What are the signs of peritonitis?

Signs of Peritonitis in Cirrhotic Patients

In patients with cirrhosis and ascites, peritonitis presents with abdominal pain and tenderness (occurring in 74-95% of cases), often accompanied by rebound tenderness and guarding, though up to one-third of patients may be entirely asymptomatic or present only with encephalopathy and/or acute kidney injury. 1, 2

Local Abdominal Signs

• Abdominal pain and tenderness are the most common findings, present in 74-95% of patients, and when present, strongly suggest spontaneous bacterial peritonitis (SBP) 2, 3
• Abdominal rigidity is a key clinical feature that strongly suggests peritonitis 2, 4
• Rebound tenderness and guarding frequently accompany the pain and tenderness 2, 4
• Abdominal distension is commonly observed, with isolated distension seen in 6.6% of patients 2, 4
• Decreased bowel sounds or ileus symptoms (vomiting, absence of defecation) may be present 1, 2, 4

Systemic Signs of Inflammation

• Fever or hypothermia - fever >38.5°C occurs in approximately 38% of patients, though absence of fever does not exclude infection 1, 2
• Tachycardia is observed in 62.5% of patients (not bradycardia) 2, 4
• Chills and altered white blood cell count are common systemic inflammatory signs 1
• Tachypnea may be present as part of the systemic inflammatory response 4

Signs of Clinical Deterioration

• Worsening hepatic encephalopathy is a critical sign that should raise suspicion for SBP even without abdominal symptoms 1, 4
• Acute kidney injury with increased creatinine (>50% above baseline) or decreased urinary output (oliguria) 1, 4
• Worsening liver function with jaundice 1
• Hemodynamic instability or shock with hypotension and signs of hypoperfusion (lactic acidosis, altered mental status) 1, 2, 4
• Gastrointestinal bleeding may occur in 15% of patients 2

Laboratory Findings Suggesting Peritonitis

• Leukocytosis with left shift (band neutrophils >20%) is common, though leukocytosis occurs in only 40% of patients 2, 4
• Elevated C-reactive protein (CRP) levels 2, 4
• Elevated serum lactate suggesting tissue hypoperfusion 2, 4
• Ascitic fluid neutrophil count >250/mm³ is diagnostic for SBP 1, 2

Critical Clinical Pitfalls

Physician clinical impression alone is insufficient to exclude SBP - studies show that clinical assessment has only 76% sensitivity and 34% specificity, with 4.2% of SBP patients assessed as "little to no risk" by physicians, three of whom subsequently died 5. This is why diagnostic paracentesis must be performed in all hospitalized cirrhotic patients with ascites, regardless of symptoms 1.

Up to one-third of patients with SBP may be completely asymptomatic or present only with encephalopathy or AKI without any abdominal signs 1. The absence of classic peritoneal signs does not rule out infection 5, 3.

Distinguishing Primary from Secondary Peritonitis

Secondary bacterial peritonitis should be suspected when:

• Localized abdominal symptoms or signs are present 1
• Multiple organisms are found on ascitic culture 1, 6
• Very high ascitic neutrophil count is present 1
• High ascitic protein concentration (>1 g/dL), elevated LDH, or low glucose (<50 mg/dL) 2, 6
• Inadequate response to appropriate antibiotic therapy or persistence of symptoms despite improvement in ascitic fluid analysis 1, 6

In such cases, prompt CT scanning and early surgical consultation are essential 1, 6, as secondary peritonitis requires source control procedures in addition to antibiotics 2.

Immediate Action Required

Any patient with cirrhosis and ascites who develops fever, abdominal symptoms, encephalopathy, AKI, or clinical deterioration requires immediate diagnostic paracentesis before any delay 1. In your patient's case with rapid weight loss, AKI risk, and GFR of 25, any signs of infection warrant urgent evaluation as mortality increases by 10% for every hour's delay in initiating antibiotics in septic patients 1.