Small Bowel Obstruction

Question 1

Conventional radiographs are diagnostic of SBO in only how many percent of cases?

Answer 1

50 to 60% of cases

Question 2

Findings of SBO on conventional radiographs:

Answer 2

1. Dilated loops of small bowel (>3 cm) disproportionate to more distal small bowel or colon
2. Small bowel air-fluid levels that exceed 2.5 cm in width
3. Air-fluid levels at different heights (>5 mm) within the same loop (dynamic air-fluid levels)
4. Two or more air-fluid levels
5. Small bubbles of gas trapped between folds in dilated, fluid filled loops (string of pear sign)

Question 3

Strong evidence of SBO

Answer 3

Dynamic air fluid levels

Question 4

Radiologic sign in which particulate feculent matter mixed with gas bubbles is seen within the dilated small bowel.

Answer 4

“Small-bowel feces” sign

Question 5

Strong CT evidence of SBO

Answer 5

“Small-bowel feces” sign

Question 6

Abrupt beak-like narrowing, without other lesion evident, is indicative of what cause of obstruction?

Answer 6

Adhesion

Question 7

It is associated with changes in the bowel wall and mesentery due to impairment of blood supply.

Answer 7

Strangulation obstruction

Question 8

CT findings of strangulation obstruction

Answer 8

1. Circumferential wall thickening (>3 mm)
2. Edema of the bowel wall (target or halo appearance of lucency in the bowel wall)
3. Lack of enhancement of the bowel wall (most specific sign)
4. Haziness or obliteration of the mesenteric vessels
5. Infiltration of the mesentery with fluid or haemorrhage

Question 9

Most specific sign of strangulation obstruction on CT scan

Answer 9

Lack of enhancement of the bowel wall

Question 10

Small bowel volvulus and closed-loop obstruction are indicated by these signs on CT:

Answer 10

1. Radial distribution of dilated small bowel with mesenteric vessels converging toward a focus of torsion
2. U-shaped or C-shaped dilated small bowel loop
3. “Beak” sign at the site of torsion seen as fusiform tapering of a dilated bowel loop
4. “Whirl” sign of tightly twisted mesentery seen with volvulus

Question 11

The presence of this sign in a patient with SBO correlates strongly with the need for surgery.

Answer 11

Whirl sign

Question 12

It is a major cause of small bowel obstruction in children.

Answer 12

Intussusception

Question 13

It is a cause of mechanical small bowel obstruction that should be suspected in any elderly woman with small bowel obstruction.

Answer 13

Gallstone ileus

Question 14

In gallstone ileus, the gallstone most commonly lodges in what part of the bowel?

Answer 14

Distal ileum

Question 15

Rigler triad consists of?

Answer 15

1. Dilated small bowel loops (80%)
2. Air in the biliary tree or gallbladder (67%)
3. Calcified stone in an ectopic location (50%)