Treatment

Treatment of CP is largely symptomatic as in most cases there is no specific treatment, with the possible exception of the ECS. However, supportive treatment remains very important because it can make a real differ­ence to the quality of life of the affected dog and can be life-saving in acute exacerbations of underlying chronic disease.

Treatment of Ongoing Chronic Pancreatitis

CP in dogs and cats is usually a low grade, progressive, on-going disease that slowly destroys the pancreatic parenchyma, like a smoldering fire. It is important that the pain, progressive loss of endocrine and exo­crine function, and concurrent signs are managed.

In some cases of CP, the disease will even­tually ‘burn itself out' when the entire pan­creas has been destroyed. These cases will have functional loss (diabetes mellitus and EPI) but will no longer suffer from bouts of pain and acute exacerbations of disease. This is in many ways the “ideal” because the exo­crine and endocrine insufficiencies can be treated whereas the pain of on-going CP can be very difficult to control. It is impossible to predict in animals, as in humans, which cases of end-stage CP will “burn themselves out” in the animal's life time and which cases will continue to suffer from recurrent bouts of acute flare-ups of disease in spite of func­tional loss.

Pain can be particularly marked postpran- dially is often under-recognized by owners and clinicians, particularly in cats. Because of this, all animals with CP should be assumed to be suffering from pain until proven other­wise. Use of effective analgesics often results in behavior changes such as increased activ­ity and playfulness.

The pain of CP is similar to other chronic pain conditions in that it appears to cause up-regulation of central pain pathways with resultant hyperesthesia. There are many studies on the mechanisms and treatment of chronic pain in human CP but very little information in dogs and cats. The author has observed lymphocytic infiltrates within nerve sheathes on histology of the pancreas of affected dogs strongly suggesting that neu­rogenic pain is also important in small ani­mals with CP. Treatment recommendations are thus currently extrapolated from humans. The use of a ‘Pain Ladder' is the most helpful, starting with non-steroidals and then adding additional drugs until pain is effectively con­trolled (Figure 14.1). Traditional non-steroidals are often avoided because of the risk of GI ulceration and the frequency with which animals with CP have concurrent renal com­promise, particularly during acute exacerba­tions of disease. Consideration could be give to their use longer term when the animal is stabilized, with careful monitoring of renal

Figure 14.1 Analgesic ladder for dogs and cats with chronic pancreatitis, based on the human analgesic ladder in Sebastiano et al. (2005), which is based on the World Health Organization analgesic ladder for cancer pain. Note each step in the ladder can be added to the previous step for multimodal analgesia. *Preferred non-opioid drug in dogs, provided liver function is normal. Not to be used in cats. ^sNon-steroidal anti-inflammatories - higher risk of GI side effects in pancreatitis and only to be used when renal function is normal. ^Animals can be sent home with Fentanyl patches but great care must be taken about human contact particularly with children.

function. Acetaminophen is a useful first line drug in dogs, as in humans, but should never be used in dogs with decreased liver function or in cats. Feeding a low-fat diet is likely also to contribute to effective analgesia in dogs and cats with CP. In humans, high-fat diets increase postprandial pain and anecdotally the same is true in small animals.

The loss of exocrine function, together with recurrent bouts of anorexia, means that many affected dogs and cats can suffer from mild or more severe protein-calorie malnu­trition, which should be recognized and addressed. Clinicians should be proactive in supplementing pancreatic enzymes in these cases. In addition, it may be necessary to supplement cobalamin in dogs and particu­larly cats with EPI. This is traditionally given parenterally, but a recent study suggests oral supplementation may also be efficacious.

Comorbidities are common in canine and feline CP. Affected animals are often elderly, so some may be etiologically unrelated addi­tional diseases of ageing dogs and cats, which may impact on control of the CP. For exam­ple, hyperadrenocorticism in dogs appears to increase the risk of acute bouts of pancreati­tis. In cats, cholangitis and inflammatory bowel disease are common co-morbidities and their etiological relationship to CP is unclear. Clinicians should treat all co-morbidities as effectively as possible, while considering the potential for any treatments or dietary inter­ventions to worsen the pancreatitis.

CP in ECS may respond to immunosup­pression with corticosteroids or systemic cyclosporine. Ideally, diagnosis should be confirmed histologically in either pancreas or kidney prior to medication, but their use could be considered in an animal with convincing diagnostic imaging and clinic- pathological changes. Monitoring efficacy of treatment is currently challenging, as there are no validated blood tests for serial meas­urement, so animals should be monitored by clinical response.

Corticosteroids may also be indicated in cats with CP, predominantly to treat concur­rent inflammatory bowel disease and/or lymphocytic cholangitis. The underlying cause of these diseases in cats remains an area of active research and bacteria have also been implicated, so the concurrent use of antibiotics is logical in cats until the diseases are better understood. A more complete discussion of the potential etiolo­gies of CP and cholangitis in cats can be found in Simpson (2015)

Treatment of Low-Grade Recurrent Flare-ups

Dogs and cats with CP commonly present with stable ongoing chronic disease punctu­ated by episodes of acute exacerbation (like a smoldering fire which recurrently flares up). Severe acute episodes will require hospitali­zation and treatment. The owner at home can manage milder episodes, as long as the animal is not dehydrated or anorexic for a prolonged period of time. Mild acute epi­sodes should be managed with an increase in analgesic use and a day or two of fasting. Early enteral feeding is very important in the context of severe acute pancreatitis but in mild disease, a few days fasting is not injuri­ous and will reduce the pain associated with the episode. The author has also observed that some dogs respond to a course of metro­nidazole (10mg∕kg BID) after an acute bout of disease, particularly CKCS. This is likely to be due to development of secondary antibi­otic responsive diarrhea due to secondary small intestinal ileus and malabsorption.

Treatment of Acute Flare-ups

Acute exacerbations of disease may also be very severe. Cases presenting clinically as severe acute pancreatitis should be treated in the same way as truly acute pancreatitis with intensive supportive care. The pillars of treatment of acute pancreatitis, and acute flare-ups of chronic disease, are: fluid ther­apy, analgesia, anti-emetics, and early enteral feeding.