SLED DOG HEALTH: PANCREATITIS
Featured in the March/Aril 2006 issue of Mushing Magazine.©2006 Mushing MagazineTo understand pancreatitis, it helps to know a few things about this gland whose proper functioning is so essential to life. The pancreas is one of the largest glands in the body. It lies behind the stomach and the duodenum, the first part of the small intestine. Because of its long shape it also borders the liver, spleen and kidneys. Its main functions comprise the production of insulin to regulate sugar metabolism, and the production of digestive enzymes. The most important of these enzymes are protease, amylase and lipase, for the digestion of proteins, carbohydrates and fats, respectively. These potent enzymes are capable of digesting the pancreatic cells that make them, a process called autodigestion. To protect themselves from autodigestion in case the digestive enzymes accidentally get turned on, pancreatic cells produce enzymes in inactive form called zymogens, which are stored in membrane-bound sacks called zymogen granules. For additional protection, pancreatic cells also make enzyme inhibitors, which will attempt to deactivate digestive enzymes that may get activated prematurely, hopefully before cell damage occurs. In addition, the pancreas produces sodium bicarbonate to neutralize stomach acid, in order to prevent the highly caustic stomach fluid from damaging the intestine. Under normal conditions, digestive enzymes produced by the pancreas are activated when they reach the small intestine. However, in pancreatitis, a painful and life threatening inflammation of the pancreas, these enzymes are activated prematurely (before leaving the pancreas), and before the protective enzymes and enzyme inhibitors can act, leading to autodigestion of the gland and possibly surrounding organs.Among the possible causes of pancreatitis are certain medications, i.e., steroids, food-borne toxins, metabolic disorders, i.e., hyperlipidemia (abnormally high levels of fat in the blood), trauma and shock. There are two types of pancreatitis – the acute form and the chronic form. Dogs may contract pancreatitis at any age, however, they are believed to be more susceptible after reaching middle age (seven years). Females seem to be more susceptible to the disease than males. Diabetic dogs are believed to be more at risk for pancreatitis, and are more difficult to treat.Although theories about what really triggers pancreatitis in dogs abound, a definite cause has never been established. Certainly, dogs on a high-fat diet are thought to be more likely to have an attack than do dogs eating a low-fat diet. The high-fat theory is supported by the fact that an attack of pancreatitis often follows a fatty meal. However, some experts, including two popular sled dog veterinarians, do not believe that the high-fat diet causes pancreatitis in working sled dogs. According to Mark May, DVM, of Golden Heart Veterinary Services in Fairbanks, Alaska, “Pancreatitis is not an issue in active working sled dogs in my experience. When they retire and are adopted out, spayed or neutered, they tend to obesity, which is a risk factor.”Sharon Brunslick, DVM, of the Antigo Veterinary Clinic, Antigo, Wisconsin, says, “I haven’t seen pancreatitis in any working sled dog. My feeling is that these athletes are utilizing the fat calories. The high-fat diet does not appear to adversely affect them as long as they are burning it off. That’s not to say that the couch potato pet husky could safely consume a diet high in fat.”Figures on the incidence of pancreatitis are hard to obtain, since the symptoms of the disease mimic other gastrointestinal diseases, i.e., acute gastroenteritis, flare-ups of inflammatory bowel disease, intestinal obstruction. Therefore it is believed that many cases of pancreatitis go undiagnosed. Symptoms of acute pancreatitis, which may come on suddenly and severely, include abdominal pain shown by a hunched up back, abdominal distention, anorexia (lack of appetite), vomiting and diarrhea leading to dehydration. The stools are yellow and greasy looking. An irregular heart rhythm (arrhythmia) and difficulty breathing may develop as the condition increases in severity, progressing to a life-threatening condition called disseminated intravascular coagulation (DIC), accompanied by multiple hemorrhages. Neighboring organs, such as the liver, kidneys, and intestines, may become inflamed due to the release of pancreatic enzymes from the damaged pancreas. This could result in permanent damage to these organs, or acute kidney failure. It could also lead to peritonitis, a life-threatening general inflammation of the abdominal cavity. The diagnosis of pancreatitis is established by means of physical examination