A Case of Perforated Sigmoid Diverticulitis in Which Gram Staining of Ascitic Fluid Was Useful for Diagnosis

An 85-year-old woman was admitted to our hospital for steroid therapy for relapsing nephrotic syndrome. During hospitalization, she complained of sudden epigastric pain at night. Although there were signs of peritoneal irritation, CT showed a large amount of ascitic fluid, but no free intraperitoneal gas. Gram staining of ascitic fluid obtained by abdominal paracentesis showed Gram-negative rods, which raised a strong suspicion of gastrointestinal perforation and peritonitis. Therefore, emergency surgery was performed. Exploration of the colon showed multiple sigmoid diverticula, one of which was perforated. The patient underwent an emergency Hartmann's procedure. Imaging studies failed to reveal any evidence of gastrointestinal perforation, presenting a diagnostic challenge. However, a physician performed rapid Gram staining of ascitic fluid at night when laboratory technicians were absent, had a strong suspicion of gastrointestinal perforation, and performed emergency surgery. Gram staining is superior in rapidity, and ascitic fluid Gram staining can aid in diagnosis, suggesting that it should be actively performed. We report this case, with a review of the literature on the significance of rapid diagnosis by Gram staining. 1. Introduction The presence of free intraperitoneal air (or pneumoperitoneum) is an important finding in the diagnosis of gastrointestinal perforation. However, pneumoperitoneum is not always associated with gastrointestinal perforation. In the absence of free intraperitoneal air, whether or not to perform surgery must be determined based on abdominal physical findings or other diagnostic means. In particular, the prognosis of patients with large-bowel perforation reportedly depends on the time to surgery, necessitating rapid diagnosis. Herein, we report a case of sigmoid colon perforation diagnosed by rapid, very simple Gram staining of ascitic fluid, with a review of the literature. 2. Case Report The patient was an 85-year-old woman with a chief complaint of epigastric pain and a past history of nephrotic syndrome, hyperlipidemia, diabetes mellitus, and status postbilateral cataract surgery. In 2009, she developed nephrotic syndrome, which was treated with steroid therapy until February 2011, when complete remission was achieved and the therapy was discontinued. No kidney biopsy was performed because of her advanced age, and the cause of her nephrotic syndrome remained unknown. In February 2013, the nephrotic syndrome relapsed, and she was admitted to the Department of Nephrology of our hospital for steroid therapy. Steroid