⚠️ Spontaneous Bacterial Peritonitis (SBP) is a life-threatening infection of ascitic fluid. 💡 Always suspect in cirrhotic patients with ascites who develop encephalopathy, renal dysfunction, GI bleed, fever, or abdominal pain. 👉 A diagnostic paracentesis should be performed in all cases of new ascites or clinical suspicion.

📖 About

SBP = infection of ascitic fluid without an obvious intra-abdominal source.
Seen in ~8–10% of cirrhotics with ascites; recurrence is common.
Associated with high morbidity and mortality; survival improves with early detection + treatment.

⚙️ Aetiology / Pathophysiology

🔻 Cirrhosis → impaired immunity (low complement, opsonins) → ↑ infection risk.
🔄 Portosystemic shunting → reduced hepatic clearance of bacteria.
🧬 Translocation of gut bacteria across the intestinal wall → bloodstream → ascites.

🦠 Microbiology

Gram-negative: E. coli, Klebsiella (most common).
Gram-positive: Streptococcus (esp. viridans), Enterococcus, Pneumococcus.

🔎 When to Suspect SBP

GI bleeding or septic shock.
Fever, abdominal pain, vomiting, or ileus.
New/worsening hepatic encephalopathy.
Deteriorating renal or liver function (esp. ↑ creatinine).
Unexplained systemic inflammatory signs.

💡 Mnemonic – FEVER: F = Fever E = Encephalopathy V = Vomiting E = Elevated creatinine (renal dysfunction) R = Rebound tenderness

🧪 Investigations

💉 Ascitic fluid tap: Neutrophils >250/mm³ = diagnostic (start antibiotics immediately).
🧫 Culture: Inoculate ascitic fluid directly into blood culture bottles at bedside (↑ sensitivity).
📉 SAAG: Helps determine cause of ascites (not diagnostic of SBP but useful background).
📊 Bloods: FBC (↑ WCC, anaemia), U&E (renal function), LFTs (liver status), coagulation profile.
🟣 Other: pH low in infected fluid, leukocyte esterase strips may give rapid bedside clue.

💊 Management

🚨 Immediate antibiotics: Start if PMN >250/mm³. – IV Cefotaxime 2 g tds OR Ceftriaxone (check local guidelines).
💧 Albumin infusion: If renal dysfunction or bilirubin >68 μmol/L. – Day 1: 1.5 g/kg → Day 3: 1 g/kg → reduces hepatorenal syndrome.
🛡️ Prophylaxis: After an episode of SBP, prescribe norfloxacin, ciprofloxacin, or co-trimoxazole long-term to reduce recurrence risk.
💉 GI bleed prophylaxis: Patients with variceal bleeding should receive SBP prophylaxis.
🫀 Transplant referral: Any patient with SBP should be assessed early for liver transplant eligibility.

⚠️ Complications

Hepatorenal syndrome (HRS).
Sepsis and septic shock.
Recurrent SBP (up to 70% within 1 year without prophylaxis).
High short-term mortality if untreated.

📚 References

🌟 Teaching Pearl: Any cirrhotic patient with ascites + acute decompensation → do a diagnostic paracentesis before antibiotics. If neutrophils >250 → treat immediately. 💡 Mortality halves with prompt recognition + therapy.

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Spontaneous Bacterial Peritonitis