Spontaneous bacterial peritonitis
From IDWiki
Background
- Primary infection of the ascitic fluid, diagnosed by ascites fluid with positive culture or with neutrophil count greater than 250
Microbiology
- Escherichia coli (43%)
- Klebsiella pneumoniae (11%)
- Streptococcus pneumoniae (9%), particularly affecting people with HIV and prepubertal girls
- Other streptococcal species (19%)
- Enterobacteriaceae (4%)
- Staphylococcus (3%)
- Pseudomonas (1%)
- Miscellaneous (10%)
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
- Ceftriaxone 1-2g IV q24h + albumin 1.5 g/kg on day 1 and 1 g/kg on day 3
Prevention
- Prophylaxis is indicated after even a single episode of SBP
- TMP-SMX SS or DS PO daily
- Norfloxacin 400 mg PO daily
- Ciprofloxacin 500 mg PO daily
- Possibly a role for primary prophylaxis
