Visiting Vet: Exocrine pancreatic insufficiency

What happens when your pet suddenly starts losing weight?

With EPI, food goes in one end and out the other without being fully “processed.” — Courtesy DogsArena

Ginger and Snap, two lovely tortoiseshell sisters adopted together as kittens, had the quintessential Island life, summers sunning in the yard or on the porch, winters sleeping by the wood stove. Other than random altercations with neighboring cats or other minor concerns, they rarely needed my services. Then, when the girls turned 5, Ginger started losing weight. She had been plump to begin with, and was feeling fine, so at first we weren’t too concerned, but as months passed, she continued getting thinner, despite eating more than usual.

When an otherwise healthy cat is eating excessively but losing weight, two diseases top our differential list — diabetes and hyperthyroidism. These are easily diagnosed with routine blood tests, but Ginger’s results were normal. Normal blood sugar. Normal thyroid levels. “I know she’s a big hunter,” I said, “and many cats lose weight in the summer. Let’s deworm her and recheck in the fall.”

By October, Ginger had dropped from an initial hefty 13 pounds down to less than 9. Even though 9 pounds is an ideal size for her, losing 30 percent of one’s body weight without trying is simply not normal. Although still eating, Ginger was now listless, and significantly less active than usual. “Is she vomiting?” I asked. “What do her stools look like?” Except for occasionally barfing grass, Ginger was not throwing up. Her bowel movements looked fine. I scratched my head. Several possibilities came to mind. Cancer had to be considered; intestinal lymphoma is one of the most common malignancies in cats, even those as young as Ginger. Next was inflammatory bowel disease (IBD), a disease of unknown cause affecting the gastrointestinal tract. Another possibility was “occult” hyperthyroidism, which is too complicated to explain here. You’ll just have to trust me, it was on the list.

Additional diagnostic tests ruled out occult hyperthyroidism, as well as feline leukemia and feline immunodeficiency viruses, which can present as unexplained weight loss. Radiographs did not yield anything specific, though the gas patterns on the film led one specialist to speculate about partial intestinal obstruction. Ginger’s signs were not classic for foreign-body ingestion, but young cats tend to eat things they shouldn’t. We couldn’t completely eliminate the possibility she ate something that stuck in her gut. We discussed referral for abdominal ultrasound, and possible exploratory surgery to rule out foreign-body obstruction and take intestinal biopsies which could give definitive answers about IBD or cancer. “There’s one set of tests to do before any invasive procedures,” I decided. “Let’s check for exocrine pancreatic insufficiency.”

The pancreas is an abdominal organ with two functions. It secretes hormones like insulin to control blood sugar. It also produces enzymes that help digest food. In exocrine pancreatic insufficiency (EPI), the animal does not make enough digestive enzymes. Without these enzymes, the body cannot break down food, and nutrients are not absorbed properly. Food goes in one end and out the other without being fully “processed.” This may be reflected by voluminous, greasy, smelly stools. The inability to digest and absorb nutrients leads to malnutrition, weight loss, and vitamin deficiencies, as well as secondary problems such as bacterial overgrowth and damage to the intestinal lining.

In dogs, EPI is typically an inherited condition seen in young adult German shepherds and rough-coated collies, though it can occur in any dog as a result of pancreatitis or pancreatic cancer. In cats, EPI is very uncommon, though recent studies suggest it may be being underdiagnosed. Chronic pancreatitis is the usual underlying cause in kitties. Other diseases, such as cancer, may sometimes be involved.

After having Ginger fast for 12 hours, we drew blood and sent a “gastrointestinal panel” to the veterinary laboratory at Texas A&M University, where much of the cutting-edge work on EPI has been done. When all the numbers were finally in, we had confirmation. Ginger was indeed suffering from exocrine pancreatic insufficiency, with secondary B vitamin deficiency. I must admit, I was surprised. Most EPI cases I have seen over my career looked really sickly and had more clinical signs — poor hair coat, vomiting, and nasty, fetid stools often described as “pale, loose, voluminous, and greasy.” Ginger had exhibited only weight loss, increased appetite, and, recently, mild lethargy. Feline specialists reassured me that cats with EPI often present with less dramatic signs than dogs. I also credit Ginger’s family with being both astute observers and dedicated owners willing to pursue the necessary diagnostics.

Treatment consists of providing the digestive enzymes Ginger lacks by mixing a commercial powder made from dried pancreas into her food at every meal. Being a typical finicky feline despite her increased appetite, she needed a little persuasion to persuade her to eat the concoction. I suggested a tip learned recently at a conference: Duck fat. It’s available in gourmet stores for cooking. As long as it doesn’t cause diarrhea, a dab mixed in kitty’s food may add that je ne sais quoi needed to please her palate.

When I was in veterinary school, we were taught the enzyme-food mixture needed to “rest” for 20 minutes to “predigest” the food. Nowadays that theory has been debunked, and the mixture can often be fed immediately — but Ginger developed a common side effect. The enzymes irritated her lips. Going old school and letting the powder “incubate” in the food seems to make it less bothersome. We are also giving her cobalamin injections (vitamin B12), which she will likely need monthly for the rest of her life. In some EPI cases, antacids are advised, and, in others, antibiotic therapy to address the secondary issue of bacterial overgrowth.

Ginger is responding beautifully to treatment. She has gained weight, and is feeling spunky again. We’ll watch closely through coming months and years to be sure no other underlying issues emerge, but if all continues to go well, as long as she gets her supplements, Ginger should join her sister Snap for a long, idyllic Vineyard life. Summers sunning in the yard, winters sleeping by the wood stove.