Stop for the Stop Light Sign in Colonic Pseudo-Obstruction!

Abstract

Introduction: Acute large-bowel obstruction (ALBO) is an emergency and carries high morbidity and mortality if left untreated. Ogilivie syndrome/Acute colonic pseudo-obstruction (ACPO), can resemble ALBO, and can occur with pelvic surgery/fractures, post-partum state, trauma, systemic infection, cardiac events, transplantation, opiate therapy, and in ICU settings. ACPO is a common source of gastroenterology consultation, however, ALBO must be appropriately excluded to make this diagnosis. We present a patient with incarcerated inguinal hernia (IH) presenting as massive colonic distention, initially thought to be ACPO. Case: A 70 year-old male with a medical history of coronary bypass surgery, cardiomyopathy and prior left inguinal hernia repair was admitted for the treatment of cardiac failure. He developed a cardiac arrest and required invasive ventilation and vasopressor support. Serial abdominal x-rays (AXRs) obtained to investigate worsening abdominal distention with lack of bowel movements (BMs) showed prominent air-filled loops of large bowel measuring up to 10 cm, associated with hypokalemia and leukocytosis. Because of the typical AXRs, cross-sectional imaging was not obtained, and decompression was requested. A presumptive diagnosis of ACPO was made and a rectal tube was placed. Urgent colonoscopy was attempted and the scope was passed with difficulty to 40 cm, revealing an initial spastic segment suspicious for volvulus, with ulcerative changes suspicious for ischemia, and could not be advanced further. The scope tip was palpable in the left inguinal area, with positive skin transillumination, suggesting a strangulated IH. CT showed an ALBO due to proximal sigmoid colon trapped in the left IH and inflammatory changes. An emergent surgical repair of the incarcerated IH with orchiectomy was performed, which resulted in complete resolution of the abdominal distension and prompt return of BMs. Discussion: Both ACPO & ALBO may present with similar clinical features, including abdominal pain & distention, nausea, vomiting & constipation. ACPO is dominated by marked gaseous abdominal dilatation, which is paradoxically well tolerated clinically. Altered/depressed mental status may limit an appropriate history or clinical findings, especially in the ICU setting, and AXRs alone are not sufficient for the diagnosis. CT is the imaging method of choice as it can establish the diagnosis and cause of ALBO. Conclusion: An abrupt stop during colonoscope insertion associated with transillumination in the inguinal region can establish the diagnosis of incarcerated IH, the Stop Light Sign. Before a diagnosis of ACPO is made, CT imaging should be obtained to exclude mechanical ALBO.