Liver Abscess | Medical Science Optional Notes for UPSC PDF Download

Liver Abscess-Etiology

• Pyogenic Liver Abscess (80% of cases):
  • Predominantly caused by polymicrobial infections, with E. coli being the most common causative organism.
  • K. pneumoniae is the second most common pathogen.
  • Other bacteria contributing to the infection include Enterococci, Streptococci, Staphylococcus aureus, Proteus vulgaris, and anaerobes.
• Non-Pyogenic Liver Abscess:
• Fungal Infection (<10% of cases): Candida species are the predominant causative agents.
• Amebic Liver Abscess (<10% of cases): Entamoeba histolytica is the primary organism responsible for the infection.

Liver abscess-Clinical presentation

• Classic Triad of Pyogenic Liver Abscess:
  • Fever (with or without chills and rigors).
  • Malaise.
  • Right upper quadrant pain.
• Other Symptoms:
  • Anorexia and weight loss.
  • Nausea and vomiting.
  • Symptoms of diaphragmatic irritation.
• Physical Examination:
  • Jaundice.
  • Tender hepatomegaly.
  • Intercostal tenderness.
  • Epigastric tenderness.
  • Decreased breath sounds in the right lower lobe of the lung.
  • Features of sepsis.
• Note: The symptoms of pyogenic liver abscess are often non-specific, including fever, weight loss, and others.

Liver abscess-investigations

Laboratory Tests

• Complete Blood Count:
  • Neutrophilic leukocytosis.
  • Normocytic normochromic anemia.
• Liver Function Tests and Enzymes:
  • Increased alkaline phosphatase (90%).
  • Elevated AST and ALT.
  • Hypoalbuminemia.
  • Hyperbilirubinemia.
• Inflammatory Markers:
  • Increased ESR and CRP.
• Blood Culture:
  • Positive in approximately 50% of cases.

Imaging

• Abdominal imaging is confirmatory for pyogenic liver abscess.
• Abdominal Ultrasound (US):
  • Solitary/multiple, poorly demarcated, fluid-filled, round hypoechoic lesion(s) within the hepatic parenchyma with surrounding edema and hyperemia.
• Abdominal CT Scan:
  • Similar findings to abdominal ultrasound; peripheral rim enhancement is observed with IV contrast administration.

Percutaneous Aspiration and Culture of the Aspirate

• Both diagnostic and therapeutic (refer to the "Treatment" section below).
• Performed under US or CT guidance.
• Aspirated material is cultured to determine the organism and its antibiotic-susceptibility profile.

Liver abscess-Differential diagnosis

Pyogenic Liver Abscesses Need Differentiation from Other Space-Occupying Lesions of the Liver:

• Amebic Liver Abscess: Amebic liver abscess is one of the conditions requiring differentiation.
• Hepatic Echinococcosis (Hydatid Cyst of the Liver): Hepatic echinococcosis, specifically hydatid cysts of the liver, is another entity that needs to be distinguished.
• Hepatic Cysts: Simple hepatic cysts should be considered in the differential diagnosis.
• Benign Liver Tumors: Various benign liver tumors may present as space-occupying lesions and need to be differentiated.
• Hepatocellular Carcinoma: Hepatocellular carcinoma is a malignant liver tumor that requires consideration in the differential diagnosis.
• Liver Metastases: Metastatic lesions in the liver, originating from other primary sites, should also be distinguished from pyogenic liver abscesses.

Liver abscess-Treatment

• Treatment Approach for Pyogenic Liver Abscesses: Pyogenic liver abscesses are typically managed with a combination of intravenous (IV) antibiotics and percutaneous drainage. Surgical drainage may be necessary in some cases.
• Antibiotics:
  • Antibiotics are recommended for all cases.
  • Broad-spectrum IV antibiotics include ampicillin + sulbactam, piperacillin + tazobactam, or a 3rd generation cephalosporin + metronidazole until antibiotic susceptibility is known.
• Drainage of the Abscess Cavity:
  • Percutaneous drainage or needle aspiration is indicated for nearly all pyogenic liver abscess cases.
  • For solitary abscess:
    • Small abscesses (<5 cm) may be managed with percutaneous needle aspiration.
    • Large abscesses (>5 cm) may require percutaneous drainage with intracavitary catheter placement.
    • If percutaneous drainage/aspiration is unsuccessful, a second attempt can be made before considering surgical drainage.
• Indications for Surgical Drainage (Open/Laparoscopic):
  • Multiple or loculated abscesses.
  • Deep-seated abscess not amenable to percutaneous drainage.
  • Ruptured abscess.
  • Thick viscous pus that cannot be drained percutaneously.
  • Underlying diseases requiring surgical intervention (e.g., choledocholithiasis, appendicitis, etc.).
• Contraindications: Coagulopathy (e.g., international normalized ratio (INR) > 1.5; thrombocytopenia due to sepsis).
• Considerations: The underlying etiology (e.g., choledocholithiasis, biliary stricture) should be addressed to prevent recurrent pyogenic liver abscesses.

