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Acute Pancreatitis in Dogs
Pancreatitis is defined as inflammation of the pancreas. The vast majority of cases are a result of sterile inflammation although secondary infections of the pancreas can occur. The normal function of the pancreas is production of insulin and digestive enzymes. When pancreatitis occurs, the digestive enzymes are released locally into the pancreatic tissue and the surrounding tissues within the abdominal cavity. Additionally, some of these digestive enzymes and other factors are released systemically into the bloodstream. Normally, there are a series of inherent defense mechanisms that prevent this from occurring, however, these become overwhelmed once pancreatitis develops.
The most common cause of pancreatitis in dogs is the ingestion of a meal high in fat. This can be a one-time occurrence due to a dietary indiscretion or be a cumulative development in at-risk individuals. Concurrent diseases such as hyperlipidemia (high serum triglycerides) may predispose individuals to pancreatitis.
Clinical signs of pancreatitis include inappetence, lethargy, fever, abdominal pain, vomiting and diarrhea. Systemic manifestations such as systemic inflammatory response syndrome may lead to multiple life-threatening complications within the lungs, clotting system, and liver and kidneys. Labwork findings include elevated white blood cell counts, elevated liver enzymes, electrolyte abnormalities from vomiting, and an array of other non-specific abnormalities.
Diagnosis of pancreatitis can be difficult as no one test is definitive. History, clinical signs, and physical examination findings help the doctor to develop an index of suspicion for pancreatitis. Labwork findings as above help to narrow the differential list. Unfortunately, the common pancreatic enzymes on routine labwork, amylase and lipase, are only approximately 50% sensitive and specific for pancreatitis in dogs. Therefore, to confirm the diagnosis, imaging of the pancreas with ultrasound is recommended. Ultrasound has been reported to be approximately 70% sensitive for detecting an abnormal-appearing pancreas in the dog. In our experience, the sensitivity is probably a bit higher. Confirmation with a blood test called canine pancreatic lipase immunoreactivity (CPLI) is recommended as this test is thought to be approximately 90% sensitive and specific.
Treatment of pancreatitis should be aggressive as life-threatening consequences can occur rapidly. The sooner therapy is instituted, the more likely a complete recovery can be made. Intravenous fluid therapy is used to treat and prevent dehydration, support the kidneys, and address and prevent electrolyte imbalances. Dopamine or dobutamine, medications delivered intravenously as a constant rate infusion, help raise blood pressure and may help to stimulate blood flow to the pancreas increasing the ability of the pancreas to heal. Intravenous antibiotics are used to prevent bacterial translocation of the normal gastrointestinal flora into the bloodstream. Fresh frozen plasma is recommended to supply clotting factors and provide the “anti-enzymes” (normal defense mechanisms) overwhelmed by the pancreatic inflammation. Anti-nausea medication and antacid therapy is used to help the patient feel better and pain medication is used because our pets have a hard time telling us when they hurt.
Prognosis for pancreatitis improves with diligent, immediate care and depends upon the number of complications the patient presents with or develops despite appropriate care. Long-term fat restricted diets are recommended for patients developing pancreatitis to prevent recurrence. Recurrent episodes of acute pancreatitis may occur without strict adherence to dietary recommendations.
Causes and Diagnosis of Cushings Disease in Dogs
Cushings disease or hyperadrenocorticism is a common endocrine (glandular) disease in dogs. Cushings disease results from excess production of a hormone called cortisol by the adrenal glands. This handout will cover adrenal function in normal dogs and causes, clinical signs, and diagnosis of Cushings disease.
Normal Adrenal Function
Cushings disease results from overproduction of a hormone called cortisol by the adrenal gland. The clinical signs noted are directly caused by excess cortisol. Indeed, normal dogs receiving steroid medications can develop the exact same clinical signs noted in dogs affected with Cushings disease.
Cortisol production by the adrenal glands in normal dogs is controlled by the pituitary gland. The pituitary gland is located at the base of the brain and is also called the master gland. The pituitary gland produces ACTH which stimulates the adrenal glands to produce cortisol. Cortisol levels in the blood are detected by the pituitary gland. When blood levels are adequate, the pituitary gland decreases ACTH release and adrenal cortisol production decreases. This process serves to prevent insures that there are adequate, but not excess cortisol levels in the blood. This system is analogous to a home heating system where the thermostat (analogous to the pituitary) senses air temperature (analogous to cortisol level) to control the furnace (analogous to adrenal glands) to insure adequate but not excessive heating. Control of the adrenal glands in normal dogs is summarized below:
Causes of Cushings Disease in Dogs
There are two causes of Cushings disease in dogs, Pituitary Dependent Hyperadrenocorticism and Adrenal Tumor Hyperadrenocorticism.
