SMALL B

Question 1

Small bowel obstruction: surgical treatment goals

Answer 1

(a) distinguish mechanical obstruction from ileus (b) determine the etiology of the obstruction (c) discriminate partial from complete obstruction, and (d) discriminate simple from strangulating obstruction

Question 2

Intraluminal

Answer 2

Foreign bodies, gallstones, meconium

Question 3

Intramural

Answer 3

Tumors, Crohn’s disease– associated inflammatory strictures

Question 4

Extrinsic

Answer 4

Adhesions, hernias, carcinomatosis Most common etiology is adhesions

Question 5

Intestinal obstruction sx

Answer 5

Crampy intermittent abdominal pain and distension No BM or flatus Previous surgery Hypoactive/hyperactive bowel sounds Metallic quality Ascites– intravascular volume depleted Severe, persistent pain suggests strangulation or perforation

Question 6

Lab results

Answer 6

BUN/CR elevated– >20:1 Hypernatremia Urine electrolytes Hemoconcentration Acidosis Leukocytosis

Question 7

Imaging

Answer 7

Supine and erect abdominal x-ray Erect CXR –> Free air Single-contrast barium enema Small bowel series CT

Question 8

What is the best imaging for SBO and what are the findings?

Answer 8

Abdominal x-ray series -Dilated small bowel loops (> 3 cm) -Air-fluid levels seen on upright films -A paucity of air in colon

Question 9

CT findings

Answer 9

PO contrast, water soluble -Transition zone: dilation proximally, decompression distally (contrast proximally, no contrast distally) -Colon has little gas or fluid -CT shows strangulation

Question 10

CT findings suggestive of strangulation

Answer 10

thickening of the bowel wall pneumatosis intestinalis (air in the bowel wall) portal venous gas mesenteric haziness poor uptake of intravenous contrast into the wall of the affected bowel -IV contrast if compromise of vasculature is suspected

Question 11

Small Bowel Series

Answer 11

Detects low-grade or partial small bowel obstruction Water soluble PO contrast (or in NG tube if vomiting) Sequential x-rays to follow where contrast is traveling

Question 12

Approach to SBO

Answer 12

Management based on: location of obstruction, proximal, mid-gut, distal Level or severity: partial, complete, strangulated, closed-loop

Question 13

Strangulated bowel obstruction

Answer 13

If the intramural pressure becomes high enough, intestinal microvascular perfusion is impaired, leading to intestinal ischemia and, ultimately, necrosis.

Question 14

Partial SBO

Answer 14

only a portion of the intestinal lumen is occluded, allowing passage of some gas and fluid. Continued passage of flatus and/or stool beyond 6 to 12 hours after onset of symptoms is characteristic.

Question 15

Complete SBO

Answer 15

lumen becomes obstructed, gas and fluid accumulate proximally, the bowel distends and intraluminal and intramural pressures rise, and the development of strangulation is more likely.

Question 16

Closed loop obstruction

Answer 16

a segment of intestine is obstructed both proximally and distally (e.g., with volvulus). The accumulating gas and fluid cannot escape either proximally or distally from the obstructed segment, leading to a rapid rise in luminal pressure and a rapid progression to strangulation.

Question 17

Findings of proximal SBO

Answer 17

Vomiting: +++ Character of vomit: bilious Flatus/stool: None past 6-12 hours of onset Abdominal distension: absent Bowel sounds: hyperactive initially, minimal in late stages

Question 18

Findings of distal SBO

Answer 18

Vomiting: + Character of vomit: feculent Flatus/stool: None past 6-12 hours of onset Abdominal distension: +++ Bowel sounds: hyperactive initially, minimal in late stages

Question 19

SBO Conservative tx: initially recommended for

Answer 19

Partial SBO (monitor for 40 hours; if not improving– surgery.) Obstruction in early post-op period (monitor for 2-3 weeks) Intestinal obstruction due to Crohn’s disease Carcinomatosis *Observe closely, undergo serial exams *Watch for: tachycardia, abdominal tenderness, or an increase in white cell count

Question 20

SOB Conservative Tx

Answer 20

-Fluid resuscitation and monitoring (isotonic IVF, monitor urine output, consider invasive hemodynamic monitoring) -NG tube for decompression -Pre-op abx (broad spectrum, gram negatives, and anaerobes) -Serial imaging, exams

Question 21

Surgery: Why?

Answer 21

Minimize risk for bowel strangulation– goal is to operate before onset of irreversible ischemia Look at big clinical picture to determine who should go to OR

Question 22

Surgical options

Answer 22

Exploratory laparotomy Exploratory laparoscopy

Question 23

Findings that suggest viability

Answer 23

Normal color Peristalsis Marginal arterial pulsations

Question 24

Resections: Short lengths

Answer 24

Resect, primary anastomosis of remaining intestine

Question 25

Resections: Large portion

Answer 25

Conservative measures -Get rid of obviously necrotic bowel -Leave bowel of uncertain viability, take a “second look” at 24 hours -Definitive resection if needed

Question 26

Complications of bowel obstruction

Answer 26

Fluid and electrolyte imbalance Dehydration… hypovolemic shock Ischemia of bowel leading to strangulation, necrosis, perforation Peritonitis Sepsis Death

Question 27

Ileus

Answer 27

Alteration in motility of GI tract resulting in a functional obstruction Temporary

Question 28

Paralytic ileus

Answer 28

Minimal abdominal pain, usually continuous Decreased or absent bowel sounds Gas throughout small and large bowel on plain x-ray

Question 29

Return of normal motility

Answer 29

Small-intestinal motility: 24 hours after laparotomy Gastric motility: in 48 hours Colonic motility: in 3-5 days

Question 30

Management of ileus

Answer 30

Limiting oral intake Correcting the underlying inciting factor If vomiting or abdominal distention is prominent- place NG tube Fluid and electrolyte replacement IV fluid maintenance until ileus resolves If the duration of ileus is prolonged, TPN may be required