What is the diagnosis for a patient presenting with abdominal (abdo) pain, elevated lipase levels indicating hyperlipasemia, no history of alcohol use, and a normal abdominal ultrasound with no evidence of common bile duct (CBD) or pancreatic duct dilatation, or cholelithiasis?

From the Guidelines

The patient's presentation of abdominal pain with an elevated lipase of 602 U/L is highly suggestive of acute pancreatitis, and I strongly recommend hospital admission for supportive care and further evaluation. The diagnosis of acute pancreatitis is supported by the combination of abdominal pain and lipase elevation, which is considered a more reliable diagnostic marker than serum amylase 1. According to the AGA institute medical position statement, elevations in lipase levels greater than 3 times the upper limit of normal are most consistent with acute pancreatitis 1.

Initial Management

The patient should receive IV fluids, typically lactated Ringer's solution at 5-10 mL/kg/hr initially, for aggressive hydration to prevent complications such as pancreatic necrosis or systemic inflammatory response syndrome. Pain management with opioid analgesics should be provided as needed, and the patient should be kept NPO initially, with diet advancement as symptoms improve, starting with clear liquids and progressing to a low-fat diet as tolerated.

Further Evaluation

Further evaluation should include a contrast-enhanced CT scan of the abdomen if symptoms persist beyond 48-72 hours to better visualize the pancreas, as ultrasound has limited sensitivity for pancreatic pathology 1. Additional laboratory tests should include comprehensive metabolic panel, complete blood count, triglycerides, and calcium levels to identify potential causes. Since alcohol is not a factor, other etiologies such as gallstone migration (despite current absence on ultrasound), medication effects, hypertriglyceridemia, hypercalcemia, or autoimmune causes should be investigated 1.

Laboratory Tests

The main reasons supporting lipase over both types of amylase for the diagnosis of acute pancreatitis include higher sensitivity and larger diagnostic window 1. A Cochrane revision showed a sensitivity and specificity of 72% and 93% for serum amylase, and 79% and 89% for serum lipase, respectively 1. In the absence of gallstones or significant history of alcohol use, serum triglyceride should be measured and considered to be the etiology if the value is > 11.3 mmol/l (> 1000 mg/dl) 1.

Severity Assessment

Many textbooks consider the C-reactive protein (CRP) as the gold standard for disease severity assessment, but its peak levels are reached only after 48 to 72 h 1. Other laboratory findings used to characterize an episode of severe acute pancreatitis are BUN > 20 mg/dl (> 7.14 mmol/l) 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.

From the Research

Abdominal Pain with Elevated Lipase

• The patient presents with abdominal pain and an elevated lipase level of 602 U/L, with no history of alcohol use and a normal abdominal ultrasound with no dilatation of the CBD or pancreatic ducts, and no cholelithiasis.
• Elevated lipase levels are typically associated with pancreatitis, but can also be seen in other conditions, such as infectious colitis 2 and hypertriglyceridemia 3.
• The diagnostic value of lipase in acute pancreatitis is well established, with lipase being a more specific marker than amylase 4.
• A systematic approach to patients with elevated lipase levels is critical to making an accurate diagnosis and initiating appropriate treatment, considering the broad differential diagnosis, including acute pancreatitis, chronic pancreatitis, gastrointestinal tract obstruction, malignancies, and other disease conditions 5.
• The diagnostic accuracy of hyperlipasemia in critically ill patients has been evaluated, with a positive predictive value of 38.1% and an optimal diagnostic lipase cutoff of 532 IU/L, highlighting the need for caution when interpreting hyperlipasemia in this population 6.

Differential Diagnosis

• Infectious colitis: a rare cause of elevated lipase without pancreatitis, as reported in a case study 2.
• Hypertriglyceridemia: a potential cause of acute pancreatitis, which can present with elevated lipase levels 3.
• Other conditions: such as gastrointestinal tract obstruction, malignancies, and other disease conditions, which can also cause elevated lipase levels 5.

Diagnostic Considerations

• Abdominal ultrasound: a normal ultrasound does not rule out pancreatitis or other conditions, and further evaluation may be necessary.
• Lipase cutoff: a higher lipase cutoff may improve diagnostic value in acute pancreatitis, but caution is needed when interpreting hyperlipasemia in critically ill patients 6.