From the Guidelines
Lipase should be ordered for a patient presenting with diarrhea when there is suspicion of acute pancreatitis or pancreatic exocrine insufficiency as the underlying cause, particularly if accompanied by symptoms such as steatorrhea, abdominal pain, or unexplained weight loss. This recommendation is based on the higher sensitivity and specificity of lipase for diagnosing pancreatic disorders, as well as its longer diagnostic window compared to amylase 1. According to the 2019 WSES guidelines for the management of severe acute pancreatitis, serum lipase is considered a more reliable diagnostic marker of acute pancreatitis than serum amylase, with a sensitivity of 79% and specificity of 89% 1.
Key considerations for ordering lipase in patients with diarrhea include:
- Presence of steatorrhea or fatty stools, which may indicate malabsorption due to pancreatic exocrine insufficiency
- Abdominal pain, especially in the upper abdomen that may radiate to the back, which is a common symptom of acute pancreatitis
- Unexplained weight loss, which can occur due to malabsorption in pancreatic exocrine insufficiency
- Risk factors for pancreatic disorders, such as alcohol abuse, gallstones, hypertriglyceridemia, or family history of pancreatic disease
It is essential to note that lipase levels can be elevated in non-pancreatic diseases, such as renal disease, appendicitis, or bowel obstruction 1. However, in the context of diarrhea and suspected pancreatic involvement, lipase remains a valuable diagnostic tool. Elevated serum lipase levels, typically greater than three times the upper limit of normal, can indicate acute pancreatitis, while low fecal elastase or fecal lipase levels may suggest pancreatic exocrine insufficiency 1.
From the Research
Lipase Order Criteria for Diarrhea Patients
- Lipase should be ordered for a patient presenting with diarrhea when there is a suspicion of acute pancreatitis, which can be indicated by abdominal pain radiating to the back, nausea, and vomiting 2, 3.
- The diagnosis of acute pancreatitis requires the satisfaction of two out of three criteria: (1) abdominal pain radiating to the back, (2) serum lipase or amylase levels three or more times the upper limit of the normal level, and (3) findings indicating pancreatitis obtained via a computed tomography (CT) scan or magnetic resonance imaging (MRI) 2.
- Patients presenting with dysentery-like infectious diarrhea and upper abdominal pain should be investigated for concomitant pancreatic reaction or acute pancreatitis, which seems more frequent in patients with enterocolitis due to enteroinvasive microbes, mostly non-typhoidal Salmonella 4.
Patient Profiles for Lipase Order
- Patients with a history of diabetes mellitus, hypertriglyceridemia, or alcohol use are at higher risk of developing acute pancreatitis and may require lipase ordering 5, 6.
- Nondiabetic, nonalcoholic, nonobese patients with drug- or diet-induced hypertriglyceridemia may also present with acute pancreatitis and require lipase ordering 6.
- Patients with severe diarrhea, renal impairment, and increased triglyceridemia are more likely to have pancreatic enzyme alteration or true acute pancreatitis 4.