Pancreatitis in cats (Proceedings)

Ultrasonography became part of the routine diagnostic method to evaluate pancreatic disorders in small animals at our hospital.  It is important to be familiar with the ultrasonographic appearance (location, size, shape, echogenicity) of the normal feline pancreas to best. 

The ultrasonographic (US) features of pancreatitis vary accordingly to the degree of pancreatic and peripancreatic tissue inflammation, and the stage of the disease process.  In cats, exocrine pancreatic disorders are more common than previously reported and chronic pancreatitis is more frequent than acute pancreatitis.   

Pancreatitis

Just like in dogs, the US features of pancreatitis can include: normal appearing pancreas, enlarged and locally or diffusely hypoechoic parenchyma, moderately hyperechoic (or mixed echogenicity) surrounding fat consequently to fat saponification, and peritoneal effusion. 

 In cats, The US features of pancreatitis are less consistent, but when present, the left limb of the pancreas is usually easier to visualize.  In a review of 20 cats with acute pancreatic necrosis, the pancreas was considered normal in 10 cats, and not seen in 3 cats.  Other studies have concluded that acute necrotizing pancreatitis cannot be reliably differentiated from chronic non-suppurative pancreatitis.  Thickened gastric/duodenal wall can be seen in association with pancreatitis.  Occasionally, the enlarged pancreas creates compression of the cystic/common bile duct.  In these cats, the common bile duct is dilated (normal diameter is less or equal to 4 mm) and tortuous up to the duodenal papilla.

Chronic pancreatitis characterized by interstitial fibrosis with acinar atrophy and lymphocytic infiltrates is rarely suspected clinically.   Most of the cases encountered are presented with vague clinical signs and non-specific laboratory values.   The common bile duct can be seen dilated in association with chronic pancreatitis.  In a review of 15 cats with histologically proven chronic pancreatitis, only 40% of the cats had evidence of pancreatic enlargement with decreased echogenicity and hyperechoic peripancreatic fat.  Parenchymal or ductal mineralization was seen in 3 cats.  The pancreatic duct was considered enlarged (>1.3 mm) in 6 cats (40%).  Cystic changes (retention and pseudocyst) associated with the pancreas were noted in 3 cats.   

In cats, the pancreatic duct can be dilated in both acute and chronic pancreatitis.  In a recent retrospective study, we found an incidence of 7.2% of cats diagnosed with dilated pancreatic duct in the population of cats seen in US, and was most commonly and seen in older cats.  In 41.3% of all cats, it was considered that the dilation was likely of no clinical significance.   It was concluded that a dilated pancreatic duct is not a reliable indicator of pancreatic disease.

 In cats, concurrent conditions such as hepatic lipidosis, cholangiohepatitis, enteritis/IBD, diabetes mellitus, and interstitial nephritis are commonly seen concurrently to pancreatitis; therefore, US of the entire abdomen should be performed to provide information that can contribute to the overall prognosis.

References

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Ferreri JA, Hardam E, Kimmel SE, Saunders HM, et al. Clinical differentiation of acute necrotizing from chronic nonsuppurative pancreatitis in cats : 63 cases (1996-2001).  Journal of American Veterinary Medical Association 2003;223 (4):469-474.

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Hittmair K.M., Gamperl E., Schwendenwein I., Reifinger M. Ultrasonography of pancreatic disease in cats. IVRA (abstract) Rio de Janeiro, 2009.