Learn how to manage and treat these challenging EPI cases.
- Exocrine pancreatic insufficiency (EPI) is a syndrome characterized by the inadequate synthesis and secretion of pancreatic digestive enzymes due to severe damage to or lack of pancreatic acinar cells.
- Patients with an obstructed pancreatic duct or a deficiency in enteropeptidase in the small intestine have the same clinical signs and are thus also classified as having EPI, though they do not lack pancreatic enzymes.
- In general, EPI is due to a lack of functional pancreatic acinar cells, which in turn can be due to acinar atrophy or damage through chronic pancreatic inflammation (ie, chronic pancreatitis).
- Clinical signs are attributable to maldigestion and malabsorption of nutrients and develop after approximately 90% of the secretory capacity of the exocrine pancreas has been lost.1
►EPI primarily affects the gastrointestinal (GI) system.
- Genetic implications
►EPI is due to pancreatic acinar atrophy (PAA) in approximately 50% of cases (based on epidemiological data from the GI Laboratory at Texas A&M University; unpublished data, 2009).
►To date, PAA has only been described in German shepherds, rough-coated collies, and Eurasians.
►Although several studies have suggested an autosomal-recessive trait for PAA in German shepherds, a recent study has definitively shown that this condition is not caused by a simple autosomal-recessive trait.2
►The true incidence and prevalence remain unknown.
►Approximately 42% of all affected dogs are German shepherds (based on epidemiologic data from the GI Laboratory at Texas A&M University; unpublished data, 2009).
- Breed predilection
►EPI can be seen in any canine breed, but German shepherds, rough-coated collies, and Eurasians have a familial predisposition.
►Dogs with EPI attributable to PAA are typically young adults (1–2 years of age). Dogs with EPI due to chronic pancreatitis are often middle-aged to older but can be of any age.
►German shepherds are younger at the time of diagnosis than dogs of other breeds.
►No sex predilection has been reported.
EPI = exocrine pancreatic insufficiency, GI = gastrointestinal, PAA = pancreatic acinar atrophy
- Idiopathic PAA is the most common cause in German shepherds, rough-coated collies, and Eurasians. Lymphocytic infiltration before the onset of PAA suggests an immune-mediated pathogenesis.
- Chronic pancreatitis (Figure 1) can result in destruction of acinar cells (all breeds are affected, but cavalier King Charles spaniels and Jack Russell terriers may be predisposed).
- Other rare causes might include EPI due to pancreatic duct obstruction (eg, due to tumors or surgery), congenital aplasia, or pancreatic hypoplasia.
Clinical signs develop after approximately 90% of the secretory capacity of the exocrine pancreas has been lost.
- Breed predilection (see above)
- Factors predisposing to chronic pancreatitis
The true incidence and prevalence of exocrine pancreatic insufficiency remain unknown.
- Loss of pancreatic acinar cells leads to lack of digestive enzymes in the small intestinal lumen, leading to impaired nutrient absorption and transport and resulting in loose voluminous stools and weight loss.
- Undigested luminal food stuff may alter the intestinal microbiota, which may lead to dysbiosis.
- GI mucosal trophic factors, regulatory peptides, and intrinsic factor are also deficient in pancreatic secretions, leading to changes in small intestinal mucosal function and microanatomy.
- Generalized malnutrition might further affect the GI mucosa.
- Diabetes mellitus due to loss of islet cells has been reported in patients with EPI secondary to chronic pancreatitis but does not occur in patients with PAA.
►Weight loss despite a normal or increased appetite
►Foul-smelling loose stools
►Increased fecal volume with cow patty–like consistency (Figure 2)
►Increased number of defecations (usually >3/day)
►Coprophagia or even pica, flatulence, or borborygmus
►Polydipsia or polyuria in patients with concurrent diabetes mellitus
►Nervousness and aggression (rare)3
- Physical examination
►Poor body condition and muscle wasting (Figure 2)
►Poor-quality hair coat
Pancreatic atrophy and fibrosis. This section of pancreas is from a 10-year-old poodle. The pancreas is small and shows signs of remodeling, suggestive of chronic pancreatitis that has led to severe pancreatic atrophy and fibrosis. (Courtesy of Dr. John Edwards, Texas A&M University)