Diagnostic Approach for Pancreatitis

Clinical Diagnosis

Patients typically present with upper abdominal pain and vomiting, with features of epigastric or diffuse abdominal tenderness 2
Body wall ecchymoses such as Cullen's sign (periumbilical) or Grey-Turner's sign (flank) may be evident in severe cases 2

Serum lipase is the preferred diagnostic marker for pancreatitis with greater specificity than amylase 1, 2
Lipase offers a larger diagnostic window than amylase since it remains elevated for 8-14 days versus 3-7 days for amylase 3, 4
Diagnosis is typically made when lipase is elevated to greater than 2-3 times the upper limit of normal 1, 2
Serum lipase has a sensitivity of 79% and specificity of 89% for acute pancreatitis according to Cochrane data 3
In the absence of gallstones or significant alcohol use history, serum triglyceride should be measured and considered the etiology if >11.3 mmol/l (>1000 mg/dl) 3, 4
Liver function tests (bilirubin, AST, ALT, alkaline phosphatase) should be obtained to evaluate for biliary obstruction 2
Serum calcium levels should be checked to identify hypercalcemia as a potential cause 1, 2

Abdominal ultrasonography should be performed at admission to look for gallstones or bile duct stones, pancreatic inflammation, and free peritoneal fluid 1, 2
CT scan is indicated when clinical and biochemical findings are inconclusive, assessment of severity is needed, or patients have predicted severe disease or evidence of organ failure 1, 2
MRCP or endoscopic ultrasound (EUS) should be used to screen for occult choledocholithiasis or to rule out pancreatic malignancy in unexplained pancreatitis in patients over 40 years 1, 2

Laboratory markers of severity include C-reactive protein ≥150 mg/L at 48 hours after onset, hematocrit >44%, urea >20 mg/dl, and procalcitonin 2, 3, 4
The APACHE II scoring system with a cutoff of 8 is recommended to predict severe disease 1
CT Severity Index combining assessment of pancreatic inflammation and necrosis correlates with increased morbidity and mortality 2
Early CT scanning (within first 72 hours) might underestimate pancreatic necrosis 1