The pancreas lives in the cranial abdomen close to the stomach and duodenum. With a right and left limb, this organ plays both endocrine and exocrine roles and is vital to nutritional function. The pancreas secretes glucagon and insulin vital to glucose regulation, but also secretes digestive enzymes into the duodenum to assist with the breakdown of the carbohydrates, lipids and proteins ingested with each meal. Problems with the pancreas can lead to catastrophic problems with our patients, namely diabetes and the dreaded pancreatitis. Pancreatitis can be an acute or chronic condition; it can be mild or severe. In some cases the animal may show no clinical signs at all and recover well, many hospitalized patients will make a complete recovery with proper supportive care, but the cascade of inflammation in severe cases can cause death.
Pancreatitis is, simply put, inflammation of the pancreas. But this condition is anything but simple. Animals suffering from acute pancreatitis can end up being some of the more critical patients to treat. In many cases the exact cause of pancreatitis is unknown, but in dogs can be linked to hyperlipidemia, obesity, a low protein high fat diet, dietary indiscretion, the use of some drugs (potassium bromide, Lasparaginase), trauma, and hypoperfusion. There is some breed predisposition in the case of Miniature Schnauzers, terriers, and Miniature Poodles. In cats, FIP and Toxoplasmosis can be linked to pancreatitis but in many felines, a direct cause cannot be determined. Whatever the cause, large amounts of the digestive enzymes stored in the pancreas are inappropriately released, and the pancreas begins to autodigest itself. It is important to note that the inappropriate activation of these cells happens inside the pancreas and is not necessarily changed by adding or removing food from the patient. Digestive enzymes, now in high numbers in systemic circulation, begin to cause inflammation on a grand scale and can tip the patient into SIRS and cause other organ systems to fail.
In both dogs and cats, the clinical signs of pancreatitis are non-specific but will increase with the severity of the disease. In dogs, most will experience anorexia, vomiting, weakness, and abdominal pain. A lack of any one of these clinical signs should not rule out pancreatitis, and it should be suspected in any dog presenting for non-specific GI distress. In cats, the clinical signs of pancreatitis are even less specific, mainly anorexia and lethargy. Most cats, even with severe pancreatitis, will not present with vomiting or abdominal pain.
Diagnostics in pancreatitis begin with ruling out the causes of anorexia, vomiting and abdominal pain. CBC and chemistry panel results are usually not helpful in the diagnosis of pancreatitis, but can help to rule out other disease processes. While it is common to see elevated serum lipase and amylase levels in dogs with pancreatitis, these enzymes are neither sensitive nor specific enough to use as a diagnostic tool. There are many cells in the body that will secrete lipase, and elevated lipase levels can be seen in renal disease, hepatic disease, some cancers, and sepsis. Likewise, amylase is a non-specific enzyme that can be elevated in a variety of organ disorders, and even remain normal in dogs with documented pancreatitis. Due to the location of the pancreatic and bile duct, patients with severe inflammation of the pancreas may present with elevated hepatic enzymes, mainly total bilirubin. The pancreatic inflammation can cause cholecystits and the resulting hyperbilirubinemia and icterus. This is more common in cats.
Radiographs should be obtained in suspected pancreatitis patients to rule out a GI foreign body but are nonspecific in diagnosing the disease. In severe enough canine cases, abdominal radiographs may display decreased detail in the cranial abdomen and a shifting of the duodenum to the right, but these are subjective findings and not always discernable. In cats, abdominal radiographs often hold no keys to diagnosing pancreatitis. Abdominal ultrasound is a much more sensitive diagnostic tool for pancreatitis in both dogs and cats, and remains the standard for imaging. An added benefit of using abdominal ultrasound is being able to detect any cysts, abscesses, or masses that are contributing to pancreatitis. Cats, as they tend to be, present more of a diagnostic challenge with ultrasound, but in the hands of an experienced radiologist a definitive diagnosis is often made.
Pancreatic lipase immunoreactivity (cPLI for dogs, fPLI for cats) measurements as outside laboratory tests have become available. This test is specifically measuring the lipase originating from the exocrine pancreas. More recently, the ability to measure canine pancreas-specific lipase (Spec cPL) and feline pancreas-specific lipase (Spec fPL) has become available. These tests are highly specific and highly sensitive blood tests available for diagnosing pancreatitis, especially with any lack of ultrasonic evidence. SNAP tests for Spec cPL and Spec fPL are available for in-house use as bedside diagnostics. While a diagnosis of pancreatitis is important when communicating expectations and hospital time to the owner, treatment for the disease is supportive and aimed at maintaining perfusion, providing pain management, and starting nutrition supplementation as soon as possible. Most canine patients with pancreatitis present to the hospital because they are vomiting and lethargic, both canines and felines are often dehydrated. Because of the acute systemic inflammation caused by pancreatitis, hypotension is a common clinical finding and must be corrected with IV crystalloids and often colloids. Tissue perfusion is necessary for healing, and maintaining a normal blood pressure is important to therapy in these patients. Electrolyte disturbances can occur and should be monitored and corrected as treatment continues.
