The diarrhea resolved by Day 8, but the vomiting persisted. The dog showed persistent restlessness and aggressiveness, especially when we tried to pick it up, which was interpreted as evidence of abdominal pain. Icterus of the sclera and pinna developed along with marked increases in the total serum bilirubin concentration (5.1 mg/dl, reference range = 0 to 0.8 mg/dl) and serum ALP activity (2,039 U/L, reference range = 24 to 147 U/L) and a decrease in the serum albumin concentration (1.6 g/dl, reference range = 2.4 to 3.6 g/dl). However, the patient's vital parameters remained normal. A repeat abdominal ultrasonographic examination revealed no major changes in the echogenicity of the pancreas, but the gallbladder was markedly distended, and the common bile duct (5.5-mm diameter) and duodenal walls were thickened (6 to 7 mm). Repeat serum cPLI concentration results were 416 µg/L, indicating ongoing pancreatic inflammation.

After several days of continued aggressive supportive care, including administration of nutritional support, antiemetics (ondansetron), analgesics (fentanyl constant-rate infusion at 3 µg/kg/hr), gastrointestinal protectants (ranitidine 2 mg/kg intravenously t.i.d.), and antibiotics (ampicillin 22 mg/kg intravenously t.i.d.), the dog finally began to improve; the vomiting and abdominal pain resolved. The results of a repeat abdominal ultrasonographic examination showed normalization of the size and appearance of the pancreas. And a repeat serum cPLI assay revealed a concentration of 226 µg/L, which is suggestive of pancreatic inflammation but compared with previous results was greatly decreased, paralleling the overall improvement in clinical signs and abdominal ultrasonographic findings.

Water was slowly reintroduced orally, and after several days, the patient began to drink readily with no vomiting or signs of abdominal pain. The dog was fed a canned low-fat diet (Royal Canin Veterinary Diet canine Low Fat LF) and boiled chicken and rice in small amounts several times a day with no vomiting or signs of abdominal discomfort. The serum cPLI concentration was 118 µg/L, which coincided with the resolution of the dog's clinical signs.

Unfortunately, the day the dog was to be discharged, it developed an acute onset of right-sided hemiparesis, decreased facial sensation, and ventral strabismus, most consistent with an intracranial embolic or ischemic event. The owner elected to have the dog euthanized. Necropsy revealed a pancreas that was white, firm, nodular, and thickened and had lobes shortened to about half of their normal size. A histopathologic evaluation of the pancreas revealed severe chronic interlobular fibrosis (multifocal) with mild interstitial inflammation. The intestinal lumen of the proximal duodenum was patent but had a restricted diameter because of the fibrosis. On cross section of the brain, an area of focal hemorrhagic necrosis was noted, suggestive of embolic cerebral necrosis.

DISCUSSION

Pancreatitis is one of the most challenging diseases to diagnose in veterinary medicine (see "Is it pancreatitis?" in this issue). This may be due, in part, to the vague clinical signs of pancreatitis; the wide variation of disease severity, ranging from subclinical to severe disease; or the lack of diagnostic tests that are both sensitive and specific for pancreatitis.¹ For example, abdominal radiography, complete blood counts, serum chemistry profiles, and urinalyses only reveal nonspecific changes and cannot be used to determine a definitive diagnosis.¹

Serum amylase and lipase activities have traditionally been used to diagnose pancreatitis in dogs. However, it has been suggested that about 50% of dogs with pancreatic inflammation have normal serum amylase and lipase activities and that about 50% of dogs with elevated activities of one or both of these enzymes do not have pancreatitis.⁵ This lack of specificity is due to the fact that the synthesis and secretion of both amylase and lipase is not limited to the exocrine pancreas. Thus, false increases in serum lipase activity have been described in dogs with hepatic, renal, or neoplastic diseases in the absence of pancreatic inflammation.^6,7 So measuring serum amylase and lipase activities to diagnose acute pancreatitis is only useful when the measuring can occur in-house and only if the diagnosis is later solidified with more specific diagnostic tests.