Thus, none of the complete blood count, serum chemistry profile, or urinalysis findings are specific for pancreatitis. However, these parameters can help you narrow your list of differential diagnoses for such nonspecific clinical signs as vomiting, anorexia, and lethargy. Also, general clinical pathology results will help you assess a patient's overall health status and may help you determine how aggressively to pursue further workup and management.

DIAGNOSTIC IMAGING

Radiography

Ultrasonography

Abdominal ultrasonography was first described as a diagnostic tool for pancreatitis in veterinary patients in the mid-1980s. Since then, both the technology and expertise of veterinary radiologists in this area have markedly increased. While this development has increased the sensitivity of this diagnostic modality for pancreatitis, it has decreased its specificity. The sensitivity of abdominal ultrasonography for pancreatitis when performed by a veterinary radiologist has been reported to be up to 68% in dogs and up to 35% in cats.^7,13

Ultrasonographic findings in dogs and cats with pancreatitis include pancreatic enlargement, changes in the echogenicity of the pancreas (hypoechogenicity is thought to indicate pancreatic necrosis and hyperechogenicity pancreatic fibrosis) and peripancreatic fat (hyperechogenicity is thought to indicate peripancreatic fat necrosis), fluid accumulation around the pancreas, a mass effect in the area of the pancreas, a dilated pancreatic duct, and a swollen major duodenal papilla. When stringent criteria are applied, abdominal ultrasonography is useful in identifying pancreatitis in dogs and cats.

Computed tomography

Abdominal computed tomography is routinely used in people suspected of having pancreatitis. But it appears to lack sensitivity for diagnosing pancreatitis in cats, and data in dogs are extremely limited.^8,14

MINIMALLY INVASIVE DIAGNOSTIC TESTS

Many minimally invasive diagnostic tests for canine and feline pancreatitis have been described, but few have been found to be clinically useful. However, one new test, pancreatic lipase immunoreactivity, has shown promise.

Serum lipase activity

Serum lipase activity has been used to diagnose human and canine pancreatitis for several decades.^15-17 However, it has long been recognized that serum lipase activity has low sensitivity and specificity for identifying pancreatitis in either species.

Serum lipase activity has been reported to decrease in dogs after pancreatectomy, indicating that some of the serum lipase activity originates from the exocrine pancreas.¹⁸ But considerable serum lipase activity is still present in these dogs after pancreatectomy, indicating that lipase activity must originate from additional sources.¹⁸ Many cell types synthesize and secrete lipases. Any time an apolar lipid, such as a triglyceride, needs to permeate the phospholipid bilayer of a cellular membrane, a lipase is needed. These lipases of different cellular origins share a common function, so they cannot be differentiated by using a catalytic assay such as those being used to determine lipase activity in serum.

To further illustrate this phenomenon, serum lipase activity was measured in 25 dogs with exocrine pancreatic insufficiency.¹⁹ These dogs had no apparent pancreatic functional reserve, yet in these 25 dogs the mean serum lipase activity did not differ significantly from that in 74 healthy dogs, and only one dog with exocrine pancreatic insufficiency had a serum lipase activity below the lower limit of the reference range.¹⁹