Pituitary Dependent Hyperadrenocorticism
In about 90% of cases, excess production of ACTH by the adrenal gland causes elevated cortisol production by the adrenal glands to cause clinical signs. This type of Cushings disease is called Pituitary Dependent
Hyperadrenocorticism. Pituitary Dependent Hyperadrenocorticism is usually caused by a small (even microscopic) pituitary tumor which produces ACTH despite blood cortisol levels. Rarely, large pituitary tumors are found. Using the home heating analogy, elevated room temperature (analogous to excess cortisol levels) arise because of a problem with the thermostat (analogous to pituitary gland). Excess cortisol levels then cause the clinical signs noted in Cushings disease. Both adrenal glands tend to enlarge in Pituitary Dependent Hyperadrenocorticism. Pituitary Dependent Hyperadrenocorticism is summarized below:
In about 10% of cases, an adrenal tumor produces excess cortisol independent of ACTH levels. These adrenal tumors are benign in about one-half of cases but malignant in the other half of cases. The pituitary senses high cortisol levels and decreases ACTH release. The remaining normal adrenal gland decreases its production of cortisol and overtime, may decrease in size. Again, the elevated blood levels of cortisol cause the clinical signs associated with Cushings disease. This type of Cushings disease is called Adrenal Tumor Hyperadrenocorticism and is summarized below:
Clinical Signs of Cushings Disease
The most commonly seen clinical signs in dogs affects with Cushings disease, or hyperadrenocorticism, are increased water consumption, increased urinations, increased appetite, distended abdomen, hair loss, and lethargy. Signs which are also noted are susceptibility to infections and slow wound healing.
Cushings disease usually compromises quality of life for affected dogs but is very rarely life-threatening. Fortunately trilostane treatment is generally very effective and safe method to control clinical signs and restore quality of life. Occasionally, Cushings disease may cause no clinical signs. Since treatment of Cushings disease has not been shown to extend lifespan, treatment of asymptomatic dogs is not recommended.
Diagnosis of Cushings Disease
Both laboratory testing and imaging studies are helpful in making the diagnosis of Cushings disease.
Lab tests are used to both determine both if Cushings disease is present and differentiate between Pituitary Dependent Hyperadrenocorticism and Adrenal Tumor Hyperadrenocorticism.
Tests which determine whether or not Cushings disease is present are called screening tests. Screening test used in dogs include ACTH stimulation, low dose dexamethasone suppression, and urine cortisol to creatinine ratio. Screening tests should not be performed when other illnesses are present because invalid false positive results are common. False positive results can also be seen when screening tests are performed on poorly controlled diabetic dogs. The steroid medications prednisone and prednisolone will erroneously be measured as cortisol to invalidate screen test results. Screening tests should not be preformed if prednisone or prednisolone has been given within the last 24 hours.
To perform ACTH stimulation, blood samples are taken before and one hour following injection of ACTH. Cortisol levels are measured in both blood samples. Dogs with Cushings disease (both Pituitary Dependent Hyperadrenocorticism and Adrenal Tumor Hyperadrenocorticism) show an exaggerated response. In about 90% of cases, ACTH stimulation identifies Cushings disease but 10% of affected dogs will have normal results. ACTH stimulation does not distinguish between Pituitary Dependent Hyperadrenocorticism and Adrenal Tumor Hyperadrenocorticism.
To perform low dose dexamethasone suppression, blood samples are taken before, 4 hours, and 8 hours following dexamethasone injection. Dexamethasone is a steroid medication which is not erroneously measured as cortisol. Dexamethasone is however, detected by the pituitary and acts to decrease ACTH release and suppress blood cortisol levels in normal dogs. Dogs with Cushings disease both types of Cushings disease fail to show suppressed cortisol levels at 8 hours. Most dogs with Pituitary Dependent Hyperadrenocorticism suppress at 4 hours but not at 8 hours while most dogs with Adrenal Tumor Hyperadrenocorticism fail to suppress at both 4 and 8 hours. This difference can be used to distinguish Pituitary Dependent Hyperadrenocorticism for Adrenal Tumor Hyperadrenocorticism.
To perform a urine cortisol to creatinine ratio, urine is collected at home and submitted for testing. Creatinine levels increase with more concentrated urine. By expressing the results as the ratio of cortisol to creatinine, differences in urine concentration are accounted for. Dogs with both types of Cushings disease can show elevated ratios.
Unfortunately, many normal dogs will have elevated urine cortisol creatinine ratios. All elevated results should be confirmed with either an ACTH stimulation or low dose dexamethasone suppression test. A normal cortisol creatinine ratio is helpful in assuring that Cushings disease is not present.
