What causes EPI?
EPI in dogs is most frequently due to pancreatic
acinar atrophy, which is a condition uniquely common in the dog. It is
characterised by a progressive loss of the pancreatic cells that normally
produce powerful enzymes required for the initial degradation of food in
the small intestine. In EPI, fewer and fewer of these digestive enzymes
are produced, which ultimately leads to maldigestion and malabsorption
of nutrients. The situation is compounded by the fact that there may be
secondary gut damage, whereas EPI also predisposes the animal to the development
of small intestinal bacterial overgrowth (SIBO), which has an additional
negative effect on intestinal function.
The underlying cause of pancreatic acinar
atrophy is unknown. There is a high prevalence of EPI in German Shepherd
Dogs, in which breed the disease is reported to be heritable in an autosomal
recessive manner. A recent study has indicated that the pancreatic atrophy
is preceded by lymphocytic-plasmacytic inflammation, which suggests that
the disease may have an immune component. However, these are very preliminary
findings, and at present we have to assume that there is no definite cause,
and treatment remains symptomatic.
Signs
EPI may occur in a wide variety of dog breeds
and at any age, but two-third of EPI-cases in the UK are German Shepherd
Dogs. It typically presents in young adult dogs between 1 and 5 years of
age. Signs are ravenous appetite, weight loss despite the increased appetite,
and diarrhoea. Stools are voluminous, poorly formed and greasy-looking.
The hair coat is often in poor condition.
How to diagnose EPI
Since treatment of EPI requires lifelong replacement
therapy and judicious dietary management, an exact diagnosis is important.
Fortunately, this has been greatly facilitated by the availability of the
TLI-test. This is a simple, reliable and sensitive blood test, which measures
the amount of a pancreatic digestive enzyme (trypsinogen) in the blood
stream, providing an excellent indirect assessment of pancreatic function.
Dogs with EPI can be identified by a low blood TLI concentration. Marked
reductions in serum TLI concentration may precede the onset of clinical
signs of EPI, and assay of serum TLI has thus been useful for the early
identification of affected dogs. The TLI-test has replaced stool digestion
tests, which are insensitive and unreliable.
Treatment of EPI
Most dogs with EPI can be managed successfully
by supplementing each meal with pancreatic enzymes. Pancreatic powdered
extract seems to work best in the dog. In addition, a highly digestible,
moderately fat-restricted diet should be fed, which helps to overcome residual
digestive deficits. Vitamin B12 supplementation should be given to dogs
with low blood concentrations of this vitamin. Additional treatment,
for instance antibiotic treatment for bacterial overgrowth, may be required
in dogs that do not respond to standard management.
With adequate treatment, the outlook for dogs
with EPI is usually good, although the cost of enzyme replacement can be
substantial since dogs will require life-long treatment. |
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