Acute colonic pseudo-obstruction (ACPO) is obstruction of the large bowel without a mechanical cause. The exact mechanism remains incompletely understood but is thought to result from disruption to the autonomic regulation of the colon, typically in the context of hospitalized patients with medical illness, precipitating medications, or recent surgical intervention. This paper presents an unusual case of ACPO in an ambulatory patient with a recently passed renal calculus, explores the anatomy and physiology underlying the autonomic dysfunction theory of ACPO pathogenesis in the context of the case, and provides a 3D reconstruction of the patient\'s CT to illustrate the abrupt caliber change at the splenic flexure characteristic of ACPO.

BACKGROUND: Ogilvie\'s Syndrome or Acute Colonic Pseudo-Obstruction (ACPO) is a rare condition characterized by massive dilatation of the colon in the absence of mechanical obstruction. About 10% of all reported cases are related to Obstetric and Gynaecological procedures, Caesarean section being the commonest associated factor. Acute intestinal dilatation, if not treated, may lead to perforation and faecal peritonitis with consequent high morbidity and mortality.
METHODS: An electronic literature searches were performed in PubMed, EMBASE, Google scholar and hand searches for relevant references were included without any language restriction. All the records reported after year 2002 were included for the full review. We analyzed the quality of the reports and the data was further analyzed for their respective risk factors, clinical features, management methods, morbidity and mortality.
RESULTS: The results from our searches included a total of 125 cases of postpartum ACPO. A total of 66 cases were reported in 37 publications after year 2002. Details of delivery were recorded in 13(19%), clinical manifestations in 49(69%), imaging results in 43(65%) and management described in 100% of the cases. Although 62(92%) cases were following caesarean section, no specific antepartum or intrapartum factors were associated with ACPO. The caesarean sections performed for indications of preeclampsia, multiple pregnancy, antepartum haemorrhage/placenta previa were more in this group of patients who developed ACPO compared to caesarean sections performed for same indication in general population of England and Wales. Abdominal distension and pain were the commonest symptoms, followed by vomiting. Fever was common in patients with perforation. Twenty eight (43%) patients had intestinal perforation or impending perforation, and 31(47%) patients required laparotomy. Conservative management was successful in 33(50%) patients. All patients with a caecal diameter of more than 12cm perforated compared to 3/17 with a diameter of less than 9cm. Most perforations were diagnosed between postoperative day 3 and day 5. Only one case of mortality has been recorded (1.5%).
CONCLUSIONS: No specific risk factors could be identified for postpartum ACPO. A postpartum patient with abdominal distension and pain should have appropriate imaging to rule out colonic dilatation and/or perforation. Perforation may occur with a caecal diameter of less than 9cm but it is more likely if the diameter exceeded 12cm. The mortality risk appears to be low in the postpartum group compared to other patients with ACPO. There is a need for establishing national level databases to capture all the relevant data in a consistent manner, to understand this rare disease process.