Culture negative neutrocytic ascites versus culture positive spontaneous bacterial peritonitis; Is there a Difference; A Multi-Centric Study

Background: There are two variants of spontaneous bacterial peritonitis (SBP) include, culture negative neutrocytic ascites (CNNA) and culture positive SBP. Some suggested that, the clinical presentation of two variants is nearly similar, however, other reported that, patients with culture positive have a more severe course and higher mortality than CNNA. The aim of this study is to determine the clinical characteristics and predictors of CNNA in comparison to culture positive SBP. Materials and methods: This study included 300 consecutive patients with HCV related cirrhotic ascites. All patients underwent abdominal paracentesis and the ascitic fluid was processed for cell count and culture. Clinical and laboratory parameters of these patients were recorded at index admission. Results: Out of 300 patients included in the study, 150 patients had SBP. Among the 150 patients with SBP, 100 patients were culture positive SBP (culture positive SBP with ascitic fluid PMNL ≥250 cells/m3) and 50 patients were CNNA (culture negative SBP with ascitic fluid PMNL ≥250 cells/m3). Compared to patients with culture positive SBP, patients with CNNA showed, a significant decrease as regards, fever, prevalence of DM, hepatic encephalopathy, platelets, blood PMNL and ascetic PMNL. Logistic regression analysis demonstrated that, decreased platelets count, blood PMNL and ascetic PMNL were independent predictor factors for CNNA. Conclusion: Patients with CNNA have a lower incidence of fever, prevalence of diabetes mellitus, hepatic encephalopathy, blood PMNL and ascetic PMNL versus culture positive SBP. Independent predictors of culture negative SBP are decreased platelets, blood PMNL and ascetic PMNL. Introduction In cirrhotic patients, bacterial infections of ascites increase the morbidity and mortality . Bacterial infections occur in 25% to 30% in cirrhotic patients and are responsible for 30% to 50% of the mortality in patients with chronic liver disease . In abscence of any evidence of external or intra-abdominal source of infection, two variants of spontaneous bacterial peritonitis (SBP) have been described, the first is spontaneous bacterial peritonitis diagnosed by positive ascitic fluid culture associated with ascitic PMNL count >250/mm and the second is patients have culture-negative SBP with an ascitic fluid neutrophil count ≥250 cells/mm3 named culture negative neutrocytic ascites (CNNA). Due to the high rate of culture negativity, reportedly up to 60%, SBP is diagnosed based on the ascitic fluid polymorphonuclear (PMN) count. Culture negative neutrocytic ascites, which is considered to be a variant of SBP, was first defined in 1984 . The outpatient prevalence of SBP is 1.5–3.5% and exceeds 10% in hospitalized patients . When first described, its mortality exceeded 90%, but it has been reduced to approximately 20% with early diagnosis and treatment. Several studies have reported that, microorganisms are present in only 40–73% of SBP cases by using blood culture bottles . The most prevalent types of microorganism isolated from patient ascetic fluid with SBP are Escherichia coli (∼70%) and Klebsiella species . While culturing bacteria needs time, delays in antibacterial treatment can be fatal and result in the death of the patient from overwhelming infection. However, ascites culture is essential to guide antibiotic therapy. Up to the present time, only a scarce research, including a small number of patients has compared the clinical course and prognosis of CNNA and SBP . Runyon and Hoefs first described the similarities between CNNA and SBP in terms of clinical signs, symptoms and mortality, In contrast, some observed lower mortality in patients with CNNA than those with SBP and concluded that CNNA was a less severe variant of SBP . ________________________