Page 653 - Small Animal Internal Medicine, 6th Edition

CHAPTER 37 The Exocrine Pancreas 625

may also be a trigger, particularly potassium bromide, aza- frequent bowel movements) accompanied by some fresh
thioprine, or asparaginase in dogs. Concurrent endocrine blood because of local peritonitis in the area of the transverse
VetBooks.ir diseases such as hypothyroidism, hyperadrenocorticism, or colon. Inflammatory bowel disease, low-grade infectious
enteritis, chronic food intolerance, and chronic hepatitis are
DM increase the risk of severe fatal pancreatitis in dogs;
therefore it is important to identify these in the history. In
cats. Animals that are still eating may show prominent post-
cats the history may include features of concurrent cholan- major differential diagnoses for this presentation in dogs and
giohepatitis, inflammatory bowel disease, hepatic lipidosis, prandial discomfort.
or any combination of these. Cats and dogs with acute pancreatitis can present with
The clinical signs in dogs vary with the severity of the jaundice at initial examination or often developing a few
disease, from mild abdominal pain and anorexia to acute days later, when the initial acute signs are resolving. Most, if
abdomen and potential MOF and DIC. Dogs with severe not all, animals with pancreatitis and jaundice have acute-
acute disease usually present with acute onset of vomiting, on-chronic disease (see later, “Chronic Pancreatitis”).
anorexia, marked abdominal pain, and varying degrees of Careful clinical examination should focus on the identi-
dehydration, collapse, and shock. The vomiting is initially fication of the degree of dehydration and shock, careful
typical of delayed gastric emptying resulting from peritoni- assessment for any concurrent diseases (particularly endo-
tis, with emesis of undigested food a long time after feeding, crine disease), and careful abdominal palpation. In severe
progressing to vomiting only bile. The main differential diag- cases, petechiae or ecchymoses suggestive of DIC may be
noses in these cases are other causes of acute abdomen, identified, and there may be respiratory distress associated
particularly intestinal foreign body or obstruction; the vom- with acute respiratory distress syndrome. Careful clinical
iting may be so severe that the dog may undergo an unnec- and clinicopathologic assessment of the degree of shock and
essary laparotomy for a suspected obstruction if a careful concurrent organ damage is important for prognosis and
workup was not performed first. Some patients may show treatment decisions (see later). Abdominal palpation should
the classic so-called praying stance, with the forelegs on the identify pancreatic pain and rule out, if possible, any pal-
floor and the hind legs standing (Fig. 37.3), but this is not pable foreign bodies or intussusceptions, although abdomi-
pathognomonic for pancreatitis and can be seen in asso- nal imaging may be required to rule these out with confidence.
ciation with any painful condition in the cranial abdomen, In severe cases, generalized peritonitis will result in general-
including hepatic, gastric, or duodenal pain. By contrast, cats ized unmistakable abdominal pain in dogs, whereas in
with severe, fatal, necrotizing pancreatitis usually have sur- milder cases careful palpation of the cranial abdomen is
prisingly mild clinical signs, such as anorexia and lethargy; required to identify a focus of abdominal pain (Fig. 37.4); in
vomiting and abdominal pain occur in fewer than half of the cats, pain may not be apparent. Occasionally, a cranial
cases. Unlike dogs, cats often demonstrate remarkably little abdominal mass representing a focus of fat necrosis may be
abdominal pain on examination in spite of severe peritonitis. palpated, particularly in cats.
At the milder end of the spectrum, dogs and cats may
present with mild gastrointestinal signs, typically anorexia Diagnosis
and sometimes some mild vomiting, followed by the passage The clinician should be aware that there are many other
of some colitic-like feces (e.g., tenesmus, hematochezia, diseases that produce similar clinical presentations to acute
pancreatitis, and some of these might also be associated with
elevations in pancreatic enzymes. Some form of diagnostic
imaging is recommended together with blood sampling to
rule out more serious primary diseases, such as a perforating
foreign body.

Routine clinical pathology
Routine laboratory analysis (i.e., complete blood count
[CBC], serum biochemical profile, and urinalysis) typically
does not help in arriving at a specific diagnosis, but it is very
important to perform these in all but the mildest cases
because they provide important prognostic information and
aid in effective treatment (see later). Typical clinicopatho-
logic abnormalities in dogs and cats with acute pancreatitis
are shown in Table 34.3.

Specific pancreatic enzyme assays
FIG 37.3
Dog exhibiting evidence of cranial abdominal pain by More specific tests for the pancreas are the catalytic assays
assuming the so-called position of relief. (Courtesy Dr. for amylase and lipase, the new catalytic assay DGGR lipase
William E. Hornbuckle, Cornell University, College of and the immunoassays for trypsin-like immunoreactivity
Veterinary Medicine, Ithaca, NY.) (TLI) and pancreatic lipase immunoreactivity (PLI). More