What are the initial steps for testing and treating suspected pancreatitis?

Testing for Suspected Pancreatitis

Measure serum lipase at admission as your primary diagnostic test—it is superior to amylase with better sensitivity (91% vs 62%) and remains elevated longer, making it the preferred enzyme marker for diagnosing acute pancreatitis. 1, 2

Initial Diagnostic Testing

Biochemical Confirmation

• Serum lipase ≥3 times the upper limit of normal is diagnostic for acute pancreatitis and should be obtained immediately at admission 1, 2, 3
• Lipase has superior specificity for pancreatic tissue and remains elevated for 8-14 days compared to amylase's 3-7 days, making it more reliable when patients present days after symptom onset 1
• If lipase is unavailable, serum amylase ≥4 times normal is acceptable, though less sensitive particularly in alcoholic pancreatitis 4, 1
• The degree of enzyme elevation does NOT correlate with disease severity—patients can have severe pancreatitis with modest elevations 2

Mandatory Etiologic Workup at Admission

All patients require the following laboratory tests at presentation to identify the underlying cause (which should be established in ≥75% of cases): 4, 1

• Liver function tests (bilirubin, AST, ALT, alkaline phosphatase) to evaluate for gallstone pancreatitis—the most common etiology 4, 1
• Serum triglycerides to identify hypertriglyceridemia (levels >1000 mg/dL are diagnostic as the cause) 4, 1
• Serum calcium to assess for hypercalcemia as a potential etiology 4, 1

Initial Imaging

• Abdominal ultrasound should be performed at admission in all patients to detect gallstones, bile duct dilation, and free peritoneal fluid 4, 1
• Ultrasound has limited diagnostic value for visualizing the pancreas itself (inadequate in 25-50% of cases), but is critical for identifying gallstones in patients with severe disease who may need urgent ERCP 4
• Chest and abdominal plain x-rays should be obtained routinely to exclude other life-threatening pathology such as perforated viscus, intestinal obstruction, or leaking abdominal aortic aneurysm 4

Severity Assessment (Within 48 Hours)

Laboratory Markers for Severity

• C-reactive protein (CRP) >150 mg/L measured at 48 hours after symptom onset is the preferred laboratory marker for predicting severe disease 4, 1, 2
• APACHE II score >8 is the recommended clinical scoring system for severity stratification 4, 1, 2
• Hematocrit >44% is an independent risk factor for pancreatic necrosis 1
• Blood urea nitrogen >20 mg/dL independently predicts mortality 1

Advanced Imaging for Severe Disease

• Contrast-enhanced CT should be performed AFTER 72 hours (not earlier) in patients with APACHE II >8 or evidence of organ failure, as early CT underestimates the extent of pancreatic necrosis 4, 1, 2
• CT is also indicated when clinical and biochemical findings are inconclusive for diagnosis 4
• For patients >40 years with unexplained pancreatitis, CT or endoscopic ultrasound should be performed to rule out underlying pancreatic malignancy 4, 3

Initial Treatment Priorities

Immediate Supportive Care

All patients require: 4, 1

• Vigorous intravenous fluid resuscitation (this is the most critical initial intervention)
• Supplemental oxygen as needed
• Correction of electrolyte and metabolic abnormalities
• Adequate pain control

Nutritional Support

• Provide nutritional support in patients likely to remain NPO for >7 days 4, 1
• Nasojejunal tube feeding with elemental or semi-elemental formula is strongly preferred over total parenteral nutrition 4, 1

Urgent Interventions for Gallstone Pancreatitis

• Urgent ERCP within 24 hours is mandatory for patients with concomitant cholangitis 4, 1
• Early ERCP within 72 hours should be performed when there is high suspicion of persistent common bile duct stone (visible stone on imaging, persistently dilated CBD, or jaundice) 4, 1

Critical Pitfalls to Avoid

• Do NOT routinely administer prophylactic antibiotics in mild pancreatitis—they are only warranted for specific documented infections (chest, urine, bile, or line-related) 1
• Do NOT perform extensive invasive evaluation in patients <40 years with a single episode of unexplained pancreatitis—reserve this for recurrent episodes 4, 1
• Do NOT rely on clinical assessment alone—it will misclassify approximately 50% of patients and must be supported by objective laboratory and imaging findings 2
• The diagnosis must be established within 48 hours of admission to avoid missing alternative life-threatening intra-abdominal catastrophes 4, 3