title: Radiographic findings following irrigation of chronic perineal drain with hydrogen peroxide.
abstract: BACKGROUND
  Hydrogen peroxide is a widely available agent used for irrigation and disinfecting. With misuse, significant side effects have been noted ranging from nausea to abdominal cramping to portal venous gas, air embolism and death.
  
  
  METHODS
  We present an 81 year old male who developed a rectovesicular fistula following radiation for metastatic prostate cancer. He had recurrent bleeding and infections and underwent a pelvic exenteration which was complicated by a persistent pelvic abscess requiring placement of a transperineal drainage catheter. After months of persistent drainage, he noted decreased output and irrigated the catheter with 3% hydrogen peroxide. He presented to the emergency room with fever, diarrhea and abdominal cramping but no rebound or guarding. CT depicted free air in the pre-sacral space extending into the retroperitoneum and diffusely throughout the peritoneum. Given his clinical exam and upon review of imaging, we assumed his radiographic findings were related to the direct instillation of hydrogen peroxide into his chronic pelvic cavity.
  
  
  CONCLUSIONS
  Hydrogen peroxide has been used therapeutically for over 100 years. Hydrogen peroxide exerts direct cytotoxicity by corrosion and lipid peroxidation and indirectly by oxygen gas formation. When the oxygen produced exceeds the solubility in the blood, arterial and venous gas embolism occur. It is this sequelae of hydrogen peroxide that is described most frequently in the literature.
  
  
  CONCLUSIONS
  Instillation of hydrogen peroxide into a chronic pelvic cavity resulted in a benign pneumoperitoneum. This effect of hydrogen peroxide is a significant and potentially treatment altering radiographic finding.
authors.affiliation: University of Nebraska Medical Center, Department of Surgery, United States.
authors.forename: Alyson A
authors.initials: AA
authors.lastname: Melin
authors.affiliation: University of Nebraska Medical Center, Department of Radiology, United States.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Heckman
authors.affiliation: University of Nebraska Medical Center, Department of Radiology, United States.
authors.forename: Shahid
authors.initials: S
authors.lastname: Hussain
authors.affiliation: University of Nebraska Medical Center, Department of Surgery, United States.
authors.forename: Jon S
authors.initials: JS
authors.lastname: Thompson
keywords: Benign pneumoperitoneum; Chronic pelvic abscess; Hydrogen peroxide