Exocrine Pancreatic Insufficiency

Exocrine pancreatic insufficiency (EPI) is a clinical diagnosis, characterized by insufficient digestive enzymes in the intestine to accomplish normal digestion and absorption of a meal. Humans have multiple mechanisms for nutrient digestion and absorption in addition to pancreatic enzymes, and these compensate for the lack of enzymes. EPI is very common in patients with chronic pancreatitis, pancreatic cancer, and after pancreatic surgery. EPI can also be seen less frequently in a number of other clinical situations. A major limitation in reaching a diagnosis of EPI is the lack of an accurate, specific, and widely available diagnostic test. Fecal elastase-1, the most commonly utilized diagnostic test, has limited specificity, and when used in a low prevalence population has many false positive results. Treatment of EPI requires appropriate dosage and timing of pancreatic enzyme replacement therapy (PERT), which is often not achieved in clinical practice. Failure to respond to PERT is most commonly due to inadequate dosage or wrong timing. Other reasons for PERT failure include acid inactivation of enzymes and alternative causes of maldigestion, malabsorption, or weight loss. Small intestinal bacterial overgrowth is the most common such cause, followed by the development of a secondary pancreatic or extra-pancreatic malignancy. In addition to PERT, ongoing monitoring for nutritional deficiencies and metabolic consequences of EPI is required.