An 8-year-old boy is accidentally hit in the abdomen by a baseball bat. After several minutes of discomfort, he seems to be fine. Over the ensuing 24 hours, however, he develops a fever, abdominal pain radiating to the back, and persistent vomiting. On examination, the child appears quite uncomfortable. The abdomen is tender, with decreased bowel sounds throughout, but especially painful in the midepigastric region with guarding. Which of the following tests is most likely to confirm the diagnosis?

While no diagnostic test is completely accurate, an elevated total serum amylase with the correct clinical history and signs and symptoms of pancreatitis is the best diagnostic tool. The causes of pancreatitis in children are varied, with about one-fourth of cases without predisposing etiology and about one-third of cases as a feature of another systemic disease. Traumatic cases are usually due to blunt trauma to the abdomen. Acute pancreatitis is difficult to diagnose; a high index of suspicion is necessary. Common clinical features include severe pain with nausea and vomiting. Tenderness, guarding or rebound pain, abdominal distention, and a paralytic ileus are often seen. Plain films of the abdomen may exclude other diagnoses; ultrasonography of the pancreas can reveal enlargement of the pancreas, gallstones, cysts, and pseudocysts. Supportive care is indicated until the condition resolves.