Exocrine Pancreatic Insufficiency in Cats: Clinical Signs and Treatment Response

Cats with exocrine pancreatic insufficiency (EPI) often have clinical signs different from those of dogs, according to a report published in the Journal of Veterinary Internal Medicine. The authors recommend including EPI in the differential diagnosis of cats with unexplained weight loss, even if they have no diarrhea or other clinical signs. Cobalamin supplementation and low serum feline trypsin-like immunoreactivity (fTLI) were predictive of good clinical response to enzyme replacement treatment.

The study was conducted by researchers at Texas A&M University College of Veterinary Medicine (College Station, Texas). It is the largest case series of feline EPI published to date, according to the authors. Their aim was to characterize the clinical presentation a /news/australian-students-synthesize-daraprim-for-just-2 nd response to treatment in cats with EPI.

EPI is the inadequate production of digestive enzymes by the pancreas. It can be caused by chronic pancreatitis, masses that obstruct the pancreatic duct, or (in certain dog breeds) pancreatic acinar atrophy. In dogs, common clinical signs are polyphagia, weight loss, and loose, pale stools. EPI is typically treated with pancreatic enzyme supplementation or raw pancreas.

From March 2008 to January 2010, serum samples from 46,529 cats were submitted for measurement of serum fTLI concentration at Texas A&M. In 1095 cats (2.4%), serum fTLI concentration was 8 µg/L or below, considered diagnostic for EPI in cats. The researchers sent questionnaires about these cats to a random sample of 261 referring veterinarians and received 150 completed questionnaires.

The ages of cats with EPI ranged from 3 months to 18.8 years, with a median of 7.7 years. “This finding is important because EPI has been traditionally considered a disease of middle-aged to older cats,” write the authors. “The results of our study suggest that EPI should be considered in cats of any age.”

The clinical presentation of many of the cats with EPI was somewhat different from that of dogs with EPI, potentially leading to underdiagnosis in cats, say the authors. Clinical signs and the percentage of cats in whom they were reported were as follows:

• Weight loss, 91%
• Unformed feces, 62%; occasional watery diarrhea, 33%
• Poor hair coat, 50%
• Increased appetite, 42%
• Anorexia, 42%
• Lethargy, 40%
• Vomiting, 19%

The typical presentation in dogs with EPI is a combination of weight loss, unformed feces, and diarrhea. Slightly fewer than one-third (32%) of the cats with EPI had this combination of signs (56% had a combination of weight loss and unformed feces). “Therefore, EPI should be suspected in cats with unexplained weight loss or anorexia even when clinical signs that are considered classical for EPI in dogs (eg, diarrhea and polyphagia) are not present,” write the authors.

Serum cobalamin concentrations were below the reference range in 77% of the cats in whom it was tested. In 70% of cats, it was too low to be detected by the assay. Serum fTLI concentrations were significantly lower in cats with hypocobalinemia than in cats with normal serum cobalamin concentrations.

The most common concurrent medical problems in cats with EPI were gastrointestinal problems, reported in 20% of cats. Endocrine disorders (including diabetes mellitus), pancreatitis, and hepatic lipidosis were also reported.

Sixty percent of the cats given enzyme replacement treatment had a good response to treatment, according to subjective assessments by the referring veterinarians. The type of enzyme replacement product was not specified; none of the cats received raw pancreas. The two predictors of good clinical outcome were cobalamin supplementation and low serum fTLI concentration. The authors suggest that the presence of concurrent diseases and lack of cobalamin supplementation could have contributed to poor treatment response in some cats.

Cobalamin supplements were given to 49% of the cats with EPI, including some with normal serum cobalamin concentrations. Cats receiving cobalamin were 3 times as likely as other cats to have a positive response to enzyme replacement treatment, regardless of whether they were hypocobalinemic before treatment. The authors note that tissue stores of cobalamin decrease before serum levels drop, so cats with normal serum cobalamin concentrations could still have had cobalamin deficiency.

Low serum fTLI concentration (below 4 µg/L) was also a predictor of favorable response to enzyme replacement treatment. The authors suggest that cats with more severe disease could benefit more from treatment. It is also possible, they write, that the assay was not entirely accurate at levels below 8 µg/L, causing some cats to have been mistakenly diagnosed with EPI.

Antibiotic treatment, given to about half of the cats, did not affect treatment response. Antibiotics could have been given as trial therapy or to treat concurrent gastrointestinal or hepatic disease, say the authors.

Study limitations listed by the authors include the retrospective nature of the study, reliance on information from referring veterinarians, and subjective assessments of treatment response.

Dr. Laurie Anne Walden received her doctorate in veterinary medicine from North Carolina State University. After an internship in small animal medicine and surgery at Auburn University, she returned to North Carolina, where she has been in small animal primary care practice for over 20 years. Dr. Walden is also a board-certified editor in the life sciences and owner of Walden Medical Writing, LLC. She works as a full-time freelance medical writer and editor and continues to see patients a few days each month.