A 42-year-old woman with cirrhosis (Child-Pugh C) presents with fever (38.8°C), abdominal pain, and altered mental status. On examination, she is hypotensive (BP 82/48 mmHg), tachycardic (HR 126/min), and has diffuse abdominal tenderness without guarding. Ascitic fluid analysis shows: WBC 350/μL (neutrophils 80%), protein 1.2 g/dL, glucose 45 mg/dL, and culture is pending. Serum creatinine is 2.8 mg/dL (baseline 1.2), and lactate is 5.1 mmol/L. Which of the following is the most appropriate next step in management?

Explanation

## Spontaneous Bacterial Peritonitis (SBP) with Septic Shock **Key Point:** This patient has spontaneous bacterial peritonitis (SBP) complicated by septic shock. Ascitic fluid WBC >250/μL with neutrophil predominance (80%) + positive culture/symptoms = SBP. The combination of hypotension, elevated lactate, and renal dysfunction indicates septic shock requiring urgent intervention. **High-Yield:** SBP management in septic shock requires a **triple-pronged approach**: 1. **Empirical antibiotics** — within 1 hour (cefotaxime or fluoroquinolone) 2. **Albumin infusion** — reduces renal failure and mortality (specific to SBP, not general sepsis) 3. **Vasopressor support** — terlipressin (splanchnic vasoconstrictor) preferred over noradrenaline in cirrhotic shock ### Pathophysiology of SBP-Induced Septic Shock - **Bacterial translocation** — impaired gut barrier in cirrhosis → spontaneous infection of ascites - **Splanchnic vasodilation** — portal hypertension + endotoxemia → severe hypotension - **Renal vasoconstriction** — hepatorenal reflex → acute kidney injury (creatinine 2.8) - **Albumin depletion** — cirrhotic patients have low oncotic pressure; albumin infusion restores plasma volume and renal perfusion ### SBP Diagnostic Criteria | Criterion | Value | Interpretation | |-----------|-------|----------------| | Ascitic fluid WBC | >250/μL | Suggests bacterial infection | | Neutrophil % | >50% | Supports SBP (vs. TB or malignancy) | | Glucose | <50 mg/dL | Poor prognostic marker; suggests virulent organism | | Protein | <1.5 g/dL | Risk factor for SBP | | Culture positive | Yes/No | Confirms diagnosis but not required for treatment | **Clinical Pearl:** Do NOT wait for culture results to start antibiotics. Mortality increases by ~4% per hour of antibiotic delay in SBP-septic shock. ### Why Albumin is Essential in SBP (Not General Sepsis) ```mermaid flowchart TD A[SBP + Septic Shock in Cirrhosis]:::outcome --> B[Albumin infusion]:::action B --> C[Restores plasma oncotic pressure]:::action C --> D[Improves renal perfusion]:::action D --> E[Reduces acute kidney injury]:::action E --> F[Reduces mortality by ~30%]:::outcome A --> G[Terlipressin vasopressor]:::action G --> H[Splanchnic vasoconstriction]:::action H --> I[Improves systemic hemodynamics]:::action I --> J[Reduces renal failure risk]:::outcome ``` **Mnemonic:** **SBP-CARE** — Start antibiotics, Broad-spectrum (cefotaxime), Paracentesis (diagnostic), Albumin, Renal protection (terlipressin), Early intervention. ### Albumin Dosing in SBP - **At diagnosis:** 1.5 g/kg IV - **Day 3:** 1.0 g/kg IV - **Reduces renal failure from 33% → 10%** and mortality from 29% → 10% [cite:Harrison 21e Ch 297] ### Vasopressor Choice in Cirrhotic Shock | Vasopressor | Mechanism | Use in SBP | |-------------|-----------|------------| | **Terlipressin** | Vasopressin analog; splanchnic + systemic vasoconstriction | **Preferred** — improves renal perfusion | | **Noradrenaline** | α + β; systemic vasoconstriction | Second-line if terlipressin unavailable | | **Dopamine** | Low-dose: renal; high-dose: systemic | Avoid — increases arrhythmias | **Warning:** Diuretics (furosemide) are contraindicated in SBP-septic shock; they worsen renal perfusion and precipitate hepatorenal syndrome.