A 45-year-old woman from rural Odisha presents with a 2-month history of right upper quadrant pain, fever, and hepatomegaly. Ultrasound shows a 6 cm hypoechoic lesion in the right lobe of the liver with a 'double target sign'. Serology is positive for *E. histolytica* IgG antibodies. Stool examination is negative for cysts. What is the most appropriate next step in management?

## Diagnosis: Amoebic Liver Abscess (ALA) ### Clinical Presentation The patient has classic features of amoebic liver abscess: - Right upper quadrant pain (right lobe involvement is most common) - Fever - Hepatomegaly - Imaging: hypoechoic lesion with 'double target sign' (pathognomonic) - Positive serology (IgG antibodies indicate invasive disease) - **Negative stool examination** (cysts absent in 75% of ALA cases) ### Why Medical Management is First-Line **High-Yield:** Uncomplicated amoebic liver abscess (ALA) is treated **medically** in >90% of cases. Percutaneous or surgical drainage is reserved for specific complications. ### Treatment Algorithm ```mermaid flowchart TD A["Amoebic Liver Abscess"]:::outcome --> B{"Uncomplicated?"}:::decision B -->|"Yes"| C["Metronidazole 750 mg TDS × 10 days"]:::action C --> D["Then Paromomycin 25-35 mg/kg/day × 7 days"]:::action D --> E["Follow-up imaging at 3-6 months"]:::action B -->|"No (rupture, secondary infection)"| F["Percutaneous/Surgical Drainage"]:::urgent F --> G["+ Metronidazole + Paromomycin"]:::action ``` ### Two-Drug Regimen Rationale **Key Point:** ALA requires **both** tissue and luminal amoebicides: | Drug | Class | Purpose | Dosing | |------|-------|---------|--------| | Metronidazole | Tissue amoebicide | Kills trophozoites in liver abscess | 750 mg TDS × 10 days | | Paromomycin | Luminal amoebicide | Eliminates intestinal cysts; prevents relapse | 25–35 mg/kg/day × 7 days | **Clinical Pearl:** Metronidazole alone is insufficient because it does not reliably eliminate luminal cysts. Relapse occurs in 10–15% of cases if luminal amoebicide is omitted. ### Why Percutaneous Drainage is NOT First-Line **Warning:** Percutaneous or surgical drainage is indicated ONLY in: 1. **Rupture** (into peritoneum, pleura, or pericardium) 2. **Secondary bacterial infection** (fever unresponsive to antibiotics, positive culture) 3. **Large abscess** (>10 cm) with risk of rupture 4. **Left lobe abscess** (risk of rupture into pericardium) 5. **Failure to improve** after 5–7 days of medical therapy This patient has an uncomplicated 6 cm right lobe abscess — medical therapy is appropriate. ### Why Chloroquine Monotherapy is Wrong **High-Yield:** Chloroquine is an **older agent** rarely used now. It: - Has slower onset than metronidazole - Does NOT eliminate luminal cysts - Is inferior for tissue penetration - Is no longer recommended in current guidelines ### Prognosis with Medical Management - Clinical improvement: 3–5 days - Abscess resolution: 3–6 months (imaging may lag clinical recovery) - Cure rate: >90% with compliant medical therapy [cite:Harrison 21e Ch 229; Park 26e Ch 8]