A deficiency of the pancreatic enzymes for digestion can result in a number of malabsorption syndromes. These enzymes play a major role in digesting carbohydrates, proteins and fats as well as certain fat-soluble vitamins. The pancreatic enzymes are also dependent and assisted by other digestive enzymes in the mouth, stomach and small intestine, as well as the action of additional substances like bile. Therefore a deficiency or the absence of pancreatic enzymes, as a result of impaired production, secretion or activity, will not result in a total disruption of nutrient absorption.
Causes of Pancreatic Enzyme Deficiency
Exocrine pancreatic insufficiency may be due to :
- Chronic pancreatitis, and acute pancreatitis
- Cystic fibrosis
- Pancreatic resection (surgical removal)
- Pancreatic cancer
- Schwachman-Diamond syndrome
- John-Blizzard syndrome
- Pearson syndrome
However, the cause of the enzyme deficiency may not be rooted in the pancreas’ impaired production of digestive enzymes. The conditions below affects the release of all of the pancreatic digestive enzymes :
- Obstruction of the pancreatic duct in the event of pancreatic cancer may prevent the outflow of pancreatic enzymes from the pancreas.
- Gallstones (bile duct stones) may also impair the flow of pancreatic enzymes and often affects the outflow of bile as well.
- Less frequently, certain conditions may affect the factors that regulate the production and secretion of digestive enzymes – this include nerve disorders and diseases that affect the digestive hormones cholecystokinin (CCK) and secretin.
Certain conditions may only affect a few of the pancreatic digestive enzymes. The enzymes are still present but are either not able to act or remain inactivated.
- The lack of or reduced secretion of bile as seen in cirrhosis may affect the action of the pancreatic enzymes that digest lipids. This can lead to vitamin deficiencies due to a malabsorption of the fat-soluble vitamins A, D, E and K.
- Excessive amounts of acid in the duodenum or increased duodenal acidity as seen in Zollinger-Ellison syndrome can impair the action of pancreatic lipase and also contribute to fat malabsorption.
- A congenital deficiency of the enzyme enterokinase which is responsible for activating trypsinogen into trypsin can lead to a protein malabsorption.
Signs and Symptoms of Pancreatic Enzyme Deficiency
A deficiency or inactivity of the pancreatic enzymes should be confirmed with appropriate laboratory tests. – refer ro pancreas enzyme tests. Certain signs and symptoms may be present but should not be used to conclusively diagnose this disorder.
- Steatorrhea – fats in the stool
- Creatorrhea – protein in the stool
- Bloating and gas
- Unintentional weight loss in addition to the signs and symptoms associated with the specific vitamin deficiencies associated with the malabsorption of fat-soluble vitamins.
Other signs and symptom may be related to the causes of the pancreatic enzyme deficiency or inactivity.
Pancreatic Function Tests
Assessing the exocrine activity of the pancreas can be done with a number of pancreatic function tests. This range of laboratory tests will require blood, stool and/or intestinal secretions to detect the presence of pancreatic digestive enzymes.
Malabsorption can be determined by testing the blood for deficiencies or the stool for the presence of nutrients that should have been digested and absorbed within the gut. However, this type of nutrient testing is not always indicative of pancreatic insufficiency and could be due to a host of other causes that result in malabsorption.
Types of Tests
Tests for pancreatic enzymes in the blood, stool, intestinal secretions.
- Secretin stimulation test
- Fecal elastase
- Pancreolauryl test
- Benitromide test (BT-PABA)
- Serum trypsinogen test
- Fecal chymotrypsin
Secretin Stimulation Test
The secretin stimulation test is the gold standard. However, it is invasive and therefore not conducted frequently. The secretin stimulation test is conducted by inserting a tube down the mouth, past the esophagus and stomach and into the duodenum (duodenal intubation).
Secretin is then administered into the small intestine. This digestive hormone stimulates bicarbonate and water secretion from the pancreatic ducts which carries digestive enzymes out of the pancreatic acini and it also neutralizes acidic stomach chyme. The intestinal secretions are collected and analyzed over a period of 2 hours.
Fecal Elastase Test
In this test, a stool sample is analyzed (immunoassay) for the presence of elastase. This will indicate whether the pancreas is secreting digestive enzymes. It is preferred over the secretin stimulation test in that it avoids duodenal intubation, however, it is may not detect mild exocrine pancreatic insufficiency.
Fluoroscein dilaurate is administered orally and the pancreatic esterases (lipid digestive enzymes) should cleave it. Lauric acid is then passed out in the urine. It is accurate and preferable in that it avoids intubation. However, one of the drawbacks is that urine has to be carefully collected over a period of two days.
Also known as the bentiromide test, it involves the oral administration of the peptide bentiromide. The metabolites of this compound is then analyzed in the urine and provides an indication of the presence and activity of pancreatic peptidase (protein digestive enzymes). However, it is not conducted in some countries due to side effects.
Serum Trypsinogen Test
A blood sample is collected and analyzed for trypsinogen, the precursor of trypsin which is one of the main proteases in pancreatic enzymes. Elevated levels of trypsinogen may be indicative of conditions like acute pancreatitis, pancreatic cancer and cystic fibrosis. Normal or low levels may be seen in chronic pancreatitis.
Fecal Trypsin/Chymotrypsin Test
A stool sample is analyzed for trypsin or chymotrypsin. The presence of these enzymes (positive result) in the stool is normal but if absent (negative result), pancreatic insufficiency related to cystic fibrosis, acute or chronic pancreatitis should be suspected and investigated further.
Stool Tests for Malabsorption
- The most common of these tests is the fecal fat test. This is used to identify lipids in the stool which results in steatorrhea.
- A test for the presence of proteins in the stool (creatorrhea) may also be conducted but should be further assesed for the type of protein. Larger serum proteins are seen in protein-losing enteropathy rather than in malabsorption.
- Carbohydrates in the stool can be detected by the presence of reducing substances and also assessed by stool pH. Acidic stool (pH <5.5) is indicative of carbohydrate malabsorption.
None of these stool tests are conclusive for exocrine pancreatic insufficiency as there are various causes of malabsorption. Pancreatic function tests, as mentioned above, should be conducted to confirm the diagnosis.
Last updated on September 5, 2018.