Ch.4 - Endoscopy

Question 1

What are the contraindications for DRE, anoscopy, and proctoscopy?

Answer 1

Acute anal fissure, incarcerated hemorrhoids, recent anorectal surgery, anal stenosis

Question 2

Most common site of perforation for flex sig?

Answer 2

Distal sigmoid where it angulates from the relatively fixed rectum at the sacral promontory

Question 3

Complications with sodium phosphate preps?

Answer 3

Nephropathy, renal insufficiency from the tubular deposits of phosphate.

Question 4

[Right/Left] sided lesions tend to be more flat and depressed, which leads to more missed lesions

Answer 4

Right is more flat

Question 5

What size lesions found on CT colonoscopy require real colonoscopy?

Answer 5

> 6mm

Question 6

What is the cancer miss rate for barium enema?

Answer 6

22%

Question 7

What is the rate of perforation during colonoscopy for normal ppl?

What about for IBD?

Answer 7

0. 012 - 0.016%

0. 16%

Question 8

What are the three mechanisms for perforation during colonoscopy?

What is the most common site of perforation from colonoscopy? Why?

Second most common site of perforation?

Answer 8

1) direct trauma
2) barotrauma from insufflation
3) from procedures like polypectomy, dilation of strictures, etc

Most common site: sigmoid because it’s the narrowest and the most tortuous - direct trauma

2nd most common: right colon/cecum from barotrauma

Question 9

Difference in management for perforation after therapeutic colonoscopies vs diagnostic colonoscopies

What’s the operation of choice?

Answer 9

Therapeutic more likely to resolve by watching

Diagnostic less likely to resolve on its own

Primary repair or resection and anastomosis

Question 10

What is post-polypectomy syndrome?

When do they present?

Answer 10

Abd pain, fever, wbc after polypectomy but no perforation. Likely from electrocautery

Several days after colonoscopy

Question 11

What is the incidence of post-polypectomy bleeding?

When do they usually present? Why?

Answer 11

~3%

4-6 days after polypectomy when the clot dissolves

Pts on anticoag are surprisingly not at increased risk

Question 12

What is the most consistent risk factor for post-polypectomy bleeding?

Does serrated sessile polyp matter?

Does right/left colon matter?

Answer 12

Polyp size > 2cm (3.8%)
Polyp size < 2cm (0.3%)

Serrated/sessile polyps don’t increase bleeding

Right colon: more likely to bleed

Question 13

What organisms are most commonly associated with c-scope related infections?

Majority of infectious complications from c-scope result from what?

Answer 13

Salmonella, pseudomonads, mycobacterium species.

Mostly from improper cleaning