Background
Primary infection of the ascitic fluid, diagnosed by ascites fluid with positive culture or with neutrophil count greater than 250
Microbiology
Pathophysiology
Intestinal bacterial overgrowth with increased intestinal permeability leads to translocation to intestinal lymph notes and bloodstream, which results in hematogenous seeding to ascitic fluid
Only occurs in portal hypertension, not in other causes of ascites
Risk Factors
Previous history of SBP
Upper GI bleed
Low sciatic protein
Child-Pugh class
Clinical Manifestations
Asymptomatic in 10%
Fever (70%)
Abdominal pain (60%)
Hepatic encephalopathy (50%)
Abdominal tenderness, usually without rigidity (50%)
Diarrhea (30%)
Ileus (30%)
Shock (20%)
Hypothermia (15%)
Variants
Culture-negative neutrocytic ascites: usually caused by difficult-to-treat organisms like tuberculosis, and non-infective sources
Monomicrobial non-neutrocytic bacterascites: early bacterial colonization
Polymicrobial bacterascites: usually from traumatic paracentesis
Prognosis and Complications
In-hospital mortality of about 33% in hospital
58% 6-month mortality
Investigations
Diagnostic paracentesis with ascitic fluid sent for cell count with differential and culture
Neutrophil count < 250 rules it out
Culture usually monomicrobial
Repeat paracentesis at 48h if ongoing concern
Management
Prevention
Prophylaxis is indicated after even a single episode of SBP
Possibly a role for primary prophylaxis