Serum Feline Trypsin‐Like Immunoreactivity in Cats with Exocrine Pancreatic Insufficiency

Abstract

Exocrine pancreatic insufficiency is thought to occur rarely in cats. This assumption has been made based on the lack of a specific test for this disease in the cat. Clinical data from the 1st 20 cats with serum feline trypsin-like immunoreactivity (fTLI) concentrations Յ8 g/L are presented. In 17 of these 20 cats compelling evidence for a diagnosis of exocrine pancreatic insufficiency (EPI) was present and in the remaining 3 supportive evidence for a diagnosis of EPI was available. The conclusion was made that serum fTLI concentration is a specific test for EPI in the cat.Key words: Chronic pancreatitis; Diarrhea; Fecal proteolytic activity; Weight loss.E xocrine pancreatic insufficiency (EPI) is caused by lack of synthesis and secretion of digestive enzymes by the exocrine pancreas. 1-4 Lack of pancreatic enzymes in the intestinal lumen causes nutrient malassimilation, resulting in weight loss and soft voluminous stools. [1][2][3] The exocrine portion of the pancreas has a large functional reserve, and human patients with chronic pancreatitis do not develop signs of EPI until more than approximately 90% of the exocrine pancreatic tissue has been destroyed. 4 As in humans, but in contrast to dogs, EPI in cats probably is caused most frequently by chronic pancreatitis. 3,5 Clinical signs reported in cats with EPI include weight loss, soft voluminous stools, and greasy soiling of the hair coat. 2,6 Unfortunately, a diagnosis of EPI is difficult to establish conclusively in cats. Although the clinical presentation may be compatible with a diagnosis of EPI, it is not specific for EPI. Routine laboratory tests may identify increased concentrations of hepatic enzymes, but these findings also are nonspecific and may be found in several other chronic gastrointestinal or systemic diseases. 2 Furthermore, findings on imaging studies, such as abdominal radiography or ultrasonography also are nonspecific. Finally, EPI is not a histopathologic diagnosis. Although a pancreatic biopsy may show histopathologic findings of atrophy, fibrosis, or lack of acinar tissue or zymogen granules within the acinar cells, in most cases some acinar tissue remains and the functional reserve of the exocrine pancreas cannot be estimated from the amount of acinar tissue observed histologically.Most tests of exocrine pancreatic function in cats are unreliable or impractical. 3,7,8 Fecal proteolytic activity has been shown to be useful in the diagnosis of EPI in the cat. 9,10 However, in order to acquire reliable results, at least 3 fecal samples from consecutive days must be collected, stored, and shipped frozen, and analyzed by methods that are not widely available. 10 The diagnosis of EPI in the dog has been improved greatly by the introduction of an assay for trypsin-like immunoreactivity (TLI) in serum. 11,12 This assay is sensitive and specific for the diagnosis of EPI in the dog. 12 A radioimmunoassay (RIA) and an enzyme-linked immunosorbent assay for feline TLI have been developed and validated recently. 13,14 Serum fTLI requires only a s...

Prevalence and Histopathologic Characteristics of Pancreatitis in Cats

“…8,22,27,29 The cause of pancreatitis in cats is still highly speculative and, according to Steiner and Williams, 90% of the cases are idiopathic. 37 Correlations have been found between inflammatory bowel disease (IBD) and cholangiohepatitis and the presence of CP. 40 Differentiation between the different etiologies of CP based on histopathologic morphology was not possible in this study.…”

“…Recent advances in diagnostic testing, including abdominal ultrasound and measurement of serum pancreatic lipase concentrations, have facilitated the antemortem diagnosis of feline pancreatitis, although pancreatic histology is still felt to represent the gold standard test for the diagnosis of feline pancreatitis. 19,21,30,35,37,42 Histopathology is still considered the most reliable diagnostic test for pancreatitis in the cat. 10,41,42 However, despite the high prevalence of feline pancreatic disease, no detailed description on the histopathologic nature of this disease is currently available in the literature.…”

American Association of Feline Practitioners: Senior Care Guidelines

“…✜ In addition to the MDB, initial evaluation should include measurement of feline pancreatic lipase immunoreactivity (fPLI), feline trypsin-like immunoreactivity (fTLI), B12 and folate concentration, which help create a specific treatment plan. 31,[81][82][83][84] …”

Selective fatty replacement of the exocrine pancreas in a domestic shorthair cat: histopathological findings with long-term outcome

“…In the past, EPI in cats has been considered rare; however, the introduction of assays for fTLI has made the diagnosis easier. 11 In this case, the fTLI measurement obtained at the time of pancreatic biopsy was 11.5 µg/l; values between 8.0 and 12.0 µg/l in cats are considered equivocal for EPI. This value implies the presence of some degree of residual exocrine pancreatic function at this point in time, which would be consistent with a 2 year survival time without any enzyme replacement therapy or cobalamin supplementation.…”