Liver abscess-Complications

Complications of Liver Abscess:

• Rupture: Rupture can lead to various complications.
• Into the Abdomen (Peritonitis): Rupture into the abdomen can result in peritonitis.
• Into the Chest (Empyema): Rupture into the chest may lead to empyema.
• Into the Retroperitoneum (Retroperitoneal Abscess): Rupture into the retroperitoneum can cause the formation of a retroperitoneal abscess.
• Sepsis: Systemic infection (sepsis) is a potential complication.
• Pneumonia: Pneumonia can occur as a consequence.
• Pleural Effusion: Pleural effusion is another possible complication.

Poor Prognostic Factors:

• Certain factors indicate a less favorable prognosis.
• Pyogenic Abscess with Sepsis: Presence of sepsis in pyogenic abscess.
• Advanced Age (>70 Years): Older age, specifically over 70 years.
• Multiple Abscesses: The presence of multiple abscesses.
• Polymicrobial Infection; Anaerobic Infection: Infection involving multiple organisms or anaerobic bacteria.
• Immunosuppression (e.g., Malignancy, Diabetes): Weakened immune system due to conditions like malignancy or diabetes.
• Need for Surgical Drainage: The necessity for surgical drainage is also considered a poor prognostic factor.

Pathogenesis of Amoebic liver abscess

Clinical features of Amoebic liver abscess

Intestinal Amebiasis (Dysentery):

• Loose stools with mucus and bright red blood.
• Symptoms include painful defecation, tenesmus, abdominal pain, cramps, weight loss, and anorexia.
• Fever occurs in 10-30% of cases, with possible systemic symptoms like fatigue.
• High risk of recurrence, often through self-inoculation (hand to mouth).
• A chronic form resembling inflammatory bowel disease is also possible.

Extraintestinal Amebiasis:

• Symptoms typically have an acute onset; subacute courses are rare.
• In 95% of cases, manifests as amebic liver abscess, usually a solitary abscess in the right lobe.
• Fever is present in 85-90% of cases (compared to amebic dysentery).
• Right upper quadrant pain or pressure sensation is common.
• Chest pain and pleuralgia may also occur.
• Diarrhea precedes only about a third of all cases of amebic liver abscess.
• In 5% of cases, abscesses may occur in other organs, especially the lungs, and in rare cases, the brain, with accompanying organ-specific symptoms.
• Diarrhea precedes only about a third of all cases of amebic liver abscess.

Management of Amoebic liver abscess

• Diagnosis:
  • Liver function tests may exhibit mild abnormalities, with uncommon occurrences of hyperbilirubinemia.
  • CT scans, more than ultrasounds, are the primary investigative tools.
  • Confirmation of diagnosis involves serological tests (enzyme immunoassay) for antiamoebic antibodies.
  • Cultures of amoebic abscesses usually yield negative results.
• Treatment:
  • Invasive amebiasis is addressed with a nitroimidazole such as metronidazole or tinidazole, followed by a luminal amebicide like paromomycin.
  • Indications for percutaneous aspiration in amebic liver abscess include:
  • Large abscesses (>5 cm).
  • Lack of response to medical therapy within 5 days.
  • Suspected superinfection.
  • Abscesses of the left lobe of the liver at risk for rupture into the pericardium.
• Malecot Catheter:
  • Utilized in draining amoebic liver abscesses.
  • It is a self-retaining urinary catheter with an umbrella or flower tip.
  • The catheter contains sulfur, making it radioopaque.

Pyogenic vs amoebic liver abscess

Liver abscess-Repeats

Q1: What is an abscess? Describe the method of draining a deep abscess by Hilton's method. (1995)

Q2: Describe the clinical features of amoebic abscess liver and its management. (1995)

Q3: Discuss pathogenesis and lab diagnosis of amoebic liver abscess. (1998) 

Q4: What are the causes of liver abscess? Discuss their clinical presentation. How will you investigate and manage? (2006)

Q5: Enumerate the complications of liver abscess. How would you manage a 40-year old diabetic with suspected liver abscess in left lobe of liver? (2011)

Q6: What are the mode of infection, clinical presentation and complications of amoebic liver abscess? Briefly outline the management of patients with amoebic liver abscess including surgical intervention. (2013)