What are the criteria for diagnosing liver failure in pediatric patients?

Pediatric Acute Liver Failure Diagnostic Criteria

Pediatric acute liver failure (PALF) is diagnosed when a child without known chronic liver disease presents with liver-based coagulopathy unresponsive to parenteral vitamin K, plus either an INR of 1.5-1.9 with clinical encephalopathy OR an INR ≥2.0 regardless of encephalopathy status. 1

Core Diagnostic Criteria

The three essential entry criteria that must ALL be present are: 1

• Absence of known chronic liver disease - This distinguishes acute from acute-on-chronic liver failure 1
• Liver-based coagulopathy not correcting with vitamin K - Administer parenteral vitamin K and reassess; persistent coagulopathy confirms hepatocellular dysfunction 1
• INR threshold with or without encephalopathy:
  • INR 1.5-1.9 requires clinical evidence of encephalopathy 1
  • INR ≥2.0 qualifies regardless of encephalopathy presence 1

Clinical Manifestations Supporting the Diagnosis

Coagulation Abnormalities

• Uncorrectable coagulopathy despite vitamin K administration indicates severe hepatocellular dysfunction 1, 2
• Bleeding manifestations including gastrointestinal bleeding, umbilical stump bleeding, easy bruising, or CNS hemorrhage 2
• Prolonged PT/INR reflecting impaired synthesis of vitamin K-dependent clotting factors (II, VII, IX, X) and factor V 2

Hepatic Encephalopathy

• Ranges from subtle behavioral changes to coma, though may be subclinical in neonates 2
• Advancing encephalopathy indicates deteriorating hepatic function requiring urgent transplant evaluation 2

Metabolic Derangements

• Hypoglycemia from impaired gluconeogenesis and glycogen storage 3
• Metabolic acidosis reflecting impaired hepatic detoxification 3
• Elevated ammonia levels contributing to encephalopathy 3

Cholestatic Features

• Jaundice with elevated conjugated bilirubin distinguishing hepatocellular from hemolytic causes 2
• Elevated serum transaminases (ALT, AST) indicating hepatocellular injury 2

Synthetic Dysfunction

• Hypoalbuminemia from decreased hepatic synthesis, contributing to ascites and edema 2

Critical Management Principle

Immediate contact with a pediatric liver transplant center is mandatory upon diagnosis, as clinical deterioration can occur rapidly and unexpectedly. 1 Children with PALF may experience rapid death, and coordinated multidisciplinary care involving pediatric gastroenterology, intensive care, and transplant surgery optimizes outcomes 1, 4, 5

Age-Specific Diagnostic Considerations

Diagnoses differ between infants, children, and adolescents, with some potentially treatable causes including: 1

• Herpes simplex virus infection
• Gestational alloimmune liver disease
• Autoimmune hepatitis
• Wilson's disease

Establish an etiology to identify conditions treatable without transplantation or contraindicated for transplantation. 1 However, children with indeterminate diagnosis are more likely to require liver transplantation 1

Common Pitfall

Do not wait for encephalopathy to develop if INR ≥2.0 - this threshold alone meets PALF criteria and warrants immediate transplant center contact 1. The absence of encephalopathy does not exclude the diagnosis when coagulopathy is severe enough.