Pancreatitis is known to be a painful condition in people, and indeed many canine patients present with abdominal pain. Even if the patient is not showing outward signs of pain, pain management must be considered in hospitalized pancreatitis patients. Opioids (oxymorphone, hydromorphone) are used at the beginning of treatment and severe cases may need a CRI (fentanyl) to properly manage pain. Close monitoring is necessary to determine pain, and mild cases may do well with oral pain management at home. Serial measurement of Spec PL can be performed, as well as serial ultrasounds, to measure improvement and help guide pain management for individual patients. Nutrition should not be overlooked in patients with pancreatitis. It was once thought that pancreatitis patients should be fasted, as this would reduce the secretion of digestive enzymes and lead to reduction in inflammation. Now we know this is absolutely not the case and we need to be aggressive with nutritional support in these patients. It is now thought that pancreatitis is caused by the intracellular activation of enzymes, and not stimulation of the pancreas itself. Therefore feeding or withholding nutrition will not change this process. Not feeding a patient, especially a critically ill patient, can result in a breakdown of the gut mucosal barrier and lead to bacterial translocation. Nutrition, proteins, and energy are required for healing and should be started as soon as possible. Ensure the patient is appropriately fluid resuscitated prior to introducing nutrition, as gut perfusion is necessary. Monitoring perfusion in these patients is ongoing and fluid therapy important to their care.
In human studies of pancreatitis, enteral nutrition is safe and well tolerated by patients. It is a more simple way to administer nutrition and requires less monitoring compared to IV nutrition. The ability to feed enterocytes is the main advantage of enteral nutrition and is a major benefit to the patient. Early introduction of nutrition has been associated with earlier return of intestinal motility. Even trickle feeding (feeding far less than RER but enough to provide some nutrition) is helpful until the patient can tolerate larger amounts of food. As soon as vomiting ceases, a nasoesophageal or nasogastric tube can be placed and nutrition started. These tubes are simple to place in any hospital setting and are generally well tolerated by the patient. Once the patient has recovered from sedation necessary to place the feeding tube, begin feeding a liquid diet at ¼ RER. Gradually increase the amount fed over the next 48- 72 hours until full RER is reached.
It is best to attempt to feed dogs with pancreatitis a low fat diet if possible. However, liquid diets currently available for animals typically have a high fat content. Cats tend to do well with these high fat solutions. If you have a dog with confirmed hyperlipidemia and have concern about feeding such a high fat food, an esophagostomy tube or gastrostomy tube can be placed. With these tubes, commercial canned diets can be blended and fed, and the diet can be tailored to the patient (ie: low fat).
Many of these patients need close monitoring of nausea and treatment as needed. Ondansetron (0.1- 0.2mg/kg q6-8hr IV) and dolansetron (1.0mg/kg q24h IV) suppresses vomiting receptors in the vagus nerve and in the brain and can help with nausea. Maropitant (1mg/kg q24h SC) works against neurotransmitters to suppress vomiting. Even with a feeding tube in place, food can be offered and these patients encouraged to eat on their own.
Patients with mild pancreatitis may recover within a short period of time and may need little intervention from the hospital staff. However, severe pancreatitis can lead to critical illness. Acute pancreatitis leads to widespread circulation of digestive enzymes which trigger widespread inflammation throughout the body. This pro-inflammatory state can activate the clotting cascade, cause platelet sludging, ischemia, vasodilation and profound shock.
Systemic Inflammatory Response Syndrome is the body’s response to an inflammatory focus and is characterized by any or all of the following:
• Tachycardia (HR >120bpm in dogs; >225, 20 dogs: >40 cats)
• Tachypnea (RR >20 dogs: >40 cats)
• Temperature (temp >103.5°F, < 100°F dogs and cats)
• WBC (>16k, 19.5k, < 5k cats)
Any pancreatitis patient who fits the above criteria should be closely monitored for clotting abnormalities and hypotension. Cats especially can develop pulmonary edema and effusion when they develop SIRS due to an increase in vessel permeability. This carries a poor prognosis for these patients. Fresh frozen plasma may be required to treat any clotting abnormalities. Plasma has the added benefit of providing protein to the patient, although not recommended for treatment of pancreatitis alone, only in cases of SIRS and clotting abnormalities.
Patients with severe pancreatitis are at an increased risk for developing either transient or permanent diabetes mellitus. Monitor the blood glucose in severe cases and tailor insulin therapy as needed, understanding that the patient may have waxing and waning insulin needs. Due to the proximity of the pancreas, bile duct, and liver, some patients may develop a cholangiohepatitis and you may see elevations in hepatic values. While pancreatitis itself is not often treated with antibiotics, in patients who develop other organ dysfunction antibiotics may be required. Closely monitor blood chemistry values and mucous membrane color.
With close monitoring, an understanding of the risks of developing SIRS and MODS, and early nutritional intervention, many pancreatitis patients can make a full recovery. However, it is possible that even with the best care these patients can die of this disease. Owner education, proper diet, and prompt treatment can all play a role in improving the chances of your next pancreatitis patient making it home.
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