From the Guidelines
The workup for pancreatitis should begin with a thorough history and physical examination, focusing on risk factors like alcohol use, gallstones, medications, and family history, and should include laboratory tests such as serum lipase and amylase, as well as imaging studies like abdominal ultrasound and CT scan with contrast, as recommended by the most recent guidelines 1. The initial evaluation should aim to establish the etiology of acute pancreatitis, which can be achieved in at least three fourths of patients through a combination of history, laboratory tests, and imaging studies 1. Key laboratory tests include:
- Serum lipase and amylase, with lipase being more specific
- Complete blood count
- Comprehensive metabolic panel
- Triglycerides
- Calcium levels Imaging studies are crucial, with:
- Abdominal ultrasound being the first-line test to evaluate for gallstones
- CT scan with contrast recommended if the diagnosis is uncertain or to assess for complications like necrosis or pseudocysts, typically performed 48-72 hours after symptom onset
- MRCP (magnetic resonance cholangiopancreatography) may be useful to evaluate the pancreatic and biliary ducts, especially when considering biliary causes
- Endoscopic ultrasound can help identify microlithiasis, tumors, or chronic pancreatitis changes, and is the preferred diagnostic test for unexplained acute and recurrent pancreatitis after an unrevealing initial evaluation 1. Severity assessment using scoring systems like Ranson's criteria, APACHE II, or BISAP should be performed to guide management decisions, as the severe form of the disease is associated with high hospital mortality rates 1. For patients with a first episode of pancreatitis without an obvious cause, additional testing for less common etiologies like autoimmune pancreatitis, genetic causes, or anatomic abnormalities may be warranted, with early risk stratification helping to determine if the patient requires intensive care monitoring or can be managed on a regular medical floor.
From the Research
Pancreatitis Workup
- The diagnosis of acute pancreatitis is usually based on the presence of abdominal pain and elevated levels of serum amylase and/or lipase 2.
- Serum lipase offers a higher sensitivity than serum amylase in diagnosing acute pancreatitis and has a larger diagnostic window, making it a useful diagnostic biomarker in early and late stages of acute pancreatitis 2.
- Several recent evidence-based guidelines recommend the use of lipase over amylase for the diagnosis of acute pancreatitis 2.
Diagnostic Criteria
- The diagnosis of acute pancreatitis requires the satisfaction of two out of three criteria:
- abdominal pain radiating to the back
- serum lipase or amylase levels three or more times the upper limit of the normal level
- findings indicating pancreatitis obtained via a computed tomography (CT) scan or magnetic resonance imaging (MRI) 3.
Initial Investigation
- The initial investigation for acute pancreatitis includes:
- serum amylase and lipase analysis
- a lipid panel including triglycerides
- analysis of immunoglobulins
- a full blood count
- electrolyte analysis
- a hemoglobin A1c test
- a complete metabolic panel
- transabdominal ultrasound 3.
Limitations of Serum Amylase and Lipase
- Serum amylase and lipase levels are not specific for pancreatitis and can be elevated in nonpancreatic conditions 4.
- Attempts have been made to validate newer biomarkers for the diagnosis of acute pancreatitis, including pancreatic elastase, serum trypsin, and urinary trypsinogen-activated peptide 4.
- The sensitivity and specificity of serum amylase and lipase can be affected by the cut-off levels used, with higher cut-off levels resulting in higher specificity but lower sensitivity 5.