What is the significance of low amylase (Amylase) level of 24 in a patient with diarrhea?

From the Guidelines

An amylase level of 24 in a patient with diarrhea is indicative of pancreatic insufficiency, which can contribute to malabsorption and diarrhea, and therefore, the patient should undergo further evaluation with fecal elastase testing to confirm pancreatic exocrine insufficiency. This finding suggests that the patient's pancreas is not producing sufficient digestive enzymes, leading to undigested food in the intestines that draws in water and causes osmotic diarrhea 1. The normal range for amylase typically falls between 30-110 U/L, though reference ranges may vary slightly between laboratories.

According to the most recent and highest quality study, serum lipase is considered a more reliable diagnostic marker of acute pancreatitis than serum amylase, with a sensitivity and specificity of 79% and 89% for serum lipase, respectively 1. However, in this case, the low amylase level is more relevant to the diagnosis of pancreatic insufficiency rather than acute pancreatitis.

The patient should undergo further evaluation with fecal elastase testing to confirm pancreatic exocrine insufficiency. If confirmed, pancreatic enzyme replacement therapy (PERT) should be initiated, typically starting with a dose of 25,000-40,000 lipase units with each meal and 10,000-25,000 units with snacks, adjusting based on symptom response. The patient should take enzymes at the beginning of meals for optimal effect. Additionally, evaluation for underlying causes of pancreatic insufficiency such as chronic pancreatitis, cystic fibrosis, or pancreatic cancer is warranted. Patients may also benefit from a low-fat diet while enzyme therapy is being optimized to reduce steatorrhea symptoms.

Some key points to consider in the management of this patient include:

• The importance of confirming pancreatic exocrine insufficiency with fecal elastase testing
• The need for pancreatic enzyme replacement therapy (PERT) to manage symptoms and improve quality of life
• The importance of evaluating for underlying causes of pancreatic insufficiency
• The potential benefits of a low-fat diet in reducing steatorrhea symptoms.

From the Research

Significance of Low Amylase Level

• A low amylase level of 24 in a patient with diarrhea may not be directly related to the diagnosis of acute pancreatitis, as the studies suggest that elevated amylase and lipase levels are often encountered in clinical practice 2.
• The diagnostic yield of extensive investigation of patients with mild elevations of amylase and/or lipase is low, and the cost-effectiveness of such investigations warrants further study 3.
• However, it is essential to note that a low amylase level does not rule out the possibility of pancreatitis, as some cases of pancreatitis may have normal or low amylase levels 4, 5.

Diagnostic Considerations

• Serum lipase is recommended for the diagnosis of acute pancreatitis, both early and late in the disease, due to its higher diagnostic accuracy compared to amylase 6.
• The combination of lipase and amylase does not increase diagnostic accuracy, and the sensitivity of these enzymes for diagnosis is low 6.
• Other diagnostic thresholds, such as urinary total amylase and serum pancreatic isoamylase, may be considered, but their sensitivity and specificity vary 6.

Clinical Implications

• Patients with nonspecific abdominal pain and isolated elevations of amylase and/or lipase (less than three times the upper limit of normal) may not have identifiable pancreatic pathology 3.
• The presence of pancreatic-type pain and elevated amylase levels higher than 4-5 times the upper normal limit at 24 hours after ERCP may suggest the occurrence of pancreatitis 5.
• A systematic approach to patients with elevated amylase and/or lipase is critical to making an accurate diagnosis and initiating appropriate treatment 2.