Acute pancreatitis is the most common gastrointestinal condition requiring hospital admission in the United States. This article summarizes the best available patient-oriented evidence for the diagnosis and treatment of acute pancreatitis.

Epidemiology

• The incidence of acute pancreatitis is approximately 5 to 80 cases per 100,000 people per year.^1–4

• Between the years 2001 and 2014, hospitalizations and costs related to acute pancreatitis steadily increased, likely because of the increased prevalence of obesity, an aging population, and gallstone-related disorders.^1–5

• Table 1 lists causes of acute pancreatitis.^6–13

Diagnosis

• Acute pancreatitis is diagnosed based on the revised Atlanta classification, which includes the presence of at least two of the following criteria: (1) upper abdominal pain, (2) serum amylase or lipase level more than three times the upper limit of normal, or (3) characteristic imaging findings.¹⁴

• The differential diagnosis of acute pancreatitis is shown in Table 2.

SIGNS AND SYMPTOMS

• Acute pancreatitis should be suspected in patients with sudden onset of left upper quadrant or epigastric abdominal pain, although it is sometimes painless. Pain often radiates to the back, worsens with eating or drinking, and is associated with nausea and vomiting.¹⁰

• Physical examination findings may include tenderness on palpation of the upper abdomen, decreased bowel sounds, fever, tachycardia, hypotension, or jaundice.¹⁰

• Overall, the history and physical examination have moderate accuracy when findings are abnormal (positive likelihood ratio = 3.2; negative likelihood ratio = 0.8).¹⁰

• Ecchymosis around the umbilicus (Cullen sign) or on the flank (Grey Turner sign) is present in only 3% of patients with acute pancreatitis and may occur with other diseases. Therefore, the diagnostic significance of these findings is low.^15,16

DIAGNOSTIC TESTING

• The accuracy of laboratory and imaging tests in the diagnosis of acute pancreatitis is summarized in Table 3.^6,10,17–19

• Serum lipase measurement should be the initial test in suspected acute pancreatitis, although serial measurements are not indicated. Amylase and lipase levels increase rapidly in pancreatitis, but serum amylase normalizes more quickly. Elevation of amylase or lipase that is more than three times the upper limit of normal strongly suggests acute pancreatitis.^18,20–22

• A urinary trypsinogen-2 level of more than 50 ng per mL on dipstick testing also suggests pancreatitis, but this test is not as widely available as serum amylase testing.¹⁸

• Laboratory evaluation should include a comprehensive metabolic panel, complete blood count, and triglyceride levels to aid in diagnosis and severity assessment. An aspartate transaminase level of more than 60 U per L (1.00 μkat per L) and an alkaline phosphatase level of more than 12 U per L (0.20 μkat per L) are helpful in the diagnosis of acute biliary pancreatitis, with positive predictive values of 90.2 and 81.9, respectively.^10,23

• Imaging is not required for the diagnosis of acute pancreatitis, although computed tomography can be useful to assess severity or in cases of diagnostic uncertainty, failure of conservative treatment, or clinical deterioration.^14,19,24

• Ultrasonography is useful in patients with suspected acute biliary pancreatitis; however, sensitivity for detection of gallstones is only 67% to 78%. Sensitivity of ultrasonography for choledocholithiasis is between 50% and 80%. Endoscopic ultrasonography is more accurate for choledocholithiasis, with a sensitivity of more than 90%, but it is more invasive.^25–27

• Magnetic resonance cholangiopancreatography is recommended when there is concern for acute biliary pancreatitis and the common bile duct is not adequately visualized or appears normal on ultrasonography. Magnetic resonance cholangiopancreatography has a similar sensitivity to endoscopic ultrasonography for detection of common bile duct stones that are 6 mm or larger.^25,28,29