From the Guidelines
The diagnosis of acute pancreatitis requires at least two of three criteria: characteristic abdominal pain, elevated serum lipase or amylase levels at least three times the upper limit of normal, and characteristic findings on imaging studies. The abdominal pain is typically sudden in onset, reaches maximum intensity quickly, and may be associated with nausea and vomiting. Laboratory tests should be obtained promptly when pancreatitis is suspected, with lipase generally preferred over amylase due to its greater specificity and longer elevation period, as supported by a Cochrane revision that showed a sensitivity and specificity of 72% and 93% for serum amylase, and 79% and 89% for serum lipase, respectively 1. Imaging is not required for diagnosis if the first two criteria are met but is often performed to assess severity, identify complications, or rule out other causes of abdominal pain. Once diagnosed, severity assessment should be performed using scoring systems like the Revised Atlanta Classification, which categorizes pancreatitis as mild, moderately severe, or severe based on the presence of organ failure and local or systemic complications, as recommended by the 2019 WSES guidelines for the management of severe acute pancreatitis 1. Initial management includes fluid resuscitation, pain control, and addressing the underlying cause, which is most commonly gallstones or alcohol use. Some key laboratory findings used to characterize an episode of severe acute pancreatitis include BUN > 20 mg/dl or rising BUN, hematocrit (HCT) > 44% or rising HCT, lactate dehydrogenase (LDH), and procalcitonin for predicting infected necrosis in patients with confirmed pancreatic necrosis 1. It is also important to note that the diagnosis should be established within 48 hours of admission, and that serum lipase is considered a more reliable diagnostic marker of acute pancreatitis than serum amylase, with a larger diagnostic window and higher sensitivity 1.
Some key points to consider in the diagnosis and management of acute pancreatitis include:
- The importance of prompt laboratory testing and imaging to confirm the diagnosis and assess severity
- The use of scoring systems like the Revised Atlanta Classification to categorize the severity of pancreatitis
- The need for fluid resuscitation, pain control, and addressing the underlying cause in initial management
- The role of laboratory findings such as BUN, HCT, LDH, and procalcitonin in characterizing an episode of severe acute pancreatitis
- The preference for lipase over amylase in laboratory testing due to its greater specificity and longer elevation period.
Overall, the diagnosis and management of acute pancreatitis require a comprehensive approach that takes into account the patient's clinical presentation, laboratory findings, and imaging results, as well as the use of scoring systems and guidelines to inform treatment decisions, as supported by the 2019 WSES guidelines for the management of severe acute pancreatitis 1 and other studies 1.
From the Research
Diagnostic Criteria for Acute Pancreatitis
The diagnosis of acute pancreatitis requires the presence of at least two of the following criteria:
- Upper abdominal pain
- Serum amylase or lipase level greater than three times the upper limit of normal 2, 3
- Characteristic findings on imaging studies, such as cross-sectional imaging or ultrasonography 2, 4
Laboratory Tests
Laboratory tests used in the diagnosis of acute pancreatitis include:
- Serum amylase and lipase levels 2, 3, 5
- Urinary trypsinogen-2 dipstick test 5, 4
- Inflammatory markers, such as C-reactive protein (CRP) 2, 4
- Blood urea nitrogen (BUN), neutrophil-to-lymphocyte ratio (NLR), and heart rate, which are independent predictors of severe acute pancreatitis 6
Imaging Studies
Imaging studies, such as computed tomography (CT) and ultrasonography, can be used to:
- Assess the severity of acute pancreatitis 3
- Detect complications, such as fluid and/or necrotic collections 2
- Distinguish between biliary and non-biliary origin of the disease 4
Scoring Systems
Several scoring systems, such as Ranson's, BISAP, and APACHE-II, can be used to predict the severity of acute pancreatitis 3, 6. A new scoring system, the BHN score, has been developed, which uses BUN, NLR, and heart rate to predict severe acute pancreatitis 6.