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Diagnosis and management of feline pancreatitis (Proceedings)

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Aug 01, 2009

Feline pancreatitis is a very difficult disease to definitively diagnose antemortem (especially chronic cases or in cats that do not have persistent signs) and treatment remains symptomatic and supportive. The problems of diagnosis and treatment are due to the lack of specific clinical signs in cats, as well as the lack of a rapidly available test for diagnosis of the disease – and in cats with chronic pancreatitis, testing is still very difficult. This talk will review the salient features of both acute and chronic pancreatitis in cats and discuss the treatment of cats with pancreatitis.

Diagnosis

The clinical signs of feline pancreatitis are quite different from those in dogs. Two forms of pancreatitis appear to occur in cats: acute necrotizing pancreatitis(ANP) (a disease similar in appearance, if not cause, to canine acute pancreatitis), and lymphoplasmacytic pancreatitis (which can present as an acute or chronic disease). In a recent histologic review of pancreas' from cats that were submitted to postmortem for any cause (not just pancreatitis), the percentage of cats with ANP was less than 15%, while 65% of cats had LP changes. This illustrates that the feline disease is quite different from that recognized in the dog. The acute pancreatitis that is frequently encountered in obese dogs fed a high fat diet, is not reported in cats. Cats with acute necrotizing pancreatitis are more likely to be underweight, and high fat diets do not appear to be an important predisposing factor. In lymphocytic (LP) pancreatitis, cats of all ages, sexes and breeds are affected, although Siamese cats are reported to have pancreatitis more frequently. Finally the clinical signs of LP pancreatitis in cats are vague, with the most common signs being lethargy (reported in 100% of cats in one study), anorexia, dehydration and abnormal body temperature (either fever or hypothermia can be observed). This is especially true for cats with chronic or mild forms of LP pancreatitis. Vomiting and anterior abdominal pain, which are common clinical signs in dogs with acute pancreatitis, are reported to occur in only 35% and 25% of cats with LP pancreatitis, respectively, but are common in cats with ANP. However, cranial abdominal pain may be more common than is reported, as detection of abdominal pain may be difficult in obese cats or cats with very focal disease. Cats with the most severe forms of pancreatitis, such as acute necrotizing pancreatitis, may be icteric or in shock, and the prognosis for these cats is significantly more guarded. Other conditions that may occur concurrently with pancreatitis in cats include hepatic lipidosis, cholangiohepatitis, inflammatory bowel disease, interstitial nephritis, diabetes mellitus or vitamin K responsive coagulopathy. Thus, the clinical signs may be quite variable, and this must be taken into consideration with each patient. In addition, with increases in liver enzymes and bilirubin, the signs and abnormalities can easily be attributed to liver dysfunction, which further delays the diagnosis.

Routine evaluation of cats with suspected pancreatitis may include hematology, a serum biochemistry profile, urinalysis, abdominal radiography and/or ultrasound, and serum assays of pancreatic function (e.g. feline trypsin like immunoreactivity –fTLI, or feline pancreatic lipase immunoreactivity – fPLI). Hematologic findings in cats with pancreatitis are nonspecific, but may include a nonregenerative anemia, leukocytosis or leukopenia (less common). In a recent study, cats with pancreatitis consistently had an elevated WBC (20,300 cell/uL) and mild decreases in platelets (mean = 180,000 platelets/ul). Reported changes in the serum chemistry profile include elevated serum alanine aminotransferase (ALT), elevated serum alkaline phosphatase (ALP), hyperbilirubinemia, hyper- or hypoholesterolemia, hyperglycemia, azotemia, and hypokalemia. In a recent study, the most common abnormalities in cats with severe pancreatitis were hyperglycemia (180 mg/dL), hyperbilirubinemia (2.5 mg/dL), hypocholesterolemia (130 mg/dL), and hypoalbuminemia (1.8 g/dL). Liver enzyme elevations were more common in cats with mild pancreatitis (determined by surgical biopsy), and GGT ALP, and ALT were all moderately elevated in these cats. Hypocalcemia is less commonly observed, but when present may be a poor prognostic sign seen in cats with severe pancreatitis or multiple organ dysfunction. Serum lipase may be increased early in acute pancreatitis, but in a recent study amylase and lipase were found to be of little diagnostic value in distinguishing normal cats from those with pancreatitis. There are no changes in the urinalysis consistently observed or specific for pancreatitis in cats.