## Management of Amoebic Liver Abscess (ALA) ### Clinical Diagnosis **Key Point:** The combination of RUQ pain, fever, hepatomegaly, hypoechoic liver lesion on ultrasound, and positive serology for *E. histolytica* antibodies confirms amoebic liver abscess. Negative stool microscopy does NOT exclude ALA — only 10% of ALA patients have concurrent intestinal infection with detectable cysts. ### Diagnostic Criteria for ALA | Criterion | Finding | |-----------|----------| | **Clinical** | RUQ pain, fever, hepatomegaly | | **Imaging** | Hypoechoic/anechoic lesion on ultrasound or CT | | **Serology** | Anti-*E. histolytica* IgG positive (>90% sensitive in ALA) | | **Stool** | May be negative (cysts not always present) | | **Aspiration** | Sterile, anchovy-paste material; culture negative | **High-Yield:** Positive serology + imaging + clinical features = ALA diagnosis. Aspiration is NOT needed for diagnosis in uncomplicated cases. ### Treatment Algorithm ```mermaid flowchart TD A[Amoebic Liver Abscess confirmed]:::outcome --> B{Uncomplicated ALA?}:::decision B -->|Yes| C[Metronidazole 750 mg TDS × 10 days]:::action C --> D[Paromomycin 25-35 mg/kg/day × 7 days]:::action D --> E[Clinical response in 3-5 days]:::outcome B -->|No - Rupture/Peritonitis| F[Urgent surgical drainage]:::urgent B -->|No - Large/symptomatic| G[Consider percutaneous drainage + medical therapy]:::action ``` ### Rationale for Metronidazole + Paromomycin 1. **Metronidazole (tissue amebicide):** - Penetrates liver abscess wall and kills trophozoites - Dose: 750 mg TDS × 10 days (or 800 mg TDS) - Cure rate: >90% for uncomplicated ALA - Response: fever resolves in 3–5 days; abscess shrinks over weeks 2. **Paromomycin (luminal agent):** - Eliminates intestinal cysts to prevent relapse and transmission - Dose: 25–35 mg/kg/day in 3 divided doses × 7 days - Must follow tissue amebicide (not simultaneous) **Clinical Pearl:** Aspiration is reserved for: - Diagnostic uncertainty (e.g., to exclude pyogenic abscess) - Large abscesses (>5 cm) with risk of rupture - Failure to respond to medical therapy after 5–7 days - Abscesses in left lobe (risk of pericardial rupture) ### Why NOT Aspiration First? - **Sterile culture:** Amoebic abscess contains no bacteria; culture is negative - **Risk of rupture:** Needle aspiration may perforate the abscess - **Diagnosis already confirmed:** Serology + imaging is sufficient - **Medical therapy effective:** >90% cure without drainage in uncomplicated cases ### Why NOT Chloroquine? **Warning:** Chloroquine is used for *extraintestinal* amoebiasis in some older regimens, but it is NOT first-line for ALA. Metronidazole is superior and is the standard of care globally. **Mnemonic:** **METRO-PARA-DRAIN** — Metro for tissue, Para for lumen, DRAIN only if medical failure or rupture risk.
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