Veterinarians continue to search for more reliable diagnostic tests and prognostic indicators for feline pancreatitis. Unfortunately, pancreatitis symptoms in cats are often vague, and blood tests and ultrasound imaging results are not yet consistent enough to rely on for a definitive diagnosis.
This leaves the veterinarian to determine whether pancreatitis is the likeliest diagnosis and then to evaluate the seriousness of the case.
Two recent papers in the Journal of the American Veterinary Medical Association, one in 2013 and one in 2014, looked at these issues. The 2013 paper focused on symptoms and test results most consistently linked with severe disease and a lower likelihood of the cat surviving. The second reviewed two blood tests and ultrasound imaging to try to determine which, if any of them, most accurately diagnosed pancreatitis.
What the Pancreas Does and How Pancreatitis Affects The Body
The pancreas has two separate functions. First, it produces two hormones insulin and glucagon, which are released into the bloodstream. When this process is faulty, diabetes mellitus is a common result.
The other function of the pancreas is to release enzymes that assist in digesting fats, proteins and carbohydrates. When these digestive enzymes start working before they leave the pancreas, they cause damage to that organ, resulting in inflammation, bleeding, edema and tissue destruction.
As the disease progresses pancreatitis causes damage throughout the body. In the worst cases cats develop kidney or respiratory failure, disseminated intravascular coagulation where the balance between the factors that start and stop coagulation is disrupted, or even multiple organ failure.
The Difficulty in Diagnosing Pancreatitis in Cats
There is often no obvious cause for feline pancreatitis and its most common symptoms are lethargy, dehydration and lack of appetite, all of which are seen in numerous other diseases. Unlike human pancreatitis cases who experience significant abdominal pain, surprisingly, most animals don’t. To make things more complicated, cats who develop pancreatitis often have other health problems such as toxoplasmosis, feline infectious peritonitis or diabetes which complicate the diagnosis.
Diagnostic tools used to determine whether pancreatitis is the culprit include radiographs, abdominal ultrasound and standard blood tests. Vets may also measure feline pancreatic lipase immunoreactivity (fPLI) or 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6’methylresorufin) ester (DGGR).
Doctors will evaluate these tests together with the physical examination. None of these tests are diagnostic for pancreatitis. Instead they are used to rule out other diseases or physical causes for the symptoms the cat is experiencing, and to get an overall picture of the animal’s condition.
In the 2014 study, the specialized blood tests appeared to more consistently agree with clinical findings (the combination of patient history, physical examination, routine blood tests and radiographs). Unfortunately, when different people produce and review radiographs and ultrasound images may result in inconsistent interpretation of those images.
As a result, radiographs and ultrasonography are more valuable in ruling out other reasons for the symptoms at present. The two specialized tests that measure enzyme activity were generally in agreement. The DGGR test is the norm in Europe, while in the US fPLI is the standard test.
Given that the 2014 study was retrospective, reviewing cases rather than setting up a specific study to use each diagnostic test and compare results, there are limitations.
The authors quite rightly state that the only way to really determine the value of ultrasound would be to do the ultrasound examination followed by a complete histopathologic examination of the pancreas after euthanizing the animal, and a study such as that would not be ethically justified.
How Feline Pancreatitis is Treated and the Limitations of Those Treatments
Once other possible causes are ruled out the veterinarian will generally begin treatment based on the probability that it is pancreatitis. The treatment is non-specific, using supportive care to ease the symptoms the cat is experiencing. This generally includes fluid therapy to counteract any dehydration, providing nutrition via a stomach tube or intravenously, and giving drugs to control pain and vomiting. The drugs are considered useful even in cases where there is no vomiting, as the cat may have nausea and discomfort that is not obvious.
It would seem logical that when symptoms are mild, a cat would be likely to recover. Unfortunately mild symptoms do not always mean that the damage to the pancreas is limited. And, even in cases where symptoms are significant, there is great variability in the course of the disease. Some cats respond well to supportive care and recover. Others take a sudden turn for the worse and do not survive.
The 2013 study suggests that a cat having difficulty breathing, with high blood potassium and fPLI levels on admission, is at greatest risk of not surviving. One major limitation of that study was that each cat was treated individually, according to its symptoms and any other health issues. This means that the effects of the various treatment regimes are not well known.
Another study reviewing success rates of various treatment protocols would help put all the pieces together. In the meantime, these three symptoms may at least provide some guidance for owners in their decision making process.
What This Information Means to Cat Owners
Once a cat owner understands the difficulty in diagnosing this disease and making an accurate prognosis in the individual case, he or she will be better equipped to talk to their veterinarian about their own cat, taking into account other health issues which may have an impact on the case and discuss options based on the individual cat’s situation. For example, the level of stress an individual cat experiences at the veterinary hospital will also have an effect on prognosis.
Most cat owners want to do everything they can to help their cat get better but few want their pet to suffer. Particularly in the case of severe pancreatitis, with its guarded prognosis, awareness of the potentially very sudden changes in condition even when the cat has not initially seemed very ill may help in the deciding what level of treatment is best.