Lecture Link: Canine pancreatitis: Insight from an internist

We all know how difficult the diagnosis and treatment of canine pancreatitis can be. In his presentation at the 2014 American College of Veterinary Internal Medicine Forum, "Canine pancreatitis: No such thing as a typical case," Michael Willard, DVM, MS, DACVIM, shared his experience in the management of these cases.

Diagnostic insight

While the history and physical examination are critical components of patient assessment, their utility in these cases has more to do with looking for and ruling out diseases that can mimic pancreatitis. Data collected from the minimum databases (complete blood count, serum chemistry profile, and urinanalysis) will also help. Dr. Willard pointed out that, unlike before, we have come to know that amylase and lipase activities are not reliable markers of pancreatitis. Hyperlipidemia is not a common finding, but if it is noted in a patient with an acute onset of vomiting and diarrhea, pancreatitis should be high on the differential diagnosis list.

According to Dr. Willard, trypsin-like immunoreactivity (TLI) is not a very sensitive indicator of pancreatic inflammation but may be supportive if it is elevated. The canine pancreatic lipase immunoreactivity (cPLI) assay, on the other hand, is very sensitive (85% to 90%), but its specificity is questionable. Even a small, perhaps not clinically significant foci of inflammation in the pancreas can cause a positive result, he noted. The best use of cPLI is in ruling out pancreatitis if the results are negative.

Abdominal radiography is indicated in these cases to look for other problems as well; classic signs of pancreatitis (e.g. loss of detail in the right cranial quadrant, dilated duodenum) are not always present. Abdominal ultrasonography is the most useful imaging modality we have for diagnosing pancreatitis, but it is not perfect. Dr. Willard pointed out that he has seen some cases in which sonographic changes lag behind clinical signs, so serial ultrasonographic examinations may be needed. Findings may change even within a few hours.

Pancreatic abscesses may occur and are typically sterile, so they can often be treated medically with ultrasound-guided drainage. Septic abscesses may be more common in cats, Dr. Willard noted. In his experience, pancreatic masses are more often inflammatory in nature than cancerous masses and may not require surgical removal unless insulinoma is suspected. A biopsy will be needed for a definitive diagnosis.

One of the biggest challenges with this disease is pets with severe clinical signs and whether they have severe sterile pancreatitis versus septic peritonitis. These conditions may look similar in that they both can have abdominal effusion, and bacteria may not always be seen even in cases of septic peritonitis. The abdominal fluid in both cases may be variably inflammatory.

Treatment tips

In terms of management, Dr. Willard offered the following:

> Offer low-fat food as soon as possible. You may consider this step even if there is some low-grade vomiting as long as feeding does not make the patient worse. Be sure to start slow.

> Begin fluid therapy. We tend to underestimate a patient's need for fluids, so err on the side of more in the absence of cardiac or renal disease. Hydration status may be difficult to assess in obese (no skin tent) or nauseated dogs (moist mucous membranes due to nausea).

> Since there are no robust studies, it is controversial whether fresh frozen plasma provides any benefit. It can be used if you suspect disseminated intravascular coagulopathy.

> Consider administering colloids. You can consider hetastarch if the albumin concentration is < 2 mg/dl (will provide more oncotic support than plasma).

> Total or partial parenteral nutrition is rarely needed.

> Administer analgesics. Consider butorphanol for very mild cases, methadone for moderate cases, and hydromorphone or fentanyl for severe cases.

> Only use antiemetics if vomiting or nausea are severe; otherwise, they may mask improvement. Dr. Willard recommended maropitant as a first-line drug.

> Consider proton pump inhibitors for dyspepsia-pantoprazole or omeprazole.

> Administer antibiotics only for severe cases or those with suspected systemic inflammatory response syndrome. If possible, consider sample collection (e.g. peritoneal fluid, aspirated abscess material) before antibiotic administration.

> Since their use in pancreatitis is controversial, reserve corticosteroids for patients that are not responding to therapy and then consider a physiologic dose.