Most people have heard of the pancreas but aren’t really sure what it is.
Pancreatitis in the cat
Illustration courtesy of Wendy Brooks, DVM
Pancreas close up
Illustration courtesy of Wendy Brooks, DVM
The pancreas is a pale pink glandular organ nestled just under the stomach. It has two main functions: handling the digestive enzymes needed to break down our food and making hormones to regulate metabolism. When it comes to pancreatitis (inflammation of the pancreas), we are going to focus on the digestive enzymes. Digestive enzymes are powerful and readily break down the fats and proteins that we eat so that we can absorb them into our bodies properly. So how is it that we can store these enzymes without digesting our own selves? It turns out we have safeguards. Normally, digestive enzymes are made and stored in inactive forms within special biochemical sacs where they cannot hurt us. They are released down a special duct (called the "pancreatic duct"), which delivers them into the intestine, where they can work on the food eaten. The digestive enzymes are not activated until they reach the intestine and meet the acidified food coming out of the stomach. They activate when they meet other enzymes secreted in the intestine in response to food presence or by the food presence itself. All this adds up to a beautiful strategy for obtaining nutrients safely.
Pancreatitis has the potential to be a serious condition. Here's why:
As mentioned, the normal pancreas has a number of safeguards in place to keep its digestive enyzmes securely stored in a safe state.
If these enzymes escape and become active, they will digest the body. This is exactly what happens when the pancreas gets inflamed: the enzymes escape, become inappropriately activated, and begin digesting the pancreas itself. The living tissue becomes further inflamed, and the tissue damage quickly involves the adjacent liver. Toxins released from this rampage of tissue destruction are released into the circulation and can cause a body-wide inflammatory response. If the pancreas is affected enough to disrupt its ability to produce insulin, diabetes mellitus can result; this can be either temporary or permanent. It is also possible to develop exocrine pancreatic insufficiency (EPI) following pancreatitis.
Complications
Certain complications associated with pancreatitis include disrupting surfactants in the lung tissue that normally keep the tiny air-filled alveoli from collapsing after each exhaled breath. Without surfactants, the alveoli close up, and respiratory failure results.
In addition, fats throughout the body are destroyed in an event called the Weber-Christian syndrome. This is an inflammatory condition where the fat layer under the skin forms nodules that can lead to ulcers and openings on the top layer above them. This is also known as nodular panniculitis.
Pancreatitis is one of the chief risk factors for the development of what is called disseminated intravascular coagulation, or DIC, which is basically a massive uncoupling of normal blood clotting and clot-dissolving mechanisms. This leads to abnormal simultaneous bleeding and clotting of blood throughout the body.
Pancreatic encephalopathy (brain damage) can occur if the fats protecting the central nervous system become digested.
Fortunately, serious complications such as the above are rare but be aware that the potential for such conditions exists should the pancreatic inflammation become severe. Most of the time, pancreatitis is confined to the area of the liver and pancreas.
Pancreatitis can be acute or chronic with the chronic form more common (acute cases can reverse completely).
Pancreatitis can be mild or severe. Acute cases tend to be more severe and chronic cases tend to be milder. Mild cases may require little to no treatment.
What Causes Pancreatitis in Cats?
Unfortunately, 90% of the time, we never find out. We have some idea of possible risk factors, though.
Chances are the cause of pancreatitis for a given patient will never be determined.
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If Your Cat Has Pancreatitis, What Might You Observe at Home?
In dogs and humans, this condition is associated with significant nausea and abdominal pain. According to one recent study in cats, though, only 35% of cats with pancreatitis showed vomiting, and only 25% appeared to have abdominal pain. A fever is a possible sign, but often, the temperature will drop instead. Lethargy and appetite loss are consistent signs. Nearly all cats with pancreatitis lose their appetites, and about half of them will have been affected long enough to show weight loss.
Approximately 40% of cats with hepatic lipidosis have pancreatitis as the underlying cause. Hepatic lipidosis represents a specific type of liver failure that stems from appetite loss/inadequate calorie intake and complicates pancreatitis tremendously.
Making the Diagnosis
The diagnosis of pancreatitis can be a challenging one, especially in chronic pancreatitis. All laboratory information and imaging, as well as clinical information, should be integrated. The diagnostic process has been aided by the development of the SPEC-FPL and PSL tests, which stand for Specific Feline Pancreatic Lipase and Pancreatic Sensitive Lipase respectively. The SPEC-FPL test can be run as an in-house test kit that yields a positive or negative or even a numeric value, depending on the equipment used in a matter of minutes. The PrecisionPSL® test can be run by reference labs but does not have an in-house test kit.
