Medical Image of the Month: Pneumoperitoneum with Rigler’s Sign

Figure 1. CT of the abdomen with contrast showing a large quantity of free air within the peritoneal cavity. The etiology of her free intraperitoneal air was not evident on this imaging study.

Figure 2. An upright chest radiograph performed six months later again demonstrates a large amount of free air under the hemidiaphragms, outlining both the spleen and the superior surface of the liver. Rigler’s sign (air on both the peritoneal and luminal side of bowel wall (arrows) - which clearly delineates the bowel wall) is in noted and supports the diagnosis of free intraperitoneal air.

Clinical Presentation: A 70-year-old Asian-American woman presented to the hospital with a distended and tympanic abdomen. She was otherwise asymptomatic. Her past medical history was significant only for an uncomplicated colonoscopy the previous summer. A CT scan showed free air within the peritoneal cavity (Figure 1). She was managed conservatively without a surgical intervention. After six months without a chest x-ray continued to show free air (Figure 2). She underwent an elective exploratory laparotomy without identification of a cause for her free intraperitoneal air. Her pneumoperitoneum completely resolved on follow up imaging.

Discussion: Pneumoperitoneum is a condition which commonly presents as an acute abdomen (1). Causes are numerous and include penetrating and blunt abdominal trauma, perforation of viscus, diaphragmatic rupture, fistula formation – among other etiologies. Work-up of pneumoperitoneum varies depending on the suspected etiology. In the presence of hemodynamic instability or peritoneal signs, the patient should proceed to an exploratory laparotomy immediately following airway maintenance and resuscitation. In the setting of a perforation or sepsis, broad-spectrum intravenous antibiotics are indicated. Stable patients are managed expectantly with NPO status, intravenous fluids resuscitation, serial vitals/abdominal imaging/labs, and nasogastric tube decompression if indicated for obstructive etiologies.

Rigler’s sign is well-demonstrated in the abdominal radiograph (figure 2). Rigler’s sign is the presence of air on both the luminal and peritoneal side of the bowel wall – which clearly delineates the bowel wall (1). This sign is highly suggestive of free intraperitoneal air. Rigler’s sign can be seen on a supine abdominal radiograph and can be helpful in the identification of free intraperitoneal air in a patient who may be too ill for upright radiographs or CT imaging.

Mohammad A. Mahmoud MD DO, Jonathon P. Mahn DO, and Alexander E. Brahmsteadt, MSIV.

Midwestern University | Arizona College of Osteopathic Medicine

Canyon Vista Medical Center

Sierra Vista, AZ USA

Reference

1. Levine MS, Scheiner JD, Rubesin SE, Laufer I, Herlinger H. Diagnosis of pneumoperitoneum on supine abdominal radiographs. AJR Am J Roentgenol. 1991 Apr;156(4):731-5.

Cite as: Mahmoud MA, Mahn JP, Brahmsteadt AE. Medical image of the month: pneumoperitoneum with Rigler's sign. Southwest J Pulm Crit Care. 2019;19(6):156-7. doi: https://doi.org/10.13175/swjpcc047-19 PDF