Question

A 7-year-old child presents with jaundice, altered sensorium, and hepatomegaly. Which investigation is essential to confirm acute liver failure?

• A. Serum bilirubin
• B. SGPT (ALT)
• C. INR
• D. Alkaline phosphatase

Hint:

PALF Diagnostic Definition Criteria:
$\bullet$ Coagulopathy with Encephalopathy $\rightarrow$ $\text{INR} \ge 1.5$ (unresponsive to Vitamin K).
$\bullet$ Coagulopathy WITHOUT Encephalopathy $\rightarrow$ $\text{INR} \ge 2.0$ (unresponsive to Vitamin K).

Answer 1

The Correct Option is C

Concept:
Pediatric Acute Liver Failure (PALF) is a rare, life-threatening multisystem syndrome characterized by rapid onset of severe hepatocellular dysfunction in a child with no recognized prior evidence of chronic liver disease.
Because liver synthetic failure manifests early with impaired production of clotting factors, measurement of coagulopathy is the cornerstone definition.
Explanation:
• The internationally accepted Pediatric Acute Liver Failure (PALF) Study Group consensus criteria define acute liver failure as:
1. Biochemical evidence of acute liver injury, AND
2. No known underlying chronic liver disease, AND
3. Hepatic-based coagulopathy unresponsive to parenteral Vitamin K defined as:
- $\text{Prothrombin Time (PT) \ge 15\text{ seconds}$ or $\text{INR} \ge 1.5$ in the presence of hepatic encephalopathy}, OR
- $\text{PT \ge 20\text{ seconds}$ or $\text{INR} \ge 2.0$ regardless of the presence or absence of encephalopathy}.

• The International Normalized Ratio (INR) Prothrombin Time reflects the hepatic synthesis of Vitamin K-dependent clotting factors (specifically Factor VII, which has the shortest half-life of $\approx 6\text{ hours}$).

• While transaminases (ALT/AST) and serum bilirubin indicate hepatocellular damage and cholestasis, they do not assess hepatic synthetic reserve and do not define acute liver failure.

• Therefore, determining the INR is mandatory and essential to confirm the diagnosis of PALF and stratify urgency for liver transplantation.
Final Answer:
Coagulation profile assessment via INR is essential to establish the diagnosis and define acute liver failure in children.