Symptoms of Spontaneous Bacterial Peritonitis
Up to one-third of patients with spontaneous bacterial peritonitis are completely asymptomatic, making diagnostic paracentesis mandatory in all hospitalized cirrhotic patients with ascites regardless of symptoms. 1, 2
Classic Abdominal Manifestations
- Abdominal pain and tenderness (with or without rebound tenderness) occur in 74–95% of symptomatic cases, making it the most common presenting symptom 2, 3
- Guarding and abdominal rigidity are present in 82.5% of symptomatic patients 2
- Ileus with decreased bowel sounds is a characteristic finding 1, 2
- Nausea and vomiting occur in 35% of cases 2
- Abdominal distension from worsening ascites may be noted 4
Systemic Signs of Infection
- Fever >38.5°C occurs in only 38% of cases—its absence does not exclude SBP 2, 4
- Hypothermia or chills may occur instead of fever 1, 2
- Tachycardia is present in 62.5% of patients 2
- Hypotension and septic shock represent severe progression 2
Non-Specific Presentations (Critical Pitfall)
The most dangerous clinical pitfall is assuming SBP requires abdominal symptoms—up to one-third of patients present with only non-abdominal manifestations. 2, 3
- Hepatic encephalopathy may be the sole presenting feature without any abdominal complaints 1, 2, 3
- Acute kidney injury (rising creatinine) can occur as an isolated finding 1, 2
- Unexplained clinical deterioration or worsening jaundice should trigger immediate paracentesis 1, 2
- Mental status changes without fever or abdominal pain are common 5
Laboratory Abnormalities
- Leukocytosis with left shift occurs in only 40% of cases—normal white blood cell count does not exclude SBP 2
- Elevated C-reactive protein and increased serum lactate may be present 2
- Rising creatinine (>50% above baseline) can signal infection 2
Time-Critical Considerations
In patients with septic shock from SBP, mortality increases by 10% for every hour's delay in initiating antibiotics. 1, 2, 3
- The American Association for the Study of Liver Diseases mandates diagnostic paracentesis in all cirrhotic patients with ascites upon hospital admission, even if completely asymptomatic, because approximately 10–30% have SBP at presentation 1, 6, 2, 7
- Bacterial infection develops in 25–65% of cirrhotic patients with gastrointestinal bleeding, requiring immediate paracentesis 1, 6
Algorithmic Approach to Suspecting SBP
Perform immediate diagnostic paracentesis if ANY of the following are present:
- Hospital admission with cirrhosis and ascites (regardless of symptoms) 1, 6, 2
- Fever, chills, or hypothermia 1, 2
- Any abdominal pain or tenderness 1, 2
- New or worsening hepatic encephalopathy 1, 2
- Acute kidney injury or rising creatinine 1, 2
- Gastrointestinal bleeding 1, 6
- Hemodynamic instability or shock 1, 6
- Unexplained clinical deterioration 1, 2
The diagnosis is confirmed by ascitic fluid polymorphonuclear count >250 cells/mm³, not by clinical symptoms alone. 6, 2