In people, most cases of EPI are secondary to chronic pancreatitis,1 but the prevalence of cases of EPI that develop secondary to chronic pancreatitis in dogs is still unclear.2 Pancreatic fibrosis can affect the islet cells of the endocrine pancreas and the acinar cells of the exocrine pancreas.2 In one study, two of four dogs with EPI resulting from chronic pancreatitis also had diabetes mellitus.6 In people and dogs with EPI resulting from chronic pancreatitis, diabetes mellitus usually precedes the development of EPI.6
A potential cause of EPI is congenital hypoplasia of the pancreas. This cause has been proposed in puppies in particular,
although published data lack histologic evidence to support this theory.2,7
Rarely, pancreatic neoplasia can occlude the pancreatic duct, prohibiting release of pancreatic enzymes into the duodenum.
Although the ability of the pancreatic acinar cells to produce pancreatic enzymes may not be affected, clinical signs of EPI
EPI can affect any breed, but German shepherds may be overrepresented. The two breeds most commonly affected by pancreatic
acinar atrophy, German shepherds and rough-coated collies, are thought to have an autosomal recessive inherited form of the
disease.8,9 Other breeds overrepresented among dogs with EPI due to any cause include Cavalier King Charles spaniels, chow chows, and
English setters.7,10 The common causes associated with each commonly reported breed are listed in Table 1.
Table 1 Most Common Signalment and Causes of EPI in Dogs*
In a recent case report, pancreatic atrophy was described for the first time in several racing greyhound puppies. It is unclear
whether environmental factors contributed to the development of EPI in these dogs or whether a true breed predisposition to
this condition exists.11
The median age of dogs with EPI is variable, depending on the cause (Table 1).
Dogs with EPI present with signs of maldigestion, primarily weight loss despite an increased appetite and diarrhea or loosely
formed feces. Feces are usually yellow or gray, are increased in volume, and may appear undigested or pulpy. In most cases,
fecal consistency is loosely formed, but dogs may experience severe watery diarrhea initially. The diarrhea is usually accompanied
by steatorrhea, flatulence, and borborygmi. Some dogs with EPI also experience vomiting. Along with the weight loss, these
dogs may have a poor coat. They may also seem nervous, aggressive, or irritable as a result of abdominal discomfort.2,12,13
EPI rarely affects serum chemistry profile and complete blood count results. Amylase and lipase activities are not useful
in diagnosing EPI. Occasionally, a serum chemistry profile may reveal hypocholesterolemia due to fat maldigestion. Elevation
of alanine transaminase (ALT) activity has been documented uncommonly, although the cause of this is unknown. One theory is
that an increased uptake of hepatotoxins occurs through the compromised small intestinal wall.2
Dogs with marked weight loss and loss of intra-abdominal fat secondary to EPI may have decreased serosal detail on abdominal
radiographs. No specific ultrasonographic abnormalities have been reported in dogs with EPI.14
Pancreatic biopsies are rarely necessary for diagnosing EPI, and the results may be misleading if acinar atrophy, fibrosis,
or hypoplasia is not diffuse.2 Pathologic findings within the pancreas may help you determine the cause of EPI, but a diagnosis of EPI must be based on
findings from tests of pancreatic function rather than histologic appearance.