From the Guidelines
Yes, a patient can have Spontaneous Bacterial Peritonitis (SBP) even if there is not enough ascites for a paracentesis, though this scenario presents a diagnostic challenge. When ascites is minimal, clinicians should rely on clinical signs and symptoms such as fever, abdominal pain, altered mental status, or worsening liver function to suspect SBP, as recommended by the guidelines on the management of ascites in cirrhosis 1. In these cases, empiric antibiotic treatment may be warranted without diagnostic confirmation. The typical regimen includes a third-generation cephalosporin like ceftriaxone 1-2g IV daily for 5-7 days, or alternatives such as ciprofloxacin 400mg IV twice daily or levofloxacin 750mg IV daily for patients with penicillin allergies.
According to the 2021 practice guidance by the American Association for the Study of Liver Diseases 1, a diagnostic paracentesis should be performed as soon as a patient with cirrhosis and ascites is hospitalized emergently for any reason, even in the absence of symptoms suggestive of infection. If pleural effusion is present, a diagnostic thoracentesis should be performed when there is no ascites or when diagnostic paracentesis has ruled out SBP while bacterial infection is suspected.
SBP can develop in small-volume ascites because the pathophysiology involves bacterial translocation from the gut into the peritoneal fluid, combined with impaired immune function in cirrhotic patients. The reduced ascitic fluid volume doesn't prevent infection but makes diagnosis more difficult. In patients with cirrhosis who show signs of infection without an obvious source, clinicians should maintain a high suspicion for SBP and consider empiric treatment while pursuing other diagnostic approaches.
Key points to consider in the diagnosis and management of SBP include:
- Clinical signs and symptoms such as fever, abdominal pain, altered mental status, or worsening liver function should raise suspicion for SBP 1
- Empiric antibiotic treatment may be warranted without diagnostic confirmation in cases where ascites is minimal 1
- Ascitic fluid culture is essential in the evaluation of SBP and should be performed before the administration of the first dose of antibiotics 1
- Bedside inoculation of at least 10 mL of the ascitic sample into blood culture bottles increases the sensitivity of the culture to >90% in the diagnosis of SBP 1
From the Research
Spontaneous Bacterial Peritonitis (SBP) Diagnosis
- SBP is a common complication in patients with liver cirrhosis, with an increased risk of mortality 2.
- Diagnostic paracentesis should be performed in all patients with ascites and clinical features with high diagnostic suspicion 2, 3.
- The final diagnosis requires the analysis of ascites and the presence of > 250 mm3 neutrophil polymorphonuclear (PMN) in ascites 2.
Paracentesis and SBP
- Cirrhotic patients with ascites and clinical suspicion for SBP should have a diagnostic paracentesis performed prior to admission unless platelets <40,000-50,000/μL 3.
- Paracentesis is not contraindicated in patients with prolonged prothrombin time 3.
- Limited data support platelet administration prior to paracentesis if <40,000-50,000/μL 3.
SBP without Enough Ascites for Paracentesis
- There is no direct evidence to suggest that a patient cannot have SBP if there is not enough ascites for a paracentesis.
- However, the diagnosis of SBP relies heavily on the analysis of ascites, and the presence of > 250 mm3 neutrophil polymorphonuclear (PMN) in ascites is required for a definitive diagnosis 2.
- In cases where there is not enough ascites for a paracentesis, alternative diagnostic methods may be considered, but the accuracy and reliability of these methods are not well established 4.
Importance of Early Paracentesis
- Early paracentesis is essential for rapid diagnosis and optimal treatment of SBP 5.
- Delayed paracentesis is associated with increased in-hospital mortality in patients with SBP 5.
- Each hour delay in paracentesis is associated with a 3.3% increase in in-hospital mortality after adjusting for MELD score and creatinine levels 5.