Mod 5-6 LB Obstruction and LB Ileus

Question 1

What are most bowel obstructions caused by? What percentage?

Answer 1

• Primary colonic cancers that have grown to proportions that have completely blocked the lumen of the bowel.
• 70%

Question 2

What kind of obstruction is a primary colonic cancer obstruction?

Answer 2

Mechanical obstruction

Question 3

What is more acute, LB obstrution or SB obstruction?

Answer 3

SB obstruction is more acute

*LB obstruction progresses over a longer period of time before the patient presents in significant discomfort.

Question 4

What else causes most cases of LB obstructions besides colonic cancers (2)?

Answer 4

• Diverticular disease
• Volvulus

Question 5

The clinical symptoms of LB obstruction is the same as SB obstruction with the exception of what?

Answer 5

Nausea and vomiting - not as common in LB obstruction.

Question 6

What is the most common symptoms of a LB obstruction?

Answer 6

Pain and distention (to expand by stretching)

Question 7

What does the radiograpic appearance of a LB obstruction depend on?

Answer 7

The function of the ileocecal valve

Question 8

Describe radiographic appearance with a functioning ileocecal valve.

Answer 8

• A large dilated colon and little small bowel gas
• Colon distal to obstruction site is usually free of air and of normal size.

Question 9

Describe radiographic appearance if ileocecal valve is not competent.

Answer 9

Both LB and SB will be gas filled simulating a dynamic ileus.

Question 10

What is a major danger in LB obstruction?

Answer 10

Perforation

Question 11

If the ileocecal valve is competent, the colon becomes what?

Answer 11

A closed loop and increasing pressure cannot be relieved.

Question 12

Where is the most likely site for rupture and when does it commonly occur?

Answer 12

The cecum when it exceeds 10 cm in diameter.

Question 13

Who can tolerate more distention w/o perforation?

Answer 13

Those with chronic obstruction or ileus such as Hirschsprung’s disease (mega colon).

Question 14

What is colonic ileus?

Answer 14

• A distention of the LB w/o signs of obstruction
• The SB is not invovled

Question 15

What does colonic ileus usually accompany or follow?

Answer 15

An acute abdominal inflammatory process or abdominal surgery.

Question 16

What exam may need to be done with LB obstruction? Why?

Answer 16

• Low pressure BE to demonstrate the site of the obstruction
• Identify the cause or determine the cause of distended bowel - ileus or obstruction.

Question 17

What are hte most common sites for LB volvulus? Why?

Answer 17

• Sigmoid and Cecum
• Less firmly attached in the abdomen (i.e. they are more moveable than othe rparts of the LB)

Question 18

What is a volvulus?

Answer 18

LB or SB with the same mechanism - the bowel twists upon itself and causes an obstruction.

Question 19

What are the clinical symptoms of a LB volvulus?

Answer 19

Same as LB obstruction (or LB ileus???)

Question 20

What is the effect of radiographic technique in volvulus?

Answer 20

Obstruction produces air and air is easy to penetrate. Decrease technique.

Question 21

If you were looking at a radiograph wt both bowels filled with air, what simple question would help make an initial decision about whether the process is mechanical obstruction or dynamic ileus?

Answer 21

Has the patient had surgery in the past few days?