Agatha is an 11-year-old F/S DSH first seen 3 months ago. The owners complained that she had beeen moping around for the past week and was more "clingy" than normal. She had vomited twice and urinated outside of the box on a few ocassions. My physical examination at that time was completely normal. Her heart rate was 168 bpm, there were no palpable thyroid nodules, and her weight was 11.3 pounds.

I saw the cat again last week, with the new complaint of sounding hoarse for 3 weeks. The cat was also eating and drinking less, and she was lethargy and less active. My physical examination revealed that her body weight was down to 10.2 pounds (i.e., a 1 pound weight loss). The cat also had mild anisocoria, and now I could palpate bilateral thyroid nodules!

I performed routine blood work (CBC, serum chemistry panel) which was completely normal. Her serum T4 value was also normal at 1.5 µg/dl (reference range, 0.8 - 4.0 µg/dl), and the free T4 by dialysis was normal at 23 nmol/L (reference range, 10-50 nmol/L).

It's amazing how much this cat has deteriorated in just 3 months. How can you explain the cat's thyroid goiter with the normal T4 and free T4 results? Do my results rule out thyroid disease?

My Response:

Both the serum thyroid tests and history rule out hyperthyroidism, but this cat could still have thyroid hyperplasia or neoplasia. The cervical masses you palpate certainly may be thyroid nodules but could also be lymph nodes, parathyroid tumors, or another type of subcutaneous tumor.

I'd start with fine needle aspiration of the cervical masses. Those results will dictate where our workup should go next. If those results are consistent with thyroid tissue, the next step would be to do thyroid scan (scintigraphy) in order to document that the cervical tumors are indeed thyroid in origin and to rule out thyroid carcinoma.

Źródło: endocrinevet.blogspot.com

How do we best diagnose hyperadrenocorticism in dogs? Which is the best diagnostic test? A presumptive diagnosis of should be made from clinical signs, physical examination, routine laboratory tests, and diagnostic imaging findings, but the diagnosis must be confirmed by use of cortisol hormone assays and pituitary-adrenal function tests. For screening tests designed to diagnose Cushing's syndrome, we have three choices:

* ACTH stimulation test

* Low-dose dexamethasone suppression test (LDDST)

* Urinary cortisol:creatinine ratio (UCCR)

Which screening test is best?

Unfortunately, none of the diagnostic tests used in dogs with suspected Cushing's syndrome are totally reliable, and both false-positive and false-negative results are common. Because there are inherent problems with these diagnostic tests, the veterinarian is frequently challenged when attempting to properly interpret the dog’s tests results. It is important to remember, however, that the predictive value of a positive screening test result for Cushing's increases in direct proportion to the number and severity of clinical signs and biochemical changes that develop in this disease. Therefore, one must always remember the importance of the dog’s signalment, history, and physical examination findings when interpreting the diagnostic test results of all pituitary-adrenal function tests.

Who should be tested for hyperadrenocorticism?

Testing for hyperadrenocorticism in a dog should be done because they have one or more clinical signs of the disease. Typically the disease is insidious and slowly-progressive, so most dogs have had clinical signs, such as abdominal enlargement, panting, muscle weakness, thin skin, lethargy, polyphagia, polyuria and polydipsia (PU/PD) for months to even years before the owners recognize a problem and seek veterinary help.

Who should NOT be tested for hyperadrenocorticism?

Testing for Cushing's syndrome is not recommended if the only abnormality is an increased serum alkaline phosphatase (SAP) activity on a serum chemistry panel, and the dog is otherwise apparently healthy. It is difficult enough to interpret endocrine tests in dogs with clinical signs of the disease; if they have no clinical signs, all of the endocrine tests may be difficult to interpret because of false-positive and false-negative results. The first step in workup in these dogs may include an abdominal ultrasound or bile acid testing. One should not screen dogs for hyperadrenocorticism when the dog is sick with clinical signs that would not be related to Cushing's syndrome (e.g., vomiting, anorexia, weight loss). Many non-specific illnesses and other systemic diseases will produce false-positive results with the endocrine tests. Remember, hyperadrenocorticism is only slowly progressive, so hyperadrenocorticism is never an emergency diagnosis. Before diagnostic testing is performed, it is therefore always good to ask oneself: if the test results would indicate hyperadrenocorticism, would I then feel confident to start treating with mitotane (Lysodren®) or trilostane (Vetoryl®) given the clinical picture of the patient? Would treatment help the dog's clinically signs? If either answer is "no," then it is probably best not to screen for hyperadrenocorticism in the first place.

