Treating pancreatitis (Proceedings)

Treatment of the inciting cause

Whenever possible the inciting cause should be removed. However, as indicated above this may be difficult to accomplish as most cases of canine and feline pancreatitis are idiopathic. A serum chemistry profile should be performed to rule out hypertriglyeridemia and/or hypercalcemia. Exposure to unnecessary drugs, especially those implicated in causing pancreatitis in dogs, cats, or other species, should be avoided. Thus, first, a careful, drug history should be taken. Then, the clinician should determine whether treatment is needed. For example, a patient that is treated with an anticonvulsant medication probably should be maintained on some anticonvulsant therapy, but, if being treated with potassium bromide and/or phenobarbital should be changed to another anticonvulsant medication.

Aggressive fluid therapy is the mainstay of supportive therapy. Fluid, electrolyte, and acid-base imbalances need to be assessed, and corrected as early as possible. This is especially important since systemic complications are associated with a worse outcome and many of the systemic complications, once established, are difficult to treat.

Supportive care

The traditional recommendation for any patient with pancreatitis is to give nothing per os for three to four days. This recommendation may be justified in patients that vomit relentlessly. However, there is little evidence to justify this strategy in patients that do not. The issue is complicated further in cats by the fact that cats with pancreatitis often develop hepatic lipidosis. Preferred routes of alimentation are a jejunostomy tube or total parenteral nutrition. However, these strategies are impractical in many cases and a gastrostomy tube or a nasogastric tube are acceptable alternatives if a patient does not vomit. There is good evidence in human patients with pancreatitis that alimentation is crucial to counterbalance the catabolic effects of pancreatitis and a nasogastric tube has been shown to be quite effective in humans with pancreatitis. However, regardless of the mode of alimentation, a diet low in fat should be chosen. It is currently believed that this recommendation is far more important in dogs than in cats. In dogs or cats that do vomit relentlessly, the patient should be held NPO for 3-4 days. In cats alternative routes to oral alimentation must be pursued if the cat has been anorectic before presentation or if there is evidence to support concurrent hepatic lipidosis. After holding a patient NPO water is slowly reintroduced, followed by small amounts of a carbohydrate-rich and low-fat diet.

Analgesia

Abdominal pain is the key clinical sign in human patients with pancreatitis and is recognized in excess of 90% of all pancreatitis patients. Abdominal pain is much more commonly recognized in dogs than in cats with pancreatitis, but even in dogs the reported rate of abdominal pain is only approximately 58%. It is unlikely that abdominal pain occurs less frequently in dogs than in cats and it is much more likely that abdominal pain remains unidentified in veterinary species. Thus, the presence of abdominal pain should be assumed and analgesic drugs are indicated in all small animal patients with pancreatitis. Meperidine, butorphanol tartrate, morphine, fentanyl, or combinations of multiple analgesic drugs can be used in hospitalized patients. Outpatients can be treated with oral butorphanol, tramadol, or a fentanyl patch.

Antiemetics

Until recently the choices for antiemetic agents for use in dogs and cats with pancreatitis was limited. Metoclopramide, a dopamine inhibitor, was most widely used. However, it's effect on splanchnic perfusion remains in question and the author does not like to use metoclopramide in dogs or cats with pancreatitis. Fortunately, several other antiemetic agents have become available over the last few years. Dolasetron is a 5HT3 antagonist and is a very effective antiemetic agent in both dogs and cats. The injectable formulation of dolasetron can be used for intravenous, subcutaneous, and oral administration and is being used at 0.3-0.6 mg/kg q 12-24 hr in both dogs and cats. Recently, a new drug, maropitant, an NK1 antagonist has become available in both Europe and the US. Initial experiences in dogs are good, but there is little experience in cats and the drug is currently not licensed for use in cats.

Fresh frozen plasma

Studies in dogs suggest that when 2-macroglobulin, one of the scavenger proteins for activated proteases in serum, is depleted death ensues rapidly. Fresh frozen plasma (FFP) and fresh whole blood not only contain 2-macroglobulin, but also albumin, which has many beneficial effects in patients suffering from severe pancreatitis. In clinical trials in human patients with acute pancreatitis there was no benefit of plasma administration. However, FFP is widely believed to be useful in dogs with severe forms of pancreatitis.

Antibiotics

In contrast to human beings, infectious complications of pancreatitis are rare in dogs and cats with pancreatitis. Also, even though such complications occur frequently in human pancreatitis patients and are estimated to be responsible for approximately 25-50% of all deaths associated with acute pancreatitis, a clear advantage of antibiotic use has not been demonstrated to date. Therefore, the use of antibiotic agents should be limited to those cases when an infectious complication can be identified or is strongly suspected.

Antiinflammatory agents

There is no data on the use of anti-inflammatory agents in dogs and cats with severe pancreatitis, but no benefit was found in human patients with acute pancreatitis. In dogs and cats with severe pancreatitis corticosteroids should only be used in secondary cardiovascular shock. Corticosteroids may be needed to treat small animal patients with IBD and concurrent mild chronic pancreatitis, and do not appear to be harmful in these patients.

Other therapeutic strategies

Many other therapeutic strategies, such as the administration of trypsin-inhibitors (e.g. trasylol), platelet activating factor inhibitors (PAFANTs), dopamine, antacids, antisecretory agents (i.e. anticholinergics, calcitonin, glucagon, somatostatin), or selenium, and peritoneal lavage all have been evaluated in human patients with pancreatitis. With the exception of PAFANTs and selenium, none of these have shown any beneficial effect at this point. The efficacy of selenium, which has also been shown to decrease mortality in dogs with pancreatitis in an uncontrolled study, needs to be further evaluated before its use can be recommended. Also, dopamine has been shown to be useful in preventing progression of pancreatitis when administered within 12 hours of initiating pancreatitis. While this time-limit would preclude dopamine to be effective in routine therapy of pancreatitis, patients with pancreatitis that have to undergo anesthesia may benefit from treatment with dopamine during the procedure.

Mild chronic pancreatitis

It should also be noted that many patients, both canine and feline, have mild forms of chronic pancreatitis. Often times these patients have concurrent conditions, most notably IBD. Very little is known about appropriate therapy for these animals and management is often limited to evaluation and treatment of the concurrent condition, and careful monitoring of the pancreatitis. Serum calcium and triglyceride concentrations should always be evaluated in the patients in order to identify any risk factors that can potentially be addressed therapeutically. Also, the use of low fat diets is recommended in these patients. This is especially important in dogs where an ultra-low-fat diet should be chosen. Over the last two decades a new form of pancreatitis, autoimmune-mediated pancreatitis has been described in humans. Autoimmune-mediated pancreatitis is now commonly recognized in humans and is characterized by a lymphocytic-plasmacytic infiltration of the pancreas. Human patients with immune-mediated pancreatitis respond favorably to the administration of corticosteroids. Recently, several clinicians have started to cautiously treat canine and feline patients with chronic pancreatitis with corticosteroids and have found this treatment strategy to be beneficial in a portion of cases. In a recent pilot study the use of superoxide dismutase was shown to have a beneficial effect in dogs with subclinical chronic pancreatitis. Further studies are needed to confirm such a beneficial effect in dogs with more severe disease. Just as human patients with chronic pancreatitis, canine and feline patients with chronic pancreatitis are at risk for developing episodes of severe pancreatitis at any time or exocrine pancreatic insufficiency and Diabetes mellitus later in life.

Prognosis

The prognosis for dogs and cats with pancreatitis is directly related to disease severity, extent of pancreatic necrosis, occurrence of systemic and pancreatic complications, duration of the condition, and the presence of concurrent disease.