Can you determine the most likely diagnosis for a 65-year-old woman visiting the ER because of severe abdominal pain? Let’s find out!
A 65-year-old woman presents to the emergency department due to severe abdominal pain. Three months ago, the patient underwent uncomplicated abdominal surgery to resect a large uterine fibroid. Past surgical history is notable for a C-section and cholecystectomy. Temperature is 37.2°C (99.0°F), pulse is 100/min, respirations are 22/min, and blood pressure is 110/60 mm Hg. On physical examination, high-pitched bowel sounds are heard on auscultation and there is guarding and diffuse abdominal tenderness with palpation. A CT of the abdomen and pelvis shows dilated loops of the small bowel with a transition point.
What’s the cause of this patient’s current disorder?
A. Malignancy
B. Paralytic ileus
C. Peritoneal adhesions
D. Uterine leiomyomata
E. Abscess from previous surgery
Scroll down for the correct answer!
The correct answer to today’s USMLE® Step 1 Question is…
C. Peritoneal adhesions
Correct: See Main Explanation.
Incorrect Answer Explanations
A. Malignancy
Incorrect: Malignancies can cause small bowel obstruction. However, given this patient’s history of multiple abdominal surgeries, peritoneal adhesions are more likely the cause of SBO in this patient.
B. Paralytic ileus
Incorrect: Paralytic ileus occurs in the days following an abdominal operation. In contrast, this patient is several months out from her most recent abdominal surgery.
D. Uterine leiomyomata
Incorrect: Large uterine fibroids can potentially cause bowel obstruction, and while this patient has a history of uterine leiomyomata or fibroids, the mass was resected 3 months ago. Recurrence of uterine fibroids after surgery can occur within the first few years after removal, but they do not typically recur within months after surgery.
E. Abscess from previous surgery
Incorrect: While an intra-abdominal abscess can lead to SBO, it would present with an air-fluid level on imaging as well as systemic signs such as fever, nausea, and vomiting. Most intra-abdominal abscesses occur within 1-3 weeks of surgery. It is rare for them to develop several months after surgery.
Main Explanation
This patient presents with diffuse abdominal pain, guarding, and pain with palpation in the setting of a history of multiple abdominal surgeries. Furthermore, physical examination reveals high-pitched bowel sounds, and CT imaging demonstrates dilated bowel loops with a transition point. In combination, these findings indicate a small bowel obstruction (SBO).
While SBO can be caused by several factors, such as a space-occupying malignancy, infection, trauma, or irradiation, the vast majority are caused by peritoneal adhesions. Peritoneal adhesions form in 93 to 100% of patients following abdominal surgery. Adhesions are fibrous connective tissue bands analogous to scar tissue on the skin that form between two or more intra-abdominal organs and/or the inner abdominal wall. These adhesions can cause a lattice of dense connective tissue throughout the abdominal cavity, making future surgical operations difficult. The adhesions can lead to strangulation of small bowel loops and SBO. They can lead to other complications including female infertility and chronic abdominal pain.
Major Takeaway
Small bowel obstruction is a significant complication of peritoneal adhesions which are dense bands of fibrous scar tissue that can develop after abdominal surgeries. They can lead to complications such as SBO, female infertility, chronic abdominal pain, and difficulties with future surgeries.
Want to learn more about this topic?
Read this Osmosis high-yield note: Intestinal adhesions
References
- Welle, N.J., Sajjad, H., Adkins, A., Burns, B. (2021) “Bowel adhesions”. StatPearls [Internet]. Web Address: https://www.ncbi.nlm.nih.gov/books/NBK470544/.
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