Peritonitis, Acute
Basics
Description
- Definition: inflammation of the peritoneum
- Classification:
- Aseptic: chemical irritation or systemic inflammation of peritoneum
- Bacterial: infection of peritoneal fluid
- Bacterial peritonitis types:
- Primary/spontaneous bacterial peritonitis (SBP): infection of ascitic fluid in the absence of an intra-abdominal source
- Secondary bacterial peritonitis: infection of ascitic fluid from a detectable intra-abdominal source
- Secondary bacterial peritonitis can be further classified as either perforation peritonitis or nonperforation peritonitis.
- Tertiary bacterial peritonitis: >48 hours of infection despite source control
- Peritoneal dialysis–associated peritonitis
- Perforated appendicitis and chronic peritoneal dialysis are the most common cause leading to acute peritonitis in children.
Epidemiology
Incidence
- In cirrhotic patients with ascites, the annual incidence of SBP is 10–25%.
- 25–75% of patients with secondary bacterial peritonitis progress to tertiary peritonitis.
Prevalence
- SBP: In asymptomatic patients with cirrhosis and ascites, the prevalence of SBP is <4% in outpatients. Nosocomial rates are 10%.
- In patients with cirrhosis and ascites, 5% of peritonitis is secondary.
- Secondary peritonitis is the most common cause of sepsis in surgical ICU patients.
- PD peritonitis is the primary reason for switching from PD to hemodialysis (HD).
- PD peritonitis in children is more common than in adults.
Etiology and Pathophysiology
- Mechanism
- SBP:
- Bacterial translocation via lymphatic spread through mesenteric lymph nodes
- Often develops in the setting of large-volume ascites in patients with advanced cirrhosis
- Cirrhotic patients have:
- Alterations to gut microbiota with higher prevalence of pathogenic organisms
- Small intestinal bacterial overgrowth (SIBO) and increased intestinal mucosal permeability to bacteria
- Decreased cellular and humoral immunity limiting peritoneal bacterial clearance
- Secondary:
- Translocation of bacteria from inflamed or perforated intraperitoneal (IP) organs or introduction of bacterial through instrumentation
- Tertiary: evolves from secondary peritonitis
- PD peritonitis:
- Contamination with pathogenic skin flora during exchanges or exit-site infection
- SBP:
- Microbiology
- SBP. Most cases (>90%) of SBP are monomicrobial.
- Most common gram-negative pathogens are Escherichia coli (33%) and Klebsiella spp. (8%).
- Most common gram-positive pathogens are Streptococcus spp. (15%) and Staphylococcus aureus (13%).
- Secondary: perforation of a viscus, small bowel strangulation, necrotizing pancreatitis. Organism depends on cause of peritonitis; gram-positive organisms more common with upper GI pathology, whereas gram-negative organisms more common with lower GI pathology. Common species include E. coli, Klebsiella, Proteus, Streptococcus, Enterococcus, Bacteroides, and Clostridium.
- PD peritonitis is most commonly due to Staphylococcus epidermidis and S. aureus.
- SBP. Most cases (>90%) of SBP are monomicrobial.
Risk Factors
- SBP: advanced cirrhosis with ascites, malnutrition, upper GI bleed, PPI usage, and prior SBP
- Acid suppression (most commonly with PPIs) promotes gut bacterial growth and translocation.
- 70% of SBP cases are in patients with Child-Pugh class C cirrhosis.
- Low ascites protein (<1.0 g/dL) increases risk.
- Secondary:
- Helicobacter pylori or NSAIDs-induced ulcers, vascular disease causing bowel ischemia, alcohol abuse causing pancreatitis, trauma, or IBD causing bowel perforation
- PD peritonitis:
- Nonsterile technique
- Recent instrumentation
General Prevention
- SBP prophylaxis decreases mortality in patients at high risk (e.g., ascitic fluid protein concentration <1.0 g/dL, esophageal varices, or history of previous SBP).
- Antibiotics include norfloxacin, ciprofloxacin, TMP/SMZ PO, ceftriaxone IV.
- Patients with cirrhotic ascites who have low ascitic fluid protein (<1.5 g/dL), renal impairment (creatinine ≥1.2 mg/dL, BUN ≥25 mg/dL, serum sodium [Na] ≤130 mEq/L), or liver failure (Child-Pugh score ≥9 and serum bilirubin ≥3 mg/dL) should also receive SBP prophylaxis.
- Limit use of PPIs.
- PD peritonitis:
- Sterile techniques
- Antibiotic prophylaxis prior to selected procedures
Commonly Associated Conditions
SBP almost always occurs in the setting of decompensated cirrhosis.
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Citation
Domino, Frank J., et al., editors. "Peritonitis, Acute." 5-Minute Clinical Consult, 27th ed., Wolters Kluwer, 2020. Medicine Central, im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688859/all/Peritonitis_Acute.
Peritonitis, Acute. In: Domino FJF, Baldor RAR, Golding JJ, et al, eds. 5-Minute Clinical Consult. Wolters Kluwer; 2020. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688859/all/Peritonitis_Acute. Accessed November 30, 2023.
Peritonitis, Acute. (2020). In Domino, F. J., Baldor, R. A., Golding, J., & Stephens, M. B. (Eds.), 5-Minute Clinical Consult (27th ed.). Wolters Kluwer. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688859/all/Peritonitis_Acute
Peritonitis, Acute [Internet]. In: Domino FJF, Baldor RAR, Golding JJ, Stephens MBM, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2020. [cited 2023 November 30]. Available from: https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688859/all/Peritonitis_Acute.
* Article titles in AMA citation format should be in sentence-case
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