CT Case 066
A 71-year-old presents with vomiting and abdominal pain and inability to open his bowels. This was preceded by three days of diarrhoea.
He has no previous medical or surgical history.
A CT scan of the abdomen is performed
Describe and interpret the CT images
The CT demonstrates small bowel obstruction in a patient without any history of prior surgery.
There is an abrupt transition zone in the right lower abdomen with drastic change in calibre of the small bowel suggestive of a high-grade obstruction. We also see twisting of the mesentery due to the small bowel rotating on itself.
Intra-operatively, the patient was found to have two bands causing narrowing of the small bowel.
Though congenital bands can be present in adults in any age with small bowel obstruction. Rarely, they can give rise to an internal hernia along the band.
An internal hernia on CT can be seen as a closed loop of small bowel clustered within a hernia sac which may or may not be visible. Since they form a closed loop obstruction, they are more prone to develop gangrene. Development of an internal hernia may not always be apparent on the CT.
The most common locations for a congenital adhesion band are the terminal ileum, root of mesentery, jejunum, liver, and omentum.
Clinical Pearls
Internal hernias account for only 0.5-5.8% of intestinal obstruction.
They are associated with high mortality, up to 50%, and therefore these need to be managed urgently.
Although this case is not related to surgery, there has been an increased incidence of internal hernias due to the number of relatively new surgical procedures now being performed (these include gastric bypass surgery and liver transplantation).
There are two main types of hernias, external and internal.
External hernias are a prolapse of abdominal contents through a defect in the wall of the abdomen or pelvis, and internal hernias are defined by protrusion of a viscus through a normal or abnormal peritoneal or mesenteric aperture within the abdominal cavity (cases 50, 52, 57).
The aperture can be either acquired, such as a postsurgical, traumatic and post-inflammatory, or it can be congenital.
This patient had a diagnostic laparoscopy and division of adhesions. He was found to have congenital adhesions from the proximal jejunum to the right pelvic wall. These adhesions caused this patient’s internal hernia and subsequent bowel obstruction. This is an unusual first presentation in a 71-year-old.
References
- Hartung M. Abdominal CT: closed loop. LITFL
- Martin LC, Merkle EM, Thompson WM. Review of internal hernias: radiographic and clinical findings. AJR Am J Roentgenol. 2006 Mar;186(3):703-17.
TOP 100 CT SERIES
Provisional fellow in emergency radiology, Liverpool hospital, Sydney. Other areas of interest include paediatric and cardiac imaging.
Emergency Medicine Education Fellow at Liverpool Hospital NSW. MBBS (Hons) Monash University. Interests in indigenous health and medical education. When not in the emergency department, can most likely be found running up some mountain training for the next ultramarathon.
Dr Leon Lam FRANZCR MBBS BSci(Med). Clinical Radiologist and Senior Staff Specialist at Liverpool Hospital, Sydney
Sydney-based Emergency Physician (MBBS, FACEM) working at Liverpool Hospital. Passionate about education, trainees and travel. Special interests include radiology, orthopaedics and trauma. Creator of the Sydney Emergency XRay interpretation day (SEXI).