A paraduodenal hernia revealed by bowel obstruction: case report and literature review

Internal hernias are defined as the protrusion of abdominal viscera through an aperture in the intraperitoneal recesses, they are considered as a rare cause of intestinal obstruction. The paraduodenal hernias are the most common type of congenital hernia especially the left-sided ones. We report a case of a 46 year-old man presenting a left paraduodenal hernia with acute small bowel obstruction, which was firstly (preoperatively) assigned to a tumoral cause.


Introduction
Internal hernias are defined by the protrusion of a viscus through a normal or abnormal peritoneal or mesenteric aperture within the confines of the peritoneal cavity [1]. They can be acquired following a surgical procedure or trauma and to congenital peritoneal defect [2].
They may remain silent, detected incidentally at laparotomy or at autopsy, or lead to intestinal obstruction. Paraduodenal hernias, the most common type, account for more than 50% of all cases and responsible for < 1% of small bowel obstruction [2,3]. The left-sided PDH, more common, occurs generally in males [3] and has got 50% lifetime risk of developing small bowel obstruction and 20-50% rate of mortality [3]. We report the case of a 46 year-old man with signs of acute bowel obstruction diagnosed preoperatively to be due to a tumoral cause, but the emergency laparotomy revealed an obstructed left paraduodenal hernia (LPDH).

Discussion
Internal hernias are considered as an unusual cause of small-bowel obstruction, with a reported incidence of less than 2% [4]. Although Paraduodenal hernias, type of congenital hernias, are rare circumstance (0.2 -0.9%), they account for 53% of all internal hernias [2]. The LPDH is 3 times more common than its right homologue [3].
Usually, males are more affected than females (3:1) and the fourthsixth decade of life are the most involved [5,6].  [5]. Many of the paraduodenal hernia can be diagnosed incidentally at laparotomy, autopsy or during radiological investigation for an unrelated disease [14]. The Page number not for citation purposes 3 preoperative diagnosis of asymptomatic paraduodenal hernia is difficult, so imaging can be of no help if it is not done during symptomatic episode [3]. Among 45 recently reported cases of symptomatic left paraduodenal hernias, 19 cases (43%) were diagnosed before surgery [7]. Plain X-ray (first-line imaging exam in emergency department) may show signs of bowel obstruction, a mass effect with displacement of other abdominal organs by herniated bowel segment [4].
Abdominal CT scan is the standard for the diagnosis of the left paraduodenal hernia. It may show different typical radiological aspects related to hernia: a "cluster" of small bowel loops, an encapsulated saclike mass at level of the ligament of Treitz, a depression of the duodenal-jejunal junction, a mass effect on the rear wall of the stomach, congestion and overcrowding of the mesenteric vessels with frequent right displacement of the main mesenteric trunk and anterior upwards displacement of the inferior mesenteric vein, which delimits the hernial defect and a depression of the transverse colon [5,9,15]. Angiography may be helpful in demonstrating displacement or twisting of blood vessels [4].
Diagnostic laparoscopy for verification of diagnosis and simultaneous surgical intervention can be tried in cases that cannot be diagnosed with radiological method [16]. Surgery is always indicated (necessary), even in asymptomatic cases, because of the increased risk for a life-long incarcerated or strangulated hernia, which represent acute complications related to a 20 -50% mortality rate [5].
Treatment is based on manual reduction of bowel loops with surgical repair of the abnormal defect: closure of hernial defect with continuous or interrupted suture, enlargement of defect or resection of the sac [17].

Competing interests
The authors declare no conflict of interests.

Authors' contributions
Mustapha Ben Moussa: study design, data collection, statistical analysis, data interpretation, manuscript preparation, literature search, and writing. The other authors: study design, data collection and interpretation. All authors have read and agreed to the final manuscript.