These tests are based on the PLI test, which stands for Pancreatic Lipase Immunoreactivity, a test available through most veterinary hospitals. Lipase is one of the pancreatic digestive enzymes, and small traces of it are normally in circulation. These levels increase dramatically during pancreatitis, and thus, the diagnosis can be made noninvasively without the expense of ultrasound. This form of testing is actually more sensitive than ultrasound, which means it can detect pancreatitis in a milder state.
Of course, acute pancreatitis can be diagnosed on ultrasound because the inflamed pancreas becomes swollen and exhibits texture changes typical of inflammation. Chronic pancreatitis has more subtle sonographic findings. Assessing the pancreas sonographically, however, depends on the operator's skill. Pancreatitis can also be diagnosed by biopsy during surgical exploration as well, though there is controversy as to whether removing a piece of the pancreas generates additional inflammation. The advantage of surgical exploration, however, is that other organs can be sampled to get a more complete picture of what is happening in the abdomen.
The SPEC-FPL and PrecisionPSL tests have become common additions to basic feline blood work and their elevations are commonly seen in cats with no symptoms of any kind. The significance of this suggests (but does not necessarily confirm) that the cat has an unhealthy bowel population, which has overgrown, and is either elaborating material that is inflaming the pancreas or has invaded the pancreas. If the cat genuinely has no symptoms, treatment is not necessary; however, it may be prudent to consider a hypoallergenic diet or the addition of probiotics (live cultures of beneficial bacteria) to the food to assist in recolonizing the bowel into a healthier microbe community.
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How is the Cat Treated?
There are three parts to treatment: removing the cause of pancreatitis (this is usually not possible since the cause is only rarely known), general support and symptomatic relief through the inflammatory crisis, and monitoring and instituting protection against the serious complications listed above. Intravenous fluid therapy is used to support the pancreatic vasculature and combat any dehydration from vomiting or diarrhea. This simple act of perfusing the pancreas enables damaging inflammatory biochemicals to be flushed away and healing to begin.
Medications are used to control pain and nausea. In the dog, high-fat diets are important predisposing factors for pancreatitis but this appears not to be true for cats. Pre-existing inflammatory bowel disease seems to bear more feline relevance so treatment in that direction seems more appropriate (steroids, antacids, low residue diets, or hypoallergenic diets). Anecdotally, digestive enzyme supplementations are felt to be helpful in some cases. In the past, food restriction was included in treatment to rest the sensitive pancreas but newer thinking is that the entire GI tract heals faster when food is passing through it. Nutritional support is important in cats so that hepatic lipidosis does not develop.
Vitamin B12: Deficiency is Common
The healthy pancreas manufactures a substance called intrinsic factor that is necessary for the absorption of vitamin B12 (cobalamin) from the diet. The unhealthy pancreas does not make enough intrinsic factor, and deficiency ensues when pancreatitis becomes chronic. This leads to an unthrifty and often anemic cat. Since dietary B12 cannot be absorbed without intrinsic factor, the traditional solution is to provide B12 by injection, usually at home, once or twice a week, and periodically thereafter. Vitamin B12 levels can be tested to determine if supplements are needed or, since the injections are relatively inexpensive and have a broad safety margin, sometimes they are simply prescribed without testing. A new oral B12 supplement has become available recently; its manufacturer claims to have solved the intestinal absorption problem.
Prognosis
In the long run, the cat's health depends on how severely ill it is and what accompanying conditions exist. If the cat survives the episode of acute pancreatitis, there is a good chance that he or she will live a normal life thereafter. However, chronic cases of pancreatitis may wax and wane for years, requiring a permanent diet change and chronic medication administration.
In Summary
- Pancreatitis is inflammation of the pancreas. The pancreas secretes digestive enzymes that break down nutrients.
- If digestive enzymes are activated too early, they can digest the body itself instead of food.
- It can be painful and life-threatening as well as acute or chronic, mild or severe.
- Signs include appetite loss, vomiting, diarrhea, a painful abdomen, and fever.
- Certain additional problems can occur, such as affecting the lung to the point of respiratory failure.
- In most cases the cause is unknown but these issues can be associated with: biliary-pancreatic reflux, possibly certain drugs, trauma, pancreatic tumor, or obesity.
- Diagnosis is generally made with lab tests. Ultrasound is more useful than radiographs. Sometimes surgery is the only way to diagnose it.
- Treatment often involves IV fluid support or possible sub-cutaneous fluids for mildly affected patients. Length of hospitalization varies and some cats may require a number of days or even a week in the hospital. Pain and anti-nausea medications are needed.
- When 80% of the pancreas is damaged and insulin cannot be produced, diabetes results.
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