Clinical diagnosis
Case 295
【Progress】
The patient, Case 3 had no surgical management because his symptoms were getting better and finally became negative. The following day, he was discharged from hospital.
Case 1. Laparotomy revealed the existence of adhesion between greater omentum and mesentery of small intestine, and small bowel entered the crevice space, twisted and turned color to black, implying difficulty of recovery. After release of the torsion by separating and cutting greater omentum, 60 cm of small bowel was resected for necrosis.
Case 2. Endoscopic laparotomy revealed adhesion of greater omentum along with the previous operative scar of uterine cancer and dilated small intestine with back-red color which entered the crevice space created by adhesion of small mesentery to dorsal side of abdominal wall. Following separation of the adhesion and release of torsion, the dilated small bowel was taken out extrabodily to check the incarcerated bowel which gradually turned recovery of artery pulsation and intestine color. Then, the bowel was returned to the abdominal cavity without resevtion.
Case 4. Laparotomy revealed wide range small bowel with black mural necrosis complicatedly twisted from approximately 90 cm from Treitz ligament. The resection length of small intestine came up to 240 cm.
【Discussion】
Small intestine mesentery extends from Treitz ligament to ileocecal junction containing superior mesenteric artery and superior mesenteric vein and their branches (1-3). It lays a role of ileum and jejunum connecting to the posterior retroperitoneal wall (2). The congenital defect or weakness of small intestine can cause trans-mesenteric hernia that sometimes induces wide-range necrosis of small intestine (4-6). The line from Treitz ligament to ileocecal junction might be one of the keys to realize presence or absence of trans-mesenteric hernia. In Case 3 with probable trans-mesenteric hernia, the hernia gate situates near ileocecal junction, while in Case 4 with operatively-confirmed trans-mesenteric hernia, the hernia gate situates near Treitz ligament. Both patients did not experience intraperitoneal laparotomy in the past. Interestingly, CT showed mesenteric edema in both cases, but no beak sigh in Case 3, while two beak signs in Case 4. Beak sign indicates beak-shaped configuration of small bowel, indicative of marked stenosis or obstruction of small bowel lumen. In Case 3 without beak sign, abdominal pain relieved as time progress, not necessary of laparotomy, while, in Case 4 with two beak signs, laparotomy revealed massive necrosis of wide-range small bowels of 2.4 m. It indicates the imperativeness of the presence of double beak sign when judging the application of surgical management.
Double beak sign implies the closed loop of small intestine; one beak sign indicates the site between the dilated oral small bowel and dilated closed loop small bowel: another beak sign indicates the site between the dilated closed loop small bowel and the constrictive anal small bowel. Then, the presence of two beaks, called double beak sign on non-enhanced CT is crucial for application of surgical management.
Meanwhile, double beak signs (7, 8) detected in Case 1 and Case 2 on non-enhanced CT made the difference of outcomes of bowel necrosis and non-necrosis. Dirty fat sign indicative of mesenteric edema and target sign indicative of mural edema were found in both cases. Namely, CT findings on non-enhanced CT were not useful to differentiate small bowel mural necrosis from non-necrosis.
Closed loop is mere the situation that small bowel is incarcerated in small space that can make double beak signs but it also includes the situation of volvulus or torsion of closed loop small bowel indicative of necrosis-threatening situation. Contrast-enhanced CT might be useful to differentiate ischemic mural damage more precisely.
In Case 3, as there are mesenteric edema and bowel mural edema but not beak sign, radiologic diagnosis was made possible NOMI (non-occlusive mesenteric ischemia).
【Summary】
We presented four cases of acute abdomen: three cases with target sign, dirty fat sign associated with double beak signs and one case with them associated without double beak signs. It is borne in mind that double beak signs are found in acute abdomen of small bowel obstruction and crucial to apply for surgical management, though bowel mural necrosis is always not associated. Torsion or volvulus associated with closed loop is more necrosis-threatening. Contrast-enhanced CT might be useful to predict bowel ischemia.
【References】
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2023.4.11