From the Guidelines
The most critical step in managing suspected peritonitis is to perform paracentesis with fluid analysis, including cell count, culture, and Gram stain, as soon as possible, as recommended by the most recent guidelines 1. When peritonitis is suspected, the following studies should be obtained on peritoneal fluid:
- Cell count with differential
- Culture (aerobic and anaerobic)
- Gram stain
- Protein and albumin levels
- LDH and glucose levels These tests help to confirm the diagnosis of peritonitis, identify the causative organism, and guide antibiotic therapy. The management of peritonitis involves a combination of antibiotic therapy and surgical intervention, if necessary.
- Antibiotic therapy should be started empirically, with coverage for both aerobic and anaerobic organisms, as soon as possible, and adjusted based on culture results 1.
- Surgical intervention is necessary for secondary peritonitis to address the underlying cause, such as perforated viscus or appendicitis. Some key points to consider in the management of peritonitis include:
- Early intervention is critical to prevent the progression to sepsis and multi-organ failure 1.
- Fluid resuscitation with crystalloids, pain management, and close monitoring of vital signs are crucial supportive measures.
- The choice of antibiotic therapy should be guided by local resistance patterns and the severity of the infection 1.
- Follow-up imaging may be needed to ensure resolution of the infection.
From the FDA Drug Label
If there are signs of infection, specimens for cultures should be obtained for the identification of the causative organism(s) so that appropriate therapy may be given The recommended diagnostic approach for suspected peritonitis includes obtaining specimens for cultures to identify the causative organism(s) and guide appropriate therapy.
- Key diagnostic tests may include:
- Gram stain
- Culture and susceptibility testing of peritoneal fluid
- Other tests as clinically indicated When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy 2.
From the Research
Diagnostic Approach for Suspected Peritonitis
The diagnostic approach for suspected peritonitis involves analyzing peritoneal fluid for signs of infection. The following studies are recommended:
- Abdominal paracentesis to collect peritoneal fluid for analysis 3
- Cell count, including polymorphonuclear (PMN) cell count, to diagnose spontaneous bacterial peritonitis (SBP) 3, 4
- Culture of peritoneal fluid to identify the causative organism 3, 5
- Gram stain of peritoneal fluid, although its utility is limited due to low sensitivity and specificity 6, 5
Interpretation of Peritoneal Fluid Analysis
The interpretation of peritoneal fluid analysis results is crucial for diagnosing peritonitis. The following criteria are recommended:
- A PMN cell count of greater than 250 cells/mm^3 is indicative of SBP 3
- A peritoneal fluid WBC count cutoff of 230/μL can improve specificity without compromising sensitivity 7
- The presence of bacteria on Gram stain or a positive culture result can confirm the diagnosis of peritonitis 3, 5
Treatment and Monitoring of Peritonitis
The treatment and monitoring of peritonitis involve:
- Empiric antibiotic therapy with a third-generation cephalosporin, pending culture results 3
- Repeating paracentesis after 48 hours of treatment to reculture the fluid and reassess the ascitic fluid neutrophil count 3
- Monitoring the patient's clinical response to treatment and adjusting the antibiotic regimen as needed 3