Management of Malignant Culture-negative Neutrocytic Ascites

Abstract

Introduction: Culture-negative neutrocytic ascites (CNNA) is described as having a similar mortality rate and presentation to spontaneous bacterial peritonitis (SBP). Patients with CNNA are treated the same as patients with SBP, although malignant ascitic fluid may have a neutrocytic predominance in the absence of infection. We present a suggestion for the clinical management of malignant CNNA based on the following case. Case: This is a case of a 50-year-old woman with a history of adenocarcinoma of gastric origin with metastasis to peritoneum, who presented with abdominal distension and abdominal pain. She was hemodynamically stable and afebrile on presentation with physical exam significant for a soft, distended, diffusely tender abdomen without rebound. Labs were notable for WBC of 10 with ascitic fluid showing SAAG 15000 cells with 37% granulocytes, 50% malignant cells with negative cultures. CT abdomen with IV and PO contrast showed no evidence of perforation or abscess ruling out secondary bacterial peritonitis. Antibiotics were broadened to eliminate the possibility of an infectious peritonitis untreated with ceftriaxone alone. She was discharged on a seven-day course of broad antimicrobial coverage. Discussion: The management of malignant culture-negative neutrocytic ascites (CNNA) is not clearly outlined in the literature. In the setting of peritoneal carcinomatosis, we propose a modification to the traditional CNNA management strategy to reduce the burden of hospital days and antibiotic courses. Patients with known malignant ascites should be started on broad antimicrobial coverage for empiric treatment of SBP at the outset, with a repeat tap at 3-5 days to allow sufficient culture growth. Antibiotics should be discontinued without further investigation if the following criteria are met: unchanged clinical picture, negative cultures, unchanged or increased neutrophil count on repeat paracentesis, and secondary bacterial peritonitis has been ruled out with imaging.