Pyogenic liver abscess

Introduction

A pyogenic liver abscess is a pus-filled collection within the liver, caused by bacterial infection. It is a medical emergency that can progress to sepsis and organ failure if not promptly treated. The infection typically arises from the biliary tract (e.g. cholangitis), portal venous system (e.g. intra-abdominal sepsis), or haematogenous spread (e.g. from endocarditis).

Peak Incidence

• Most commonly affects adults aged 40 to 60 years.

Pathophysiology

• Bacteria gain access to hepatic tissue via:
  • Ascending biliary infection – Most common route (e.g. cholangitis, gallstones).
  • Portal venous seeding – From gastrointestinal infections (e.g. diverticulitis, appendicitis).
  • Haematogenous spread – From systemic infections (e.g. endocarditis).
  • Direct extension – From adjacent infected organs.
  • Trauma or post-surgical complication.
• The local immune response forms a walled-off collection of pus, which may enlarge or rupture if not managed.

Symptoms

• Fever and rigors.
• Right upper quadrant (RUQ) pain – May be mild or severe.
• Nausea and vomiting.
• Fatigue and malaise.
• Anorexia and weight loss.
• Cough and pleuritic chest pain – If associated pleural effusion is present.

Signs

• Tender hepatomegaly.
• Jaundice – In advanced cases or biliary obstruction.
• Signs of sepsis – Tachycardia, hypotension, fever.
• Pleural effusion – Especially if the abscess extends to the diaphragm.

Diagnosis

Blood Tests

• FBC – Leukocytosis (often with neutrophilia).
• CRP and ESR – Markedly elevated.
• Liver function tests (LFTs):
  • Raised ALP, GGT, and bilirubin.
  • Hypoalbuminaemia in prolonged or severe infection.
• Blood cultures – Positive in up to 60% of cases.

Imaging

• Ultrasound (USS):
  • First-line imaging.
  • May show hypoechoic or mixed echogenic lesions.
• CT scan (with contrast):
  • Gold standard.
  • Reveals hypodense lesions with peripheral rim enhancement (“double target sign”).
• MRI:
  • Reserved for inconclusive CT/USS findings.
  • Superior in soft tissue characterisation.

Definitive Diagnosis

• Image-guided percutaneous aspiration:
  • Allows for Gram stain and culture to identify the causative organism.
  • Confirms diagnosis and guides targeted antibiotic therapy.

Complications

• Rupture into:
  • Peritoneal cavity → peritonitis.
  • Pleural space → empyema or pneumonia.
  • Retroperitoneum.
• Sepsis and septic shock.
• Chronic liver disease or abscess recurrence.
• Hepatic failure in severe or untreated cases.

Management

Antibiotic Therapy

• Empirical broad-spectrum IV antibiotics:
  • E.g. piperacillin–tazobactam, ceftriaxone + metronidazole, or meropenem.
• Tailor antibiotics based on culture and sensitivity.
• Total antibiotic course typically lasts 4–6 weeks, starting IV and switching to oral once clinically stable.

Percutaneous Drainage

• Image-guided needle aspiration or catheter drainage is often required.
• Indicated for:
  • Abscesses >3–5 cm.
  • Lack of clinical response to antibiotics within 48–72 hours.

Surgical Intervention

• Rarely needed.
• Consider open surgical drainage or liver resection for:
  • Multiloculated or inaccessible abscesses.
  • Failed percutaneous drainage.

Supportive Care

• IV fluids – To maintain haemodynamic stability.
• Analgesia – For pain control.
• Nutritional support – In prolonged illness.

Monitoring and Follow-Up

• Regular observations – For signs of sepsis resolution.

• Repeat imaging (USS or CT) – To monitor resolution.

• Serial blood tests – To track inflammatory markers, renal and liver function.