10.4: Intestinal Obstruction

ACR – Gastrointestinal – Suspected Small Bowel Obstruction

Case 1

Adhesions

Clinical:

History – This patient has had numerous ventriculo-peritoneal shunts. He has had many abdominal surgeries for revisions of the shunt tubing. No other significant history.

Symptoms – Abdominal pain and bloating. Diminished appetite. No flatus or bowel movements for 24 hours. Vomiting watery green fluid for 12 hours.

Physical – The abdomen was distended and mildly, diffusely tender. The bowel sounds were infrequent and high-pitched. The abdomen was tympanitic. No rebound or guarding. Scars were seen from his previous surgeries.

DDx:

Suspected Small Bowel Obstruction

Imaging Recommendation

ACR–Gastrointestinal – Suspected Small Bowel Obstruction, Variant 1

Three views of the Abdomen

CT of the Abdomen

ODIN Link for Small Bowel Obstruction images (3 Views of the Abdomen), Figure 10.6A and B: mistr.usask.ca/odin/?caseID=20170410113920578

Figure 10.6A Abdominal x-ray, supine, suspicious for SBO

Figure 10.6B Abdominal x-ray, upright, suspicious for SBO

Imaging Assessment

Findings:

There was a paucity of bowel gas in the colon. The small bowel was dilated and there were multiple air-fluid levels (> 3 in number) in the small intestine. No calculi seen. The ventriculo-peritoneal shunt tubing was noted.

Interpretation:

Suspicious for high-grade, or complete, small bowel obstruction.

Diagnosis:

Adhesions, small bowel obstruction from restrictive band.

Discussion:

An abnormality in the small bowel lumen, the small bowel wall, or an abnormality extrinsic to the small bowel can cause a blockage of the lumen. This prevents antegrade passage of gas and fluid. Initially, the small bowel increases peristaltic effort to move the contents forward (hyperperistalsis, high-pitched bowel sounds), then later the peristalsis ceases.

The hyperperistalsis clears the bowel downstream of the obstruction resulting in a relatively clear distal bowel (sigmoid colon, rectum).

Causes of small bowel obstruction include:

• Adhesions after previous abdominal or pelvic surgery
• Inflammatory bowel disease
• Hernias
• Gallstones
• Malignancy
• Ingested foreign body
• Intussusception – more common in children

X-ray findings may include:

• Dilated bowel – small bowel > 2.5 – 3 cm, cecum > 10 cm, transverse colon > 6 cm, sigmoid colon > 4cm
• Gas and fluid in the bowel.
• Air-fluid levels in small bowel > 3 in number
• Less gas and fluid in the bowel downstream of obstruction.

Case 2

Ventral Abdominal Hernia

Clinical:

History – This patient had a previous laparotomy for a perforated diverticulum 10 years ago. A noticeable hernia was present in the ventral abdomen and it was noted to have enlarged over the last two years.

Symptoms – Abdominal pain and bloating. Diminished appetite. No flatus or bowel movements for 48 hours. Vomiting watery green fluid for 24 hours.

Physical – The abdomen was distended and mildly, diffusely tender. The bowel sounds were infrequent and high-pitched. The abdomen was tympanitic. A large, firm, mass was noted in the ventral abdominal wall. It was not particularly tender to palpation. No rebound or guarding.

DDx:

Suspected Small Bowel Obstruction

Ileus

Bowel Perforation

Imaging Recommendation

ACR–Gastrointestinal – Suspected Small Bowel Obstruction, Variant 1

Three views of the Abdomen

CT of the Abdomen

ODIN Link to Abdominal Wall Mass with Small Bowel Obstruction images (Ultrasound, 2 Views of the Abdomen, and CT), Figure 10.7A and B: mistr.usask.ca/odin/?caseID=20170410112613962

Figure 10.7A Ultrasound of Abdomen displaying a mass in the abdominal wall fat

Figure 10.7B CT Scan of the Abdomen displaying a mass in the abdominal wall and very dilated small intestine

Imaging Assessment

Findings:

Ultrasound – A mixed echogenicity mass is seen in the lower mid abdomen. There is suspicion for a fat containing intestine within the hernia sac. No calculi seen.

CT – There was a soft tissue mass in the lower, ventral, abdominal wall, subcutaneous fat. This has the appearance of a hernia. There was intestine in the hernia sac. The visualized small intestine was dilated, consistent with a small bowel obstruction.

Interpretation:

Moderate grade small bowel obstruction.

Diagnosis:

The patient had a ventral, bowel containing hernia, with small bowel obstruction secondary to entrapment of the bowel in the hernia sac (incarceration).

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Attributions

Figure 10.6A Abdominal x-ray, supine, suspicious for SBO by Dr. Brent Burbridge MD, FRCPC, University Medical Imaging Consultants, College of Medicine, University of Saskatchewan is used under a CC-BY-NC-SA 4.0 license.

Figure 10.6B Abdominal x-ray, decubitus, suspicious for SBO by Dr. Brent Burbridge MD, FRCPC, University Medical Imaging Consultants, College of Medicine, University of Saskatchewan is used under a CC-BY-NC-SA 4.0 license.

Figure 10.7A Ultrasound of Abdomen displaying a mass in the abdominal wall fat by Dr. Brent Burbridge MD, FRCPC, University Medical Imaging Consultants, College of Medicine, University of Saskatchewan is used under a CC-BY-NC-SA 4.0 license.

Figure 10.7B CT Scan of the Abdomen displaying a mass in the abdominal wall by Dr. Brent Burbridge MD, FRCPC, University Medical Imaging Consultants, College of Medicine, University of Saskatchewan is used under a CC-BY-NC-SA 4.0 license.