Unusual difficulty in identifying the source of infection leading to the misdiagnosis of secondary peritonitis: A case report and review of the literature

Severe intra-abdominal infections present a significant challenge in emergency surgery worldwide. Accurate identification of the cause of peritonitis and prompt emergency surgery are crucial, as misdiagnosis can lead to delayed treatment, increased morbidity, and potential mortality. We present a rare case of secondary peritonitis initially misdiagnosed in a patient with a liver abscess. Despite comprehensive intraoperative examination, a definitive cause was not identified initially, leading to a diagnosis of spontaneous bacterial peritonitis. The patient subsequently underwent repeat surgery, which revealed a microperforation of a liver abscess into the abdominal cavity. However, the microperforation had been tightly sealed with a fibrin coating. This clinical case highlights an unusual intraoperative diagnostic challenge involving secondary peritonitis caused by microperforation of a liver abscess, which may have been associated with previous blunt abdominal trauma. The clinical significance of this case lies not in the presumed post-traumatic origin of the abscess, but rather in the diagnostic difficulty encountered during surgery. In particular, the unusual presentation and the difficulty in identifying the source of infection initially led to a misdiagnosis of the underlying cause of the secondary peritonitis. This case exemplifies a rare cause of peritonitis, highlighting the challenges of detecting the abscess cavity via ultrasound after a small liver abscess has emptied into the abdominal cavity. Thus, we believe the distinctive feature of this case was the presence of a small, fibrin-covered defect of liver abscess that remained undetected during the initial laparotomy, compounded by the fact that the patient initially denied any history of previous abdominal trauma. This case emphasizes the difficulties of intraoperative diagnosis and the critical importance of accurately determining the source of peritonitis during surgery. Prompt emergency intervention is crucial to prevent serious complications and reduce mortality associated with peritonitis.