Question

A 10-year-old boy presents with severe abdominal pain radiating to the back, vomiting, and elevated transaminases. Which investigation will be most specific in confirming acute pancreatitis?

• A. Serum amylase
• B. Serum lipase
• C. Abdominal ultrasound
• D. CT abdomen

Hint:

Lipase vs Amylase in Pancreatitis:
$\bullet$ Serum Lipase: $>3\times$ ULN $\rightarrow$ Higher specificity, higher sensitivity, stays elevated longer ($8\text{--}14\text{ days}$). Investigation of choice!
$\bullet$ Serum Amylase: Shorter half-life ($2\text{--}3\text{ days}$), non-specific (salivary origin).

Answer 1

The Correct Option is B

Concept:
Acute pancreatitis is an acute inflammatory condition of the pancreas.
According to the International Study Group of Pediatric Pancreatitis: In Search for a Cure (INSPPIRE) criteria, diagnosis requires at least 2 of the following 3 features: (1) abdominal pain compatible with pancreatitis, (2) serum amylase or lipase activity $\ge 3$ times the upper limit of normal, and (3) imaging findings consistent with acute pancreatitis.
Explanation:
• While both amylase and lipase are released from acinar cells during pancreatic injury, Serum Lipase is significantly more sensitive ($95\text{--}100\%$) and specific ($95\text{--}99\%$) than serum amylase for confirming acute pancreatitis.

• Serum amylase is produced by salivary glands as well as non-pancreatic tissues (intestine, ovary, fallopian tubes); thus, hyperamylasemia can be falsely elevated in parotitis, diabetic ketoacidosis, renal failure, and intestinal obstruction.

• Serum lipase is synthesized almost exclusively by the pancreatic acinar tissue, minimizing false-positive results.

• Lipase rises within 4--8 hours of symptom onset, peaks at 24 hours, and remains elevated for $8\text{ to 14\text{ days}$}, whereas amylase levels peak early and normalize rapidly within 48--72 hours due to renal clearance.

• Abdominal ultrasound is primarily used to evaluate biliary etiology (gallstones/sludge) but is often obscured by overlying bowel gas ($>30\%$ of cases). CT abdomen is not needed immediately for routine confirmation unless complications (necrosis/pseudocyst) are suspected after 72 hours.
Final Answer:
Serum lipase is the most sensitive and specific laboratory investigation to confirm acute pancreatitis.