In most cases it is helpful to distinguish between Pituitary Dependent Hyperadrenocorticism and Adrenal Tumor Hyperadrenocorticism. As discussed previously, low dose dexamethasone suppression can be useful in making this distinction. Measuring ACTH blood levels is also very helpful in distinguishing between the two causes of Cushings disease. Dogs affected with Pituitary Dependent Hyperadrenocorticism will have elevated blood ACTH levels while those affected with Adrenal Tumor Hyperadrenocorticism will have normal to low blood levels.
Abdominal ultrasound is very helpful in distinguishing between Pituitary Dependent Hyperadrenocorticism and Adrenal Tumor Hyperadrenocorticism. In Pituitary Dependent Hyperadrenocorticism both adrenal glands are usually enlarged but normal in shape. With Adrenal Tumor Hyperadrenocorticism, one adrenal gland is usually enlarged (sometimes dramatically) and abnormal in shape while the other adrenal gland is smaller than normal.
Magnetic Resonance Imaging (MRI) and Computerized Tomography (CTI) can also be used to image adrenal glands.
Chronic Kidney Disease in Dogs and Cats
Etiologies of Chronic Kidney Disease in Dogs and Cats:
The most common cause of acquired kidney disease in pets is age-associated change to the kidneys resulting in progressive damage to the functional units of the kidneys. This leads to decreased ability to concentrate the urine followed by azotemia (elevation of kidney values). This is particularly common in cats but is also seen in dogs. Other causes of kidney disease are congenital abnormalities, toxic insults, proteinuria (excessive protein loss through the kidneys that is caused by the diseases glomerulonephritis or amyloidosis), infectious disease(s), and cancer.
Congenital kidney disease is often times recognized on initial lab work prior to neutering or at wellness checks. Toxic etiologies include exposure to things such as ethylene glycol (antifreeze), non-steroidal anti-inflammatory drugs (acetaminophen and ibuprofen are examples), grapes or raisins, certain plant types (including those in the Lily family), and specific classes of prescription and chemotherapy drugs. These toxins generally result in a syndrome referred to as acute renal failure, which is addressed differently than chronic renal failure, but exposure to smaller amounts of these drugs can lead to kidney injury and result in chronic disease later in life.
Glomerulonephritis is a disease characterized by excessive loss of protein through the functional units of the kidneys, the glomeruli. This is oftentimes associated with inflammation of the kidney and complete work-up is indicated for this disease. Amyloidosis is an extreme form of protein loss through the kidney caused by accumulation of the protein amyloid in the kidney’s glomeruli. This can be seen in certain breeds including the Shar pei dog and Abyssinian cat.
Infectious causes of kidney disease include pyelonephritis (bacterial infections of the kidney), Leptospirosis, and Lyme disease. Any infectious disease can also lead to glomerulonephritis by causing systemic inflammation and deposition of immune complexes in the glomeruli of the kidneys. Infectious diseases may result in acute or chronic renal failure.
Diagnostic Work-Up of Kidney Disease:
A thorough diagnostic work-up is indicated once kidney disease is initially identified. This is important in order to identify any treatable conditions that will allow the veterinarian and pet’s family to slow progression of the disease. This may also lead to specific treatment for identified causes of kidney injury and allow for reversal of some of that damage. Indicated tests include full lab work which consists of a chemistry panel, complete blood count and urinalysis, urine protein levels, urine culture and sensitivity, blood pressure determination, abdominal ultrasound, and, possibly, infectious disease titers.
Treatment of Kidney Disease:
Once a work-up has been completed, recommendations can be made to help slow the progression of kidney disease. The most important therapy is institution of a renal diet (kidney-appropriate diet). These diets are low quantity, high quality protein diets and are available by prescription only. Based upon the initial diagnostics, urinary tract infections can be addressed based upon culture and sensitivity, electrolyte abnormalities, elevations in phosphorous levels, and acid-base derangements are identified and treated, and prognosis can be determined. In late stages of chronic renal failure, anemia (low red blood cell count) can develop and certain drugs may be recommended to stimulate the bone marrow to produce more red blood cells.
Hypertension (high blood pressure) is a common sequela of kidney disease and is addressed by prescription drugs and careful monitoring of kidney values and blood pressure. Hypertension is oftentimes seen in conjunction with proteinuria and a drug in the ACE inhibitor class is initially used to treat both conditions. Kidney diets and adjunct therapies such as ultra low-dose aspirin and fatty acid supplementation also aid in the therapy of glomerulonephritis. Research has indicated that addressing proteinuria and blood pressure are as important as dietary therapy in management of long-term chronic renal failure patients.
