Non-traumatic bladder rupture showing less than 10 Hounsfield units of ascites.

Aim: Bladder ruptures are commonly misdiagnosed as gastrointestinal perforations or intestinal ischemia. If a diagnosis is made preoperatively, conservative treatment is a safe and effective option. We evaluated the validity of using the attenuation value of ascites, measured by non-contrast computed tomography (CT), to identify patients with bladder ruptures. Methods: A retrospective search of our hospital database identified 7 patients with confirmed bladder ruptures between 2007 and 2013. We also enrolled 18 patients with gastrointestinal perforations and 10 patients with intestinal ischemia with detectable ascites on abdominal CT that had undergone emergency exploratory laparotomy between 2007 and 2013. Between-group comparisons of attenuation values of ascites as obtained by non-contrast CT were evaluated. Results: All attenuation values were less than 10 Hounsfield units (HU) in bladder rupture patients. Moreover, the attenuation value of ascites in cases of bladder rupture (median, 5.7; range, 3.1-6.1) was significantly lower than in cases of gastrointestinal perforation (median, 14.7; range, 4.7-25.4) and intestinal ischemia (median, 13.3; range, 6.0-18.1) (P = 0.004 for both comparisons). Conclusion: Bladder rupture mimics gastrointestinal perforation and intestinal ischemia with acute kidney injury. Therefore, the diagnosis of bladder rupture using the attenuation value of ascites on non-contrast CT is both useful and highly significant. We suggest that bladder rupture be considered in the differential diagnosis of patients presenting with acute abdominal pain and attenuation values of ascites of less than 10 Hounsfield units.