and the symptoms observed by the owner, as well as the measurement of the pancreatic enzyme amylase (starch digestion) and lipase (fat digestion) in the blood. These enzymes are usually elevated in pancreatitis, although normal levels do not rule out the condition. Other blood parameters include liver enzymes, which may be increased if that organ is affected. A CBC (complete blood count) will show a high white cell count. Pancreatitis usually leads to a decrease in blood calcium, but this occurs in several other conditions as well. Another test called serum trypsin-like immunoreactivity may be of help in the diagnosis, as well as X-rays or ultrasound. A biopsy may confirm the diagnosis, but this procedure is not commonly performed. Since none of the tests are 100 percent reliable, veterinarians sometimes make a presumptive diagnosis of pancreatitis based on medical history and symptoms, so that a sick dog can be promptly treated.The first step in treatment is complete rest of the pancreas, by withholding food, water and oral medications for a minimum of 24 hours, which stops the production of digestive enzymes, in order to prevent the gland from digesting itself. Intravenous or subcutaneous fluids are administered to replace electrolytes and other nutrients, and to fight dehydration caused by vomiting and diarrhea. After vomiting has stopped, the dog is fed small amounts of a bland, easily digestible diet low in fat. Cooked rice, cottage cheese and boiled eggs plus supplements are excellent choices for this condition. Depending on the progress, the volume of food can be slowly increased, while the dog remains on the special diet, possibly for life. If the progress is good, it is nevertheless possible that the dog’s regular diet can eventually be reintroduced.The urine output should be monitored by placement of a urinary catheter. Antibiotics are usually administered to combat secondary infection of inflamed pancreatic tissue. If pain is severe, analgesics, i.e., meperidine, may also be administered. Vomiting may be relieved by means of administration of cimetidine, loperamide or metoclopramide. If the animal is in shock, intravenous corticosteroids may be necessary. To reduce pancreatic fluid secretion, anticholinergic agents (i.e., atropine sulfate, Darbazine) may be administered. If the cause of the pancreatitis is a toxin or medication, these need to be discontinued. Surgery may be required in rare cases where a pancreatic abscess develops, if a patient is unresponsive to medical management of pancreatitis, or if shock can not be reversed. This is considered high-risk surgery. Surgical procedures include pancreatectomy, a partial or total excision of the pancreas, peritoneal drainage for pancreatic abscessation or following pancreatectomy, or peritoneal lavage in a patient with acute hemorrhagic necrotic (necrosis = death of tissue) pancreatitis with resultant generalized peritonitis. Although the disease can be unpredictable, in mild cases the chances of recovery are good, especially following a first episode of pancreatitis. In many instances a diet low in fat and somewhat low in protein is all that is needed to prevent a recurrence or complications. Yet some dogs, especially those with severe pancreatitis, may experience a recurrence, sometimes leading to fatal complications, even after successful completion of therapy of the initial episode. Obese or diabetic dogs, as well as those with hypothyroidism, gastrointestinal disease or epilepsy have a higher risk of developing fatal complications. Some animals may develop the chronic form of the disease, which is manifested as pancreatic insufficiency, in other words, the absence of digestive enzymes. This condition is also called maldigestion syndrome. The stools are voluminous and pale, and greasy soiling may be seen around the rectum. A damaged pancreas due to one episode of severe pancreatitis or several milder ones may also lead to diabetes mellitus.Dogs with pancreatic insufficiency can not absorb the nutrients from food, passing them in the feces in undigested form. These patients usually exhibit a ravenous appetite, persistent diarrhea and weight loss. They can starve to death unless pancreatic enzymes are replaced. Replacement of pancreatic enzymes in the diet is necessary for the rest of the dog’s life. The veterinarian will most likely recommend a special diet and nutritional supplements. With this regimen, plus periodic repetition of the blood tests, the quality of life of these dogs will be good, and they can live out their normal lifespan. Karen Gadke, Ph.D. (Health Science) is a clinical study specialist, medical writer, author and lecturer. She has been mushing/racing since 1979. She owns both Siberians and Alaskans.