Acute on chronic renal failure is a crisis situation when the kidney values rise and result in a patient feeling sick, becoming dehydrated, not eating or drinking, and possibly vomiting. Since the kidneys are unable to retain enough fluid and the patient is not able to intake adequate amounts of fluids for these losses, severe dehydration ensues, which furthers the crisis. This is managed by hospitalization for diuresis (aggressive intravenous fluid therapy), anti-nausea medication, and other therapy based upon diagnostics. Once discharged from the hospital, it is frequently recommended that these patients receive subcutaneous fluids (fluids administered under the skin) at home.
Prognosis for Kidney Disease in Pets:
Prognosis for kidney disease is variable and depends on what stage medical intervention is initiated. With any disease, early intervention is ideal, however, not always possible. It is recommended that pets have at least yearly lab work performed to identify kidney disease as well as other endocrine and metabolic conditions as early as possible. With careful monitoring and by addressing the treatable conditions, many patients can live happily for years with kidney disease.
Common Health Problems of Senior Dogs
Improvements in nutrition and veterinary care have led to our canine pets living longer lives. Although age is not a disease process per say, certain diseases are more common in older dogs. Diseases that are more commonly encountered are obesity, arthritis, dental disease, cancer, diabetes, kidney disease, and heart disease. These diseases will be briefly discussed in this review.
Obesity is defined as body weight exceeding ideal by at least 20% or development of health problems due to accumulation of excess body fat. The incidence of obesity in humans has significantly increased and is approaching 40% in the United States. Obesity is increasing in pet dogs and is most commonly seen in senior dogs. Obesity in Labrador retrievers has been demonstrated to result in a significantly shorter lifespan when compared to leaner counterparts. Obesity has been associated with orthopedic diseases, elevated triglycerides in blood, diabetes, urinary incontinence, and respiratory problems in dogs. Increased incidence of cancer may also be associated with obesity in dogs.
Older dogs are less active and have lower caloric requirements. Ideally, senior dogs should either be fed smaller amounts or changed to a lower calorie diet to prevent obesity from developing. Once obesity has occurred, changing to a lower calorie diet and gradually increasing activity together is most effective in promoting weight loss. Working with your veterinarian to provide specific dietary and exercise guidelines can be helpful in reversing obesity. Veterinarians may prescribe Slentrol, a medication that acts to decrease intestinal fat absorption and decrease appetite, to promote weight loss. The goal should be to achieve ideal body weight over a 4 to 6 month period. Monitoring body weight on a weekly or biweekly basis is vital to document progress.
Arthritis is commonly seen in older dogs. Arthritis may develop secondary to other orthopedic diseases such as an anterior cruciate ligament rupture. In many dogs however, there is no underlying joint disease or injury to cause the problem. While arthritis is not life threatening, it adversely affects quality of life.
Management of arthritis is best accomplished by using a staged multimodality approach. Weight loss if the animal is overweight can be very helpful. Veterinary physical therapists are helpful in promoting non-weight bearing exercises such as swimming and underwater treadmill training. Acupuncture can be very helpful in managing arthritis. Effectiveness of glucosamine in dogs as in humans is controversial. Some dogs may show improved comfort with glucosamine chondroitin sulfate therapy. There are a variety of non-steroidal anti-inflammatory drugs (NSAID’s) that have been developed for dogs that can be very helpful in alleviating arthritis-associated pain. While these medications are much safer than aspirin, they should only be given under the direction of a veterinarian. NSAID’s are contraindicated if concurrent kidney disease is present. Adverse side effects associated with NSAID’s in dogs include vomiting, GI ulceration, and liver disorders. Dogs who cannot receive NSAID’s can be managed with alternative pain relieving medications such as tramadol and gabapentin. Newer therapies such as intra-articular platelet rich plasma have shown promise in the treatment of arthritis. Finally, total hip replacement surgery can be utilized as a last resort for severe hip arthritis, which cannot be managed by other methods.
Dental disease is very common in senior pets. Signs of dental disease include odor to breath, inflamed or bleeding gums, visible dental tartar, and less commonly decreased appetite. Daily tooth brushing and regular dental cleanings are very helpful in preventing periodontal disease and tooth loss. Your veterinarian can also prescribe specific dental chew treats and prescription diets that are helpful in preventing dental disease. Veterinary dental specialist can offer root canals as an alternative to tooth extraction in some cases.
Cancer is more commonly encountered in senior pets. Since cancer can affect any of the dog’s organ systems, a wide variety of signs including poor appetite, weight loss, lethargy, difficulty urinating or defecating, skin masses or sores, vomiting, diarrhea, difficulty breathing or cough, seizures, and sneezing especially with one sided nasal bleeding. All skin and subcutaneous masses should be pointed out to your veterinarian so that they can be aspirated to determine the underlying cause and documented in the medical record. Regular six-month checkups are helpful in diagnosing cancer early in senior patients. As in people, cancer if diagnosed at an early stage is easier to treat. Treatment of cancer in pets has progressed significantly in the past 30 years. Specific treatment modalities for cancer in dogs include surgery, chemotherapy, radiation therapy, and immunotherapy.
