.

Answer 11

EGFR