What are the types of hepatic (liver) failure?

Types of Hepatic Failure

Hepatic failure is classified into three main types based on the underlying disease: Type A (acute liver failure), Type B (portosystemic bypass/shunting), and Type C (cirrhosis-related). 1

Classification of Hepatic Failure

1. Based on Underlying Disease

• Type A: Acute liver failure (ALF) - occurs in patients without pre-existing liver disease, characterized by rapid onset of hepatic dysfunction, coagulopathy, and encephalopathy 1

  • Distinct features include risk of increased intracranial pressure and cerebral herniation 1
  • Common causes include paracetamol toxicity, viral hepatitis, drug-induced liver injury, and ischemic liver injury 2, 3

• Type B: Failure resulting predominantly from portosystemic bypass or shunting 1

  • Clinical manifestations similar to Type C 1
  • Often related to surgical shunts or spontaneous portosystemic collaterals 1

• Type C: Failure resulting from cirrhosis 1

  • Most common form of hepatic failure 1
  • Represents decompensation of pre-existing chronic liver disease 1

2. Based on Severity of Manifestations

Hepatic encephalopathy (HE) severity is graded as follows 1:

• Grade I: Shortened attention span, altered sleep rhythm, lethargy, mild disorientation for time 1
• Grade II: Inappropriate behavior, somnolence, disorientation for space, asterixis 1
• Grade III: Confusion, gross disorientation, bizarre behavior 1
• Grade IV: Coma, no response to painful stimuli 1

3. Based on Time Course

• Episodic HE: Isolated episodes of hepatic encephalopathy 1
• Recurrent HE: Episodes occurring with time intervals of 6 months or less 1
• Persistent HE: Continuous behavioral alterations interspersed with relapses of overt HE 1

4. Based on Precipitating Factors

• Nonprecipitated: No identifiable trigger 1
• Precipitated: With identifiable triggers that should be specified 1
  • Common precipitants include infection, bleeding, constipation, electrolyte disorders, and medications 1

Emerging Classification: Acute-on-Chronic Liver Failure (ACLF)

• ACLF: A severe form of acutely decompensated cirrhosis characterized by organ system failure(s) and high short-term mortality (≥20% at 28 days) 1
• Distinguished by excessive systemic inflammatory response triggered by clinical precipitants (e.g., infection with sepsis, severe alcohol-related hepatitis) 1
• Requires urgent stabilization and consideration for liver transplantation 1

Diagnostic Considerations

Differential Diagnosis of Hepatic Encephalopathy

• Metabolic disorders: Diabetic conditions (hypoglycemia, ketoacidosis), electrolyte disorders (hyponatremia, hypercalcemia) 1
• Substance-related: Alcohol (intoxication, withdrawal, Wernicke's encephalopathy), drugs (benzodiazepines, neuroleptics, opioids) 1
• Neurological: Neuroinfections, nonconvulsive epilepsy, intracranial bleeding, stroke 1
• Other: Psychiatric disorders, severe medical stress (organ failure, inflammation) 1

Special Clinical Presentations

• Hepatic myelopathy: Characterized by severe motor abnormalities with relatively mild mental dysfunction, often related to long-standing portocaval shunting 1
• Cirrhosis-associated parkinsonism: Presents with extrapyramidal signs, unresponsive to ammonia-lowering therapy, occurs in approximately 4% of advanced liver disease cases 1

Management Considerations

Acute Liver Failure (Type A)

• Early transfer to an intensive care unit in a center with liver transplant capability is recommended 4
• Evaluation for urgent liver transplantation in specific conditions like Wilson's disease 4
• King's College criteria used to determine transplant candidacy 4

Acute-on-Chronic Liver Failure

• Requires classification according to the ACLF grading system based on number of organ failures 4
• Early identification and treatment of precipitating factors is crucial 4
• Patients with ACLF grade 2-3 should be considered for liver transplantation 4

Clinical Pitfalls and Caveats

• HE is often considered fully reversible, but research suggests that repeated episodes may lead to persistent cognitive deficits 1
• Isolated hyperbilirubinemia may be due to Gilbert's syndrome or hemolysis rather than worsening liver function 4
• In ischemic hepatitis, serum bilirubin is usually <3 mg/dL despite marked elevations in transaminases and coagulopathy 4
• A thorough diagnostic workup is required to exclude other disorders that can mimic hepatic encephalopathy 1