Chapter 43: Small Intestine- SBO Flashcards

1
Q

What is small bowel obstruction (SBO)?

A

Mechanical obstruction to the passage of intraluminal contents

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2
Q

What are the signs/symptoms?

A
  1. Abdominal discomfort
  2. cramping
  3. nausea
  4. abdominal distention
  5. emesis
  6. high pitched bowel sounds
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3
Q

What lab tests are performed with SBO?

A

Electrolytes, CBC, type and screen, urinalysis

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4
Q

What are classic electrolyte/acid–base findings with proximal
obstruction?

A
  • Hypovolemic
  • hypochloremic
  • hypokalemia
  • alkalosis
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5
Q

What must be ruled out on physical exam in patients with SBO?

A

Incarcerated hernia (also look for surgical scars)

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6
Q

What major AXR findings are associated with SBO?

A

Distended loops of small bowel air-fluid levels on upright film

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7
Q

Define complete SBO

A

Complete obstruction of the lumen

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8
Q

What is the danger of complete SBO?

A

Closed loop strangulation of the bowel leading to bowel necrosis

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9
Q

Define partial SBO

A

Incomplete SBO

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10
Q

What is initial management of all patients with SBO?

A
  • NPO
  • NGT
  • IVF
  • Foley
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11
Q

What tests can differentiate partial from complete bowel
obstruction?

A

CT scan with oral contrast

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12
Q

What are the ABCs of SBO?

A

Causes of SBO:

  1. Adhesions
  2. Bulge (hernias)
  3. Cancer and tumors
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13
Q

What is superior mesenteric artery (SMA) syndrome?

A

Seen with weight loss—SMA compresses duodenum, causing obstruction

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14
Q

What is the treatment of complete SBO?

A

Laparotomy and lysis of adhesions

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15
Q

What is the treatment of incomplete SBO?

A

Initially, conservative treatment with close observation plus NGT decompression

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16
Q

Intraoperatively, how can the level of obstruction be determined in
patients with SBO?

A

Transition from dilated bowel proximal to the decompressed bowel distal to the obstruction

17
Q

What is the most common indication for abdominal surgery in
patients with Crohn’s disease?

A

SBO due to strictures

18
Q

Can a patient have complete SBO and bowel movements and
flatus?

A

Yes; the bowel distal to the obstruction can clear out gas and stool

19
Q

After a small bowel resection, why should the mesenteric defect
always be closed?

A

To prevent an internal hernia

20
Q

What may cause SBO if patient is on Coumadin®?

A

Bowel wall hematoma

21
Q

What is the #1 cause of SBO in adults (industrialized nations)?

A

Postoperative adhesions

22
Q

What is the #1 cause of SBO around the world?

23
Q

What is the #1 cause of SBO in children?

24
Q

What are the signs of strangulated bowel with SBO?

A
  1. Fever
  2. severe/continuous pain
  3. hematemesis
  4. shock
  5. gas in the bowel wall or portal vein
  6. abdominal free air
  7. peritoneal signs
  8. acidosis (increased lactic acid)
25
What are the clinical parameters that will lower the threshold to operate on a partial SBO?
1. Increasing WBC 2. Fever 3. Tachycardia/tachypnea 4. Abdominal pain
26
What is an absolute indication for operation with partial SBO?
1. Peritoneal signs 2. free air on AXR
27
What classic saying is associated with complete SBO?
“Never let the sun set or rise on complete SBO”
28
What condition commonly mimics SBO?
Paralytic ileus (AXR reveals gas distention throughout, including the colon)
29
What is the differential diagnosis of paralytic (nonobstructive) ileus?
* Postoperative ileus after abdominal surgery * (normally resolves in 3 to 5 days) * Electrolyte abnormalities (hypokalemia is most common) * Medications (anticholinergic, narcotics) * Inflammatory intra-abdominal process * Sepsis/shock * Spine injury/spinal cord injury * Retroperitoneal hemorrhage
30
What tumor classically causes SBO due to “mesenteric fibrosis”?
Carcinoid tumor