Internal hernias: a difficult diagnostic challenge. Review of CT signs and clinical findings

Abstract

Although internal hernias are uncommon, they must be beared in mind in the differential diagnosis in cases of intestinal obstruction, especially in patients with no history of previous surgery or trauma. Because of the high possibility of strangulation and ischemia of the affected loops, internal hernias represent a potentially life-threatening condition and surgical emergency that needs to be quickly recognized and managed promptly. Imaging plays a leading role in the diagnosis and in particular multidetector computed tomography (MDCT), with its thin-section and high-resolution multiplanar reformatted (MPR) images, represents the first line image technique in these patients. The purpose of the present paper is to illustrate the characteristic anatomic location, the clinical findings and the CT appearance associated with main types of internal hernia, including paraduodenal, foramen of Winslow, pericecal, sigmoid-mesocolon- and trans-mesenteric- related, transomental, supravesical and pelvic hernias.

Figure 1.

Drawing shows the anatomic sites of internal hernias: 1a: left paraduodenal hernia, 1b: right paraduodenal hernia, 2: foramen of Winslow hernia; 3: pericecal hernia; 4: sigmoid-mesocolon-related hernia; 5:transmesenteric hernia; 6: transomental hernia; 7:supravesical and pelvic hernia. Asterisk: greater omentum open and reflected laterally

Figure 2.

Closed loop small bowel obstruction. Contrast enhanced axial CT scan shows a radial array of distended small bowel loops (B) with stretched and thickened mesenteric vessels converging to a central point (white arrow). Bowel wall thickening (arrowhead) and mesenteric edema (asterisk) can also be observed.

Figure 3.

Graphic illustration of Landzert’s fossa. The inferior mesenteric vein (IMV) and ascending left colic artery run at the anteromedial edge of the fossa

Figure 4.

Left paraduodenal hernia in a 37-year-old man who presented with nausea and intense abdominal pain. Contrast-enhanced CT scans, axial (a) and (b) and coronal reformatted image (c), show a sac-like mass of clustered dilated small-bowel loops (white circles) between pancreas (P) and stomach (S) with multiple engorged and prominent vessels (white arrow) at the point of entry of the sac

Figure 5.

Graphic illustration of Waldeyer’s fossa. The superior mesenteric artery (SMA) and the superior mesenteric vein (SMV) run along the anteromedial edge of the fossa

Figure 6.

Right paraduodenal hernia in a 83-year-old man with mild abdominal pain and repeated episodes of vomiting for a few hours. Contrast enhanced CT scans, axial (a) and (b) and coronal reformatted image (c) and (d) show an encapsulated cluster of dilated jejunal loops in the right upper quadrant (white circles), lateral to the colon (C) and the II-III portion of duodenum (D) which appears located rightward. Gastric overdistention is also be observed (asterisks). Dilated and converging vessels (white arrow) are seen in the mesentery.

Figure 7.

Graphic illustration of lesser sac and foramen of Winslow. L: liver; S:stomach; TC:transverse colon.

Figure 8.

Foramen of Winslow hernia in a 72-year-old man with intermittent epigastric pain. Contrast-enhanced axial CT scans (a), (b) and (c) show cluster of small bowel loops located in the lesser sac (white circles) between liver and pancreas, posterior to stomach (displaced anteriorly) (asterisk) and anterior to inferior vena cava, which is compressed (white arrows)

Figure 9.

Pericecal hernia in a 80-year-old man with a 1-day history of right lower abdominal pain and vomiting. Contrast-enhanced axial CT scans (a) and (b) show small bowel loops (white arrows) posterior to cecum (C) in right paracolic gutter producing small bowel obstruction

Figure 10.

Sigmoid-mesocolon related hernia in a 80 year-old-man with acute left-sided abdominal pain. Contrast-enhanced axial CT scans (a) and (b) show encapsulated fluid-filled small bowel loops (white circles) protruding toward left lower abdomen through a defect in sigmoid mesocolon located near the left common iliac artery, between sigmoid colon (S) and the left psoas muscle (P). Convergence of engorged vessels grouped together at the entrance of the hernia orifice can also be seen (white arrow)

Figure 11.

Transmesenteric hernia in a 28 year-old man with lower abdominal pain. Contrast-enhanced axial CT scan (a) and sagittal reformatted image (b) show distended ileal loops with poor enhancement of walls (white circles) adjacent to the right abdominal wall. The mesenteric vessels are engorged and crowded (white arrow)

Figure 12.

Petersen hernia in a 40 year-old-woman with nausea and vomiting 6 months after a Roux-en-Y gastric by-pass. Contrast-enhanced axial CT scans (a) and (b) show grouping of small bowel loops near anterior abdominal wall (white circles). A mushroom shape of the herniated mesenteric root (white arrow) and a decreased calibre of SMV with a beaked appearance are also seen (arrowhead)

Figure 13.

Transomental hernia in a 49 year-old man with diffuse abdominal pain. Contrast-enhanced axial CT scan (a) and coronal reformatted image (b) show small bowel loops (white circle) with converging mesenteric vessels and fat in the hernia orifice (white arrow). Omental vessels (arrowheads) running vertically are also seen

Figure 14.

Internal supravesical hernia in a 67-year-old woman with a two-day history of lower abdominal pain. Contrast-enhanced axial CT scan shows intestine loops (white circle) to the left of the urinary bladder.