The pancreas is a gland within the abdomen located along the stomach and the first part of the small intestine that performs both endocrine and exocrine functions through the secretion of enzymes and hormones. The endocrine function of the pancreas includes the production of insulin, which is discharged into the blood in response to carbohydrate and protein ingestion. Insulin is responsible for taking sugars from the bloodstream and allowing the body’s cells to absorb these sugars. Diabetes involves the imbalance of insulin release into the body. The exocrine function involves the secretion of inactive digestive enzymes and bicarbonate into the intestine. These substances are released into the intestine, where they become activated and help break down consumed food so that nutrients may be absorbed in the intestines.
Pancreatitis refers to inflammation of the pancreas, and is caused by activation of the digestive enzymes within the pancreas itself due to pancreatic damage or blockage of its outflow duct. This results in pancreatic auto-digestion, whereby the enzymes destroy the pancreatic tissue. Acute pancreatitis is defined as reversible pancreatic inflammation, while permanent changes occur in the pancreatic tissue in chronic pancreatitis. These two forms of pancreatitis cannot be differentiated clinically, although clinical signs in acute pancreatitis are usually more severe than those seen with chronic pancreatitis. Acute pancreatitis can lead swiftly to systemic inflammation, shock, and death, and must be treated aggressively.
Cats can develop acute pancreatitis characterized by severe inflammation and systemic consequences similar to dogs (see our ExpertVet article on Acute Pancreatitis in Dogs). Acute pancreatitis in cats may be secondary to infectious diseases such as toxoplasmosis or may be idiopathic. However, the majority of cats that develop pancreatic inflammation have chronic pancreatitis instead of acute.
Chronic pancreatitis in cats is caused by immune-mediated inflammation within the pancreas. Cats are more prone to developing chronic pancreatitis rather than acute pancreatitis; as the cause of the inflammation is usually unknown, it is therefore referred to as “idiopathic” pancreatitis. It can be accompanied by inflammation of the gastrointestinal tract and inflammation within the liver. Some risk factors, however, have been documented, including trauma, toxins, parasites, and inflammation of other abdominal organs such as the liver and intestines. The combination of chronic pancreatitis, inflammatory bowel disease, and cholangiohepatitis is sometimes referred to as “triaditis.”
Clinical signs of chronic pancreatitis can be vague and non-specific. As with dogs, the diagnosis of chronic pancreatitis in cats can be elusive and is sometimes more difficult to diagnose than acute pancreatitis. A high index of suspicion is required to diagnose this syndrome in cats. Abdominal ultrasound can be helpful, however, in the literature, only 11 – 67% of cats with pancreatitis will have an abnormal-looking pancreas on an ultrasound. As diagnostic technology continues to improve, this percentage is likely to increase. These include intermittent, although occasionally severe, vomiting, loss of appetite, weight loss, fever, abdominal pain, and diarrhea. Bloodwork findings are non-specific and may include elevated white blood cell counts and elevated liver enzymes.
Unlike humans and dogs, cats with acute pancreatitis often do not have signs of vomiting and abdominal pain. In severe cases where there is systemic inflammation, the cat may have a low body temperature as well as low blood pressure, diarrhea, and labored breathing. In contrast, cats with mild but chronic pancreatitis may not show any clinical signs, or have vague signs such as loss of appetite, lethargy, dehydration, and weight loss.
Diagnostics that may be recommended include abdominal X-rays; ultrasound; bloodwork including a complete blood count and biochemical profile; urinalysis; urine culture; and a feline pancreatic lipase immunoreactivity test. X-rays are usually not very helpful in establishing a diagnosis of pancreatitis, but are important in ruling out other causes of disease.
Bloodwork can be normal or demonstrate diseases of other organ systems either unrelated to or caused by the pancreatitis. The fPLI test is a highly accurate test in diagnosing pancreatitis, detecting about 90% of cases; however, the presence of an abnormal fPLI test does not definitely mean pancreatitis is the sole cause of the clinical signs. Amylase and lipase, the routine pancreatic enzymes found as part of most routine laboratory panels, have been shown to not help in the diagnosis of pancreatitis in cats. The fPLI test then confirms the diagnosis and serves as a baseline to help assess response to therapy. This is an important concept, as resolution of the pancreatitis may not lead to resolution of the clinical signs.
Currently, the combination of the above tests is usually recommended to obtain a probable diagnosis of pancreatitis. The only definitive way to diagnose pancreatitis is to obtain a biopsy via surgery or laparoscopy, although many times the patient is too unstable to undergo anesthesia.
Treatment is truly helpful in nature; its aggressiveness depends on the severity of the pancreatitis. In severe cases, hospitalization is required for the restoration and maintenance of hydration; control of pain and vomiting; nutritional support; and possibly the administration of antibiotics. Unlike dogs and people, nutritional support is vital in cats as they can develop secondary liver disease within a few days of not eating.
If the patient is not vomiting and accepts food, it should be offered orally. Otherwise, the placement of a feeding tube is essential. If the patient is vomiting, a feeding tube that bypasses the region of the pancreas must be used.
In less severe chronic cases, hospitalization may not be required if the patient is hydrated and not vomiting. Nutritional support is essential, and placement of a feeding tube for home use (esophageal or gastrostomy) may be required. Appetite stimulants may assist help a cat with partial loss of appetite. The use of a low-fat diet, as typically recommended in dogs with pancreatitis, has not been proven to be essential in cats, so offering the cat anything they will eat is recommended.
The goal of therapy for feline chronic pancreatitis, once loss of appetite is addressed, is to suppress the abnormal inflammation within the pancreas. The drug of choice is the steroid prednisolone. Since steroids can have side effects (diabetes, congestive heart failure, and suppression of the immune system), an accurate diagnosis is necessary prior to the institution of steroid therapy.
The outlook is dependent on the severity of clinical signs, degree of pancreatic tissue damage, duration of illness, and the presence of a coexisting disease. In uncomplicated cases, if nutritional support is given early, there may be no future reappearance of disease. However, cats often develop chronic pancreatitis, which then can lead to persistent disease accompanied by vague clinical signs, as described above. As mentioned, an acute severe episode of pancreatitis can quickly lead to shock and death if aggressive treatment is not started promptly. Unfortunately, even with aggressive treatment, some patients may still die.
Because of the complexity in diagnosis and the unpredictability of response to treatment, suggesting a prognosis is difficult. In severe cases, hospitalization may be required for several weeks before the patient is stable enough to be discharged.
The outlook for chronic pancreatitis, in general, is quite good with the majority of patients doing well on steroid therapy. However, cats with chronic pancreatitis require therapy with steroids for the rest of their lives. In many cases, however, the drug can usually be tapered down to a low-dose daily or every-other-day therapy. The outlook can be worse if the cat is also suffering from inflammatory bowel disease or cholangiohepatitis, diseases which may require further work up with an endoscopy or a liver biopsy.