Non-viral Infections of the Liver

Non-Viral Infections of the Liver: Comprehensive Lecture Summary

Speaker: Expert Speaker | Format: Medical Education Lecture

1. Main Clinical Topics Discussed

This lecture provides a broad overview of non-viral infectious etiologies affecting the liver and biliary system, including:

• Pyogenic liver abscess
• Cholangitis
• Acute cholecystitis
• Hepatobiliary tuberculosis
• Typhoid fever (Salmonella typhi hepatic involvement)
• Additional bacterial, fungal, and parasitic hepatic infections (referenced)

2. Key Learning Points, Guidelines, and Recommendations

Pyogenic Liver Abscess

• Routes of infection: Hepatic artery, portal vein, direct abdominal extension, or trauma
• Predisposing conditions: Malignancy, hepatobiliary disease, pancreatic disease, cirrhosis, cardiopulmonary disease, diabetes
• Common organisms:

- *Enterobacteriaceae* most prevalent overall; *E. coli* and *Klebsiella* leading species

- *Klebsiella* liver abscess: associated with underlying colorectal cancer → colonoscopy referral recommended

- Polymicrobial abscesses: *Enterococcus* spp., viridans group *Streptococcus*

- *Staphylococcus aureus*: typically via hematogenous seeding post-bacteremia

- Anaerobes: associated with hepatobiliary disease or biliary instrumentation

- *Candida* spp.: most common fungal cause; hematogenous spread in oncology patients

• Diagnostic approach:

- Blood cultures (positive in up to 50% of cases)

- Ultrasound and CT as first-line imaging; MRI for biliary anatomy detail

- Aspiration mandatory for microbiologic diagnosis

• Management by size:

- <5 cm: Needle aspiration ± antibiotics

- ≥5 cm or multi-loculated: Indwelling percutaneous drain

- Refractory cases: Surgical drainage (last resort)

• Empiric antibiotics: Beta-lactam/beta-lactamase inhibitor (e.g., piperacillin-tazobactam) or 3rd/4th generation cephalosporin + metronidazole

- Carbapenem preferred in penicillin allergy

- Account for prior MDR organism colonization

• Duration: Minimum 4 weeks (small abscesses); 6+ weeks (large abscesses); guided by repeat imaging and labs

Cholangitis

• Pathophysiology: Biliary stasis → ascending infection from proximal intestine; alternate entry via lymphatic/portal systems
• Classic presentation: Charcot's triad (seen in 50–70% of patients)
• Labs: Leukocytosis; cholestatic pattern (elevated ALP, bilirubin); elevated amylase/lipase with distal bile duct obstruction
• Management:

- Empiric antibiotics (similar coverage as liver abscess)

- ERCP preferred for biliary decompression (lower morbidity than surgery); provides definitive treatment and tissue sampling

- Percutaneous drainage for patients too unstable for ERCP

Acute Cholecystitis

• Mechanism: Cystic duct obstruction → increased luminal pressure → ischemia → inflammation → secondary bacterial infection in 20–50% of cases
• Characteristic finding: Murphy's sign
• Imaging: Ultrasound (first-line); HIDA scan if diagnosis remains unclear (non-visualization of gallbladder = cystic duct obstruction)
• Management: Empiric antibiotics; elective cholecystectomy once patient stabilizes

- Urgent surgery indicated for suspected gangrene or perforation

- Percutaneous cholecystostomy or ERCP for high surgical-risk patients

Hepatic Tuberculosis

• Three forms of hepatic involvement:

1. Miliary/disseminated TB: Diffuse hepatic involvement (most common)

2. Granulomatous hepatitis: C