Senior pets have been demonstrated to be at increased risk for developing diabetes. Obesity and a previous diagnosis of hyperadrenocorticism (Cushing’s Disease) have also been shown to be risk factors for developing diabetes mellitus. Diabetes is more common in female dogs. Diabetic dogs frequently present for increased thirst, increased urine volume, and weight loss. Some diabetic dogs may develop ketoacidosis that can results in poor appetite, vomiting, and lethargy. Diabetes is diagnosed by documenting elevated blood glucose and the presence of glucose and if ketoacidosis is present, ketones in urine. Diabetic ketoacidosis is a life threatening disease and affected dogs require hospitalization for IV fluids, intensive monitoring, and aggressive insulin therapy. Management of diabetes in dogs requires twice daily insulin injections and is best managed by feeding two equal lower carbohydrate meals each day. Intact female dogs are difficult to regulate and should be spayed. Even diabetic dogs that are well regulated are predisposed to developing cataracts. Cataract surgery can restore vision to these dogs.
Kidney disease is common in senior dogs. Signs of kidney disease include increased thirst, increased urine volume, decreased appetite, vomiting, odor to breath, and oral ulceration. Kidney disease is more successfully managed if discovered early. Performing lab work (CBC, serum chemistries, and urinalysis) ideally every 6 months but even annually is helpful in diagnosing kidney disease at an early stage. Laboratory signs of kidney disease include elevations of BUN, creatinine, and phosphorus in blood; dilute urine specific gravity, elevated protein in urine, and anemia. Urinalysis and urine culture are indicated in kidney disease to detect any underlying urinary tract infection. Abdominal ultrasound is helpful in assessing kidney architecture and screening the urinary system for stones and masses. Prescription kidney diets that are lower in protein, phosphorus, and sodium are helpful in managing kidney disease. When changing to a prescription kidney diet, the new diet is better accepted if the change is made gradually over a 7 to 10 day period. There are many different prescription kidney diets available for dogs and if your dog will not accept the first prescription diet, a different prescription diet should be tried. Some dogs who refuse prescription diets will accept homemade kidney diets. Your veterinarian can provide you with recipes. Dogs with more severe kidney disease may require initial hospitalization for IV fluid therapy. High blood pressure can be seen with kidney disease and should be treated to prevent a more rapid progression of kidney disease. Dogs with excess protein in their urine can benefit from treatment with benazepril or another ACE inhibitor to help slow the progression of kidney disease. If diagnosed early, many dogs with kidney disease can be successfully managed for years.
Small breed senior dogs are at increased risk for developing mitral regurgitation. In mitral regurgitation, nodular degeneration of the mitral valve leads to leaking of blood from the left ventricle through the mitral valve and into the left atrium. Over time enlargement of the left atrium and ventricle occur. In more severe cases, left sided congestive heart failure can occur and fluid can develop in the lungs. Signs of congestive heart failure include cough, shortness or breath, and decreased stamina. Chest radiographs and echocardiogram are used to diagnose mitral regurgitation and differentiate this condition from chronic airway disease and collapsing trachea, which can also be seen in toy and miniature poodles. Diuretics, vasodilators, and ionotropic drugs are used to manage heart disease in dogs. Many dogs with mitral regurgitation can live for years with a good quality of life.
Commonly Asked Questions About Parvo Virus
Parvovirus infection in dogs is a serious and often life threatening infection of dogs. Parvovirus has been recognized as a cause of viral diarrhea for thirty years. The virus has undergone changes over the years, with new strains arising that are more virulent then the parent strain. Although vaccination is effective in preventing infection in many dogs, parvovirus remains a common cause of illness in pet dogs.
How did my dog get parvovirus?
Dogs acquire the infection by one of two ways. The most common is exposure to the virus in the feces of infected dogs. Some puppies can acquire the virus in utero or shortly after birth. Parvovirus is shed in the feces of infected dogs 3-4 days after exposure, and is shed for a total of 7-10 days. Shedding of the virus in stool often occurs before the onset of clinical signs. Parvovirus can infect dogs of any age or breed, but young dogs between 6 weeks and 6 months of age are at highest risk. Certain breeds of dogs may be more susceptible to infection. These include Rottweilers, Doberman pinschers, Labrador retrievers
What is parvovirus?
