Signs and Symptoms of Spontaneous Bacterial Peritonitis
Perform diagnostic paracentesis immediately in any cirrhotic patient with ascites who is hospitalized emergently, regardless of symptoms, because up to one-third of SBP patients are completely asymptomatic or present only with non-abdominal manifestations like encephalopathy or acute kidney injury. 1, 2
Classic Abdominal Manifestations
The typical peritoneal findings occur in 74-95% of cases but are notably absent in a substantial minority: 2, 3
- Abdominal pain and tenderness with or without rebound tenderness 1, 2
- Guarding and abdominal rigidity (present in 82.5% when symptomatic) 3
- Ileus with decreased bowel sounds 1, 3
- Nausea and vomiting (35% of cases) 3
Systemic Signs of Infection
Fever and systemic inflammatory markers are inconsistently present: 1, 3
- Fever >38.5°C occurs in only 38% of cases 3
- Hypothermia or chills may occur instead of fever 1
- Tachycardia (62.5% of patients) 3
- Hypotension indicating progression to septic shock 3
Non-Specific Presentations (Critical Pitfall)
The most dangerous clinical scenario is the asymptomatic or minimally symptomatic patient—up to one-third present without any abdominal symptoms. 1, 2, 4 These patients may only demonstrate:
- Hepatic encephalopathy as the sole manifestation 1, 2, 3
- Acute kidney injury without other symptoms 1, 2
- Unexplained clinical deterioration or worsening jaundice 1
Laboratory Abnormalities
While not symptoms per se, these findings accompany the clinical presentation: 3
- Leukocytosis with left shift (only 40% of cases) 3
- Elevated C-reactive protein 3
- Increased serum lactate 3
- Rising creatinine (>50% above baseline) 3
Time-Critical Considerations
In patients with septic shock from SBP, mortality increases by 10% for every hour's delay in initiating antibiotics. 2, 4 This makes the absence of symptoms particularly dangerous, as it delays recognition and treatment. 1
Mandatory Diagnostic Approach
The American Association for the Study of Liver Diseases mandates diagnostic paracentesis in the following scenarios, independent of symptom presence: 1, 4
- Any cirrhotic patient with ascites admitted emergently for any reason 1, 4
- Any hospitalized or outpatient cirrhotic with signs suggestive of infection 1
- Patients with tense ascites and acute kidney injury to exclude SBP as the cause 1
- Cirrhotic patients with upper gastrointestinal bleeding 5
The diagnosis is confirmed by ascitic fluid absolute neutrophil count >250 cells/mm³, not by clinical symptoms alone. 1, 4, 5