From the Guidelines
Infection in ascites is defined by a neutrophil count of 250 cells/mm³ or greater in the ascitic fluid, which corresponds to approximately 2-3 neutrophils per high-powered field (HPF). This threshold is specifically used to diagnose spontaneous bacterial peritonitis (SBP), a serious infection of ascitic fluid without an evident intra-abdominal source 1. When examining ascitic fluid, it's essential to note that the absolute neutrophil count is more reliable than the HPF count for diagnosis.
Some key points to consider in the diagnosis and management of SBP include:
- Diagnostic paracentesis should be carried out without delay to rule out SBP in all cirrhotic patients with ascites on hospital admission 1.
- Ascitic fluid culture with bedside inoculation of blood culture bottles should be performed to guide the choice of antibiotic treatment when SBP is suspected 1.
- Immediate empirical antibiotic therapy should be determined with due consideration of the context of SBP, severity of infection, and local bacterial resistance profile 1.
- A positive bacterial culture from the ascitic fluid confirms infection, though treatment should not be delayed while awaiting culture results if the neutrophil count meets the diagnostic threshold.
Early recognition and prompt antibiotic treatment are essential, as SBP carries significant mortality risk, particularly in patients with cirrhosis who commonly develop ascites 1. The guidelines recommend a strong consideration for prophylactic antibiotic treatment in patients presenting with gastrointestinal bleeding and underlying ascites due to cirrhosis to prevent the development of SBP 1.
From the Research
Definition of Infection for Ascites
- The number of nucleated cells per high powered field that defines infection for ascites is not explicitly stated in the provided studies 2, 3, 4, 5, 6.
- However, study 3 mentions that ascites neutrophil count is an important factor in diagnosing spontaneous bacterial peritonitis (SBP), with a higher count indicating a higher likelihood of infection.
- Study 4 discusses the use of ascitic fluid neutrophil count as a diagnostic tool, but does not provide a specific threshold for defining infection.
Diagnostic Criteria for Spontaneous Bacterial Peritonitis (SBP)
- Study 3 compares the clinical characteristics and outcomes of SBP and culture-negative neutrocytic ascites, but does not provide a clear definition of the number of nucleated cells per high powered field that defines infection.
- Study 2 discusses the management of ascites, SBP, and hepatorenal syndrome, but does not provide specific diagnostic criteria for SBP in terms of nucleated cells per high powered field.
Limitations of Current Studies
- None of the provided studies 2, 3, 4, 5, 6 provide a clear answer to the question of how many nucleated cells per high powered field defines infection for ascites.
- Further research may be needed to establish a specific threshold for defining infection in ascites based on the number of nucleated cells per high powered field 2, 3, 4, 5, 6.