Clinical History
Young cocaine-addicted North African immigrant with previous appendectomy during childhood, complaining of progressive, diffuse abdominal pain and inability to pass stools since 6 days.
Tympanic abdominal distension with diffuse tenderness at superficial palpation found during physical examination, with present peristalsis and questionable Blumberg sign. No significantly altered laboratory tests.
Imaging Findings
At admission, plain abdominal radiographs detected moderate gaseous distension of the right and transverse colon up to the splenic flexure, with paucity of gas distally. Twenty-four hours later, follow-up radiographs identified significant increase of colonic and ileal distension with prominent gas-fluid levels consistent with mechanical obstruction, up to the fixed splenic flexure.
Urgent colonoscopy reached the left colonic flexure, found overdistended with blueish – oedematous mucosal changes consistent with ischemia, but invalicable due to lumen invisibility.
Contrast-enhanced MDCT with multiplanar reformations easily identified laterally transdiaphragmatic herniated omental fat and splenic flexure causing upstream obstruction.
Laparotomic exploration confirmed intrathoracic herniation of entire epiploon and left colonic flexure: the surgeon repositioned them into the abdominal compartment, with resection of 10 cm of ischemic colon.
Upon recovery, at further questioning the patient admitted a penetrating thoraco-abdominal trauma (stab wound from knife assault) several years earlier.
Discussion
In the vast majority of patients, large bowel obstruction is due to colon carcinoma, volvulus or diverticulitis; uncommon causes include fecal impaction, inflammatory bowel disease and previous irradiation [1]. Colonic herniation through a traumatic diaphragm defect is an exceptional cause of mechanical obstruction, unsuspected or misdiagnosed particularly when history of trauma is remote or missing [2].
Diaphragm rupture (DR) occurs in 3-7% of thoracoabdominal traumas, more frequently (2:1) with penetrating rather than blunt ones. In up to 60% of traumatized patients, DR remains unrecognized because of its subtle or absent clinical and radiologic manifestations [2-4].
Undiagnosed post-traumatic DRs may manifest clinically after years or decades. Diagnosis of serious delayed complications (particularly gastrointestinal obstruction) is challenging because of their vague symptoms or severe acute presentation; the high mortality rate from strangulation makes prompt and correct diagnosis and surgical treatment imperative [2, 3, 5, 6].
The possibility of DR causing colonic entrapment should be considered even when history of penetrating (gunshot or stab) trauma is vague or remote; the relatively unprotected left hemidiaphragm is more frequently injured, since most assailers are right-handed [3, 6].
Abdominal plain radiographs are usually obtained as the first diagnostic procedure in patients with suspected intestinal obstruction. Radiographs interpretation is essential in promptly diagnosing this uncommon urgent condition: as in our patient, mild to moderate gas-filled colon dilatation is seen up to the splenic flexure, often increasing over serial studies, with paucity of gas distally. Other findings include apparent elevation or diaphragm contour abnormalities, ipsilateral lung base hypoaeration or small pleural effusion. Sometimes colonic herniation above the gastric bubble or the diaphragm is seen, whereas contrast enema usually reveals obstruction at the level of the splenic flexure [1, 3, 6].
Currently, MDCT acquisition with multiplanar reformations has dramatically improved the diagnosis of DR: signs include discontinuity of diaphragm or crus, abnormal elevation or intrathoracic herniation of abdominal organs, the so-called CT “collar sign” (a waist-like constriction of omentum and/or abdominal viscera at the site of herniation) and “dependent viscera sign” (absent lung interposed between chest wall and upper portion of abdominal organs) [2, 4]. Furthermore, contrast-enhanced MDCT in intestinal obstructive conditions allows identification of level and transition point, severity and cause, plus the identification of complications particularly strangulation: in this case, bowel ischaemia found at surgery was not preoperatively identified at CT probably because of the time elapsed between diagnostic examination and laparotomy [1, 7].
Differential Diagnosis List
Left-sided post-traumatic transdiaphragmatic herniation causing acute colonic obstruction.
Diaphragm eventration
Congenital diaphragm hernia
Splenic flexure volvulus
Obstruction from adhesions
Inflammatory bowel disease
Final Diagnosis
Left-sided post-traumatic transdiaphragmatic herniation causing acute colonic obstruction.