Canine parvovirus is a member of the parvovirus family. Many different types of species-specific parvoviruses exist. They are very small and hardy viruses; they can live in the environment for prolonged periods of time and remain infectious. The parvovirus of one animal species does not infect another species. Another example of a parvovirus is feline panleukopenia (“feline distemper”) virus.
What are the signs of parvovirus infection?
The classic sign of parvovirus infection is bloody diarrhea. Vomiting, anorexia, lethargy and depression are also common signs. Many times dogs will exhibit one of these other signs before developing diarrhea. This can provide a challenge to diagnosing dogs with parvovirus, since many other diseases cause these same non-specific signs.
My dog was vaccinated for parvovirus. Why did they get the disease?
Although the current available parvovirus vaccines are very effective, they are not perfect. Puppies receive some antibodies against parvovirus from their mother. These antibodies can block a pup’s own antibodies, and can inhibit a strong response to vaccination. Maternal antibodies can last as long as 18 weeks, sometimes even longer. If a puppy has not yet fully responded to vaccination by producing its own antibodies, it is susceptible to infection. This can occur even if the owner has been diligent in vaccinating their puppy on schedule. Occasionally, a mature dog’s immune system does not respond well to the vaccine. Rarely, this dog can develop clinical infection.
How can I prevent the disease?
Adherence to puppy vaccination protocols is essential in providing protection against infection. Keeping young dogs away from dogs with unknown vaccination histories may also help. Many owners avoid taking their puppies to public places until they have received their entire series of vaccinations. Dogs which are infected with parvovirus and develop clinical signs are often immune for life once they recover from the infection.
I have other dogs in my home. Are they at risk of infection?
Once parvovirus infection has been diagnosed, all other dogs the patient has contacted have been exposed to the virus. Well vaccinated, healthy older dogs usually have enough antibody protection to be immune from disease. Young dogs, particularly other puppies, are at risk. Since parvovirus is very stable in the environment, owners can carry the virus on clothes, shoes and other inanimate objects. For this reason, we limit visitation of our parvovirus patients, and keep them isolated from other hospitalized pets. It is important that the environment be disinfected. A 1:30 dilution of chlorine bleach will call the virus in a few minutes. Promptly cleaning up fecal material decreases potential pathogen contact.
Diabetes in Dogs and Cats
Diabetes mellitus a common disease in both pets and people. This article will review the common signs associated with diabetes in cats and dogs, as well as the treatment options available.
The most common sign of diabetes in cats and dogs is an increase in water consumption. This is associated with an increase in urine output. Many owners may seek veterinary care because their dog is having “accidents” in the house, or their cat box needs to be changed frequently. Some pets will start eating more, or losing weight with a good appetite. Occasionally the signs are subtle, and owners may just sense their pet “isn’t right”. A unique feature of diabetes in dogs is that it leads to cataract formation. Many of our canine diabetic patients present for blindness, or because their caretaker noted they were developing cataracts. In the most extreme cases, pets can develop life-threatening ketosis, or an increase in the blood’s acidity. These pets can collapse and become unresponsive. Ketosis can progress to death if the pet is not seen immediately. Fortunately, ketosis is rare, and most of our clients detect changes in their pet well before it develops.
Many people are familiar with the human forms of diabetes, often called “juvenile onset” or “Type 1″ and “adult-onset” or “Type 2″. Juvenile onset diabetes has a low heritability, and is the result of a lack of insulin. This type of diabetes requires daily insulin injections. Adult onset diabetes is often linked to obesity, and is inherited in many families. This type of diabetes is the result of a decrease in the body’s ability to respond to insulin. Type 2 diabetes is treated with dietary change, weight loss, exercise, oral medication and occasionally, injectable insulin. Our pets seem to suffer from similar forms of diabetes, although Type 1 is much more common than Type 2.
Many of the same principles used to treat human diabetics are used to treat our pets with diabetes. We often change the diet, monitor exercise and encourage weight loss in overweight pets. Unfortunately, the oral hypoglycemic agents used so widely in people have been less successful in cats and dogs. Almost all of our animal diabetics receive insulin injections. There are many different insulin preparations available, and different types work better in some pets than others. Your veterinarian may try several types to determine which one works best in your dog or cat. Although intimidating at first, most pet owners quickly become experts at administering insulin injections!
Once a pet is diagnosed with diabetes, they require close monitoring by their veterinarian. A recent study showed that on average, a pet will have one to two illnesses per year that are related to their diabetes. However, with diligent care, many diabetic pets live active and healthy lives for many years.
Diarrhea is one of the most common reasons that pets are seen by their veterinarians. Although most causes of diarrhea are related to disease of the gastrointestinal tract, occasionally it is a manifestation of disease processes arising in organs such as the liver and pancreas.
