What does the Pancreas Normally Do ?

The pancreas is a small light pink glandular organ located under the stomach and alongside the duodenum, which is the upper small intestine.  The “endocrine” pancreas is the part of the pancreas that secrets hormones like insulin and glucagon which regulate blood sugar.   The “ exocrine “ pancreas produces enzymes used to digest food.  Both the endocrine and exocrine pancreatic tissues are all mixed together throughout the entire pancreas.

Digestive enzymes include amylase to digest starches, lipase to digest fats, and trypsin & proteases to digest proteins.  They are stored inside special granules in the exocrine pancreatic tissue and are secreted into the duodenum (the first part of the small intestine coming out of the stomach) when ground up food leaves the stomach into the intestine.  Once nutrients are broken down into smaller molecules, they can be absorbed from the entire length of the GI (gastrointestinal) tract.  If we don’t have enough enzymes or our bodies don’t produce enough, the digestion of food is difficult if not impossible because the body can’t absorb the food resulting in losing weight, and having a rather nasty greasy diarrhea.  A dog will develop a dry, dandruffy coat from inability to absorb dietary fats.

Exocrine Pancreatic Insufficiency (also called “ Maldigestion”)

The most common cause of digestive enzyme deficiency in dogs is “pancreatic acinar atrophy,” where the pancreas simply becomes shriveled up and useless.   It seems to have a genetic basis, but is not congenital and may develop at any age - usually before 4 years of age. 

In German Shepherd Dogs and Rough-Coated Collies as the mode of inheritance appears to be autosomal recessive and involves immune-mediated destruction of the pancreas 

Special Testing For Diagnosis

The biggest discovery in the diagnosis of Exocrine Pancreatic Insufficiency is the Serum Trypsin-like Immunoreactivity test, which is a blood test, so is non-invasive.  The TLI test looks for a normal level of trypsin-like enzyme in the bloodstream.  In normal animals, trypsin, which is an enzyme of protein digestion, is stored in the pancreas in an inactive form so as to avoid digestion of the host’s body.  Trace amounts of active enzymes always make it to the bloodstream.  This is harmless, normal, and very detectable.  A dog or cat with   Exocrine Pancreatic Insufficiency (ETI ) will have almost no Serum Trypsin-like Immunoreactivity in the bloodstream.

The Fecal Protease Test is used to detect protein digesting enzymes in a stool sample.  Fasting the dog is not necessary, but, 3 consecutive samples are required to get a consistent result as there is a huge variability in fecal enzyme activity over the day.

The Fecal Elastase test is the newest test and is only available to test dogs.  Elastase is another digestive enzyme.  This test only requires a single stool sample, however the problem is that sometimes normal dogs will test negative for Elastase.  This means that EPI can be ruled out when the Elastase test is positive but not confirmed when it tests negative. 

Treatment

Dietary supplementation with digestive enzymes is an effective therapy.  Powdered enzymes seem to work the best though tablests are also available. A high digestibility diet is the best choice for EPI and should be low in fiber and fat and are thought to help with weight gain.

EPI patients generally have an overgrowth of bacteria in the intestines, which means the unabsorbed nutrients in the tract have fed the bacteria living there, instead of the patient.  This results in a vitamin B-12 deficiency as the bacteria consumes the vitamin instead of the patient getting the vitamin.  A course of antibiotics will help to correct this.  Also periodic shots of Vitamin B-12 have also been recommended.

Treatment is for life.  Without enzyme supplementation, all the unpleasant symptoms will recur.  A response to therapy is usually seen within a week of beginning treatment.  One dog in 5 will not respond well and many never regain back a normal weight.