The first step in the diagnostic work-up of diarrhea is to determine if the diarrhea is acute or sudden in onset, or is of longer duration (chronic). Chronic diarrhea is defined as loose stool that persists for greater than 1 month, or is intermittently seen for several months. The second step in determining the cause of the diarrhea is to decide if the stool has characteristics suggesting origin in the small intestine or large intestine. These first two steps then determine the remaining work up.
Small bowel diarrhea is characterized by large volumes of watery to semi-liquid stool with little or no discomfort or straining associated with the bowel movement. Occasionally the pet may have some urgency associated with the defecation. Weight loss may be present if the diarrhea has been persistent.
Large bowel diarrhea is characterized by straining and urgency to defecate. There is often fresh blood or mucous in the stool. Weight loss is rare with purely large bowel diarrhea unless food intake is decreased. Some pets have diseases of both the large and small intestine, resulting in combinations of symptoms.
A minimum data base-consisting of a complete blood count, biochemical profile, urinalysis, and fecal examination-are obtained in almost every case of diarrhea. Occasionally, other tests, such as x-rays and ultrasounds, are performed. Fiber-optic endoscopy of the gastrointestinal tract often is used in chronic cases, or in instances of foreign body ingestion. A surgical exploration is performed when there is an obstruction of the bowel, or if the problem is beyond non-surgical correction.
Hypoadrenocorticism (Addison’s Disease)
Hypoadrenocorticism is a disease characterized by low adrenal gland output. Most commonly, this is associated with destruction of the adrenal gland, although occasionally it is related to pituitary gland abnormalities. The diagram below illustrates the normal mechanisms present for adrenal gland stimulation. The pituitary hormone ACTH is released from the brain and stimulates the adrenal glands to produce cortisol and other hormones. The increased cortisol level from the adrenal gland is detected by the pituitary gland, which then decreases ACTH output until the cortisol level again falls below normal.
Hypoadrenocorticism occurs either because the adrenal glands have been damaged and can no longer produce cortisol, or because the pituitary gland is no longer producing ACTH. The disease is most common in young female dogs, but can be seen in male dogs and occasionally is diagnosed in older pets. This disease is very rare in cats.
Signs of hypoadrenocorticism can be subtle and similar to many other diseases. Lethargy, chronic vomiting, diarrhea, and intermittent weakness are commonly seen. In its most serious form, the affected animal can collapse. If Addison’s disease is suspected, the diagnosis is easily confirmed using the ACTH stimulation test. A blood sample is taken before and after administration of synthetic ACTH, and cortisol levels are measured. If the adrenal gland is atrophied, it cannot respond to the ACTH and the cortisol level will not change. Some steroids can interfere with cortisone measurement and individuals must be kept off steroids prior to testing.
Treatment consists of replacing the deficient adrenal hormones. This can include daily medications or long-lasting injections. Either treatment is highly effective, although treatment can be costly in large dogs.
Periodic rechecks are required to “fine-tune” medication, but long-term prognosis is excellent.
Immune-mediated Diseases in Dogs and Cats
Dogs and cats develop autoimmune diseases similarly to people. These diseases occur when the patient’s own immune system attacks its own cells or tissues due to a loss of tolerance for self. The majority of these cases are idiopathic (no known etiology can be found), although ruling out underlying disease processes is warranted to optimize therapy for each patient. Underlying diseases associated with immune disease in dogs and cats include cancer, systemic lupus erythematosus (SLE, Lupus), infectious diseases including tick-borne Rickettsial infections, and reactions to drugs and vaccinations. Immune-mediated diseases can vary in severity and each patient responds differently to the medications necessary to control the disease. The immune-mediated diseases we commonly see are immune-mediated thrombocytopenia (ITP), immune-mediated hemolytic anemia (IMHA), immune-mediated polyarthritis (IMP), immune-mediated neutropenia (IMN), and immune-mediated destruction of red blood cell precursors/pure red blood cell aplasia.
Diagnostic work-up is unique to each disease process, however, there are certain common diagnostic tests recommended for all of the immune-mediated diseases. Chest X-rays and abdominal ultrasound allow us to rule out cancerous etiologies. An anti-nuclear antibody test (ANA) is run to search for Lupus, and serum titers are run for Rickettsial infections. Additional work-up may include a Coomb’s test looking for antibodies on red blood cells in cases of IMHA, a reticulocyte count to evaluate for the bone marrow’s response to anemia, bone marrow aspirate examination, and joint taps to search for inflammatory changes consistent with polyarthritis. If an underlying cause is found for the immune-mediated disease, primary treatment of that underlying disease is recommended to aid in the therapy of the patient. Regardless of the underlying disease, however, immunosuppressive therapy will be necessary to stop the immune system from attacking itself.
Drugs used for these diseases vary, however, the majority are placed on high dosages of steroids, azathioprine (Imuran), and cyclosporine. Side effects of the drugs are common, however, the drugs are tapered as the immune system responds and the patient improves. Our goal is to use the lowest dosages of drugs possible to control the disease while causing the least amount of side effects possible. Steroids will cause excessive thirst and urination, excessive hunger, and possibly panting, hair loss, muscle weakness, and liver enlargement. Azathioprine is generally well-tolerated, however, idiosyncratic reactions can occur causing low blood cell counts, liver toxicity, and pancreatitis. Cyclosporine can cause gastrointestinal side effects manifesting as inappetence, vomiting, and diarrhea. All of these drugs can lead to the development of secondary infections as they are suppressing the immune system. Again, these drugs are tapered to the lowest dosage possible to control the underlying disease and to minimize the side effects on the patient.
Prognosis varies with type of disease. The most severe cases are ITP and IMHA with a 75% chance for survival for ITP and a 50% chance for survival with IMHA. In the literature, patients with immune-mediated destruction of red blood cell precursors have a better prognosis than IMHA patients with greater than 75% survival, however, it can take prolonged therapy to induce remission and these patients may require multiple blood transfusions during this time. The majority of IMP and IMN cases do quite well with therapy, although occasionally cases can be refractory to therapy.
Regardless of the cause, these immune-mediated diseases can be expensive and frustrating to treat. The medications used will cause side effects in the short-term, but these will resolve as the drugs are tapered to the lowest dosage possible to control your pet’s disease.
Pancreatitis in Cats
Cats can develop acute pancreatitis characterized by severe inflammation and systemic consequences similar to dogs (please see “Acute Pancreatitis in Dogs” handout). Acute pancreatitis in cats may be secondary to infectious diseases such as Toxoplasmosis or may be idiopathic (no known etiology can be found). However, the majority of cats that develop pancreatic inflammation have chronic pancreatitis. Chronic pancreatitis in cats is caused by immune-mediated inflammation within the pancreas. The cause of this inflammation is largely unknown and can be accompanied by inflammation of the gastrointestinal tract (inflammatory bowel disease) and inflammation within the liver (cholangiohepatitis). 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. These include intermittent although occasionally severe vomiting, inappetence, weight loss, fever, abdominal pain, and diarrhea. Labwork findings are non-specific and may include elevated white blood cell counts and elevated liver enzymes. Amylase and lipase, the routine pancreatic enzymes found on most laboratory panels, have been shown to be non-diagnostic in cats.
As in dogs, the diagnosis of chronic pancreatitis can be elusive and 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 ultrasound. We believe that this number is a bit low as our equipment and expertise has improved over the years. The most sensitive and specific diagnostic test is a blood test called the feline pancreatic lipase immunoreactivity (FPLI), which picks up approximately 90% of the cases. This test confirms the diagnosis as well as serves as a baseline to help assess response to therapy.
The goal of therapy for feline chronic pancreatitis 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 institution of steroid therapy.
Prognosis 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 life, although we can usually taper the drug down to low-dose daily or every-other-day therapy. Prognosis can be worse with concurrent inflammatory bowel disease or cholangiohepatitis and these diseases may require further work-up with endoscopy or liver biopsy.
Vomiting in Pets
Vomiting is one of the most common reasons pets are taken to their veterinarian. Vomiting is defined as an active expulsion of stomach and intestinal contents, and is differentiated from regurgitation, which is a passive process characterized by lack of abdominal push. Although most of us think that vomiting is a sign of stomach problems, vomiting can be associated with disease in almost any body system, including the central nervous system, kidneys, pancreas, and liver. A detailed history provided by the pet owner regarding duration of vomiting and character of the vomitus, coupled with age and species, are the cornerstones of diagnosis.
In general, we classify vomiting in the broad categories of acute (sudden onset) and chronic (long term). This helps us narrow down the possible causes and guides further diagnostic tests. Many times, the cause of vomiting is obvious (e.g., the puppy who has swallowed a toy or an old cat with kidney disease). Occasionally, your veterinarian must play the role of detective to find the more obscure or hidden reasons for the vomiting. A minimum data base-consisting of white and red blood cell count, complete biochemical profile and urinalysis-are crucial pieces of information gathered on almost every vomiting animal to aid in the diagnosis process. Additional testing often includes x-rays of the abdomen, ultrasound of the abdomen, and additional blood tests.
If these tests do not yield a definitive diagnosis, more extensive work-up is required. Endoscopy, laparoscopy, and surgical exploration may be necessary to establish a diagnosis, and consultation with experts in a variety of specialties assists in guiding further diagnostic tests and establishing treatment protocols.