My dog has clinical signs of hyperadrenocorticism and now other nonrelated illness - now can I test?

If the dog has any or all of the clinical signs of hyperadrenocorticism, yes, you should proceed with testing of the pituitary-adrenal axis. However, it is necessary first to ensure that the dog is not being exposed to exogenous glucocorticoids, including topical glucocorticoids on the eyes, ears or skin. First check with the owner to ensure that they are not applying topical glucocorticoids to their own skin - sometimes, dogs may ingest glucocorticoids by licking steroid-containing cream off of the owner's skin. If there is any doubt, ask the owner to bring in all and any medications that dog is receiving (including over the counter preparations) and anything that the owner or owner's family might be using in order to verify that no glucocorticoids are in any of these medications. Next, obtain a routine database (CBC, serum chemistry analysis, and complete urinalysis) before any endocrine testing is undertaken. Finding the expected clinical pathology changes in a dog with suspected Cushing's syndrome helps confirm what the initial history and physical exam suggested. Typical abnormalities in dogs with hyperadrenocorticism include high values for serum alkaline phosphatase, alanine aminotransferase, low to low-normal serum urea nitrogen, and dilute urine specific gravity. On the CBC, we may see a 'stress' leukogram (elevated mature neutrophils and monocytes, decreased lymphocytes and eosinophils), and a hematocrit and RBC count at the high end of normal.

What about now? Now should I use one of the screening tests?

If all the analyses point to hyperadrenocorticism at this stage, test away! In the next blog, I'll be discussing the pros and cons of the ACTH stimulation test for Cushing's syndrome.

Źródło: endocrinevet.blogspot.com

Despite its name, diabetes insipidus is not related to the more commonly known diabetes mellitus, and it does not involve insulin or sugar metabolism. The name comes from Greek, where it is roughly translated to mean the “excessive discharge of bland urine.” This is in contrast to diabetes mellitus, which can be translates as the “excessive discharge of sweet urine.”

Diabetes insipidus is caused by problems with antidiuretic hormone (ADH or vasopressin), a pituitary gland hormone responsible for maintaining the correct level of fluid in the body. Either the pituitary gland does not secrete enough of this hormone (called central diabetes insipidus), or the kidneys do not respond normally to the hormone (called nephrogenic diabetes insipidus).

Affected dogs urinate in large volumes and drink equally large amounts of water. The urine is very dilute even if the animal is deprived of water (normally, urine becomes more concentrated when an animal is dehydrated.).

Increased urination may be controlled using desmopressin acetate, a drug that acts in a way similar to antidiuretic hormone. Water should not be restricted. Treatment is usually life-long.

Źródło: animalendocrine.blogspot.com

The holidays have gone by, but many of us still have candies lying around the house. Xylitol is an artificial sweetener found in many chewing gums and other candies, and it is extremely toxic to dogs. We add xylitol to candy because it tastes like sugar, but our body does not digest it – it contains no calories. While it is safe for us, it is very dangerous for dogs.

How does xylitol hurt my dog?

Unlike us, when a dog ingests xylitol (such as by getting into a pack of gum), the dog’s body falsely recognizes it as a tremendous amount of sugar. This causes the dog’s pancreas to release a lot of insulin, as if the dog’s blood sugar were very high. Because it is not actually high, this increase in insulin causes a dangerous drop in blood sugar (hypoglycemia). While some dogs merely develop temporarily elevated liver enzymes, suffer from acute liver failure, hemorrhage, blood coagulation, and death.

How much xylitol is dangerous?

It takes only one or two pieces of gum to cause toxicity in a 10kg dog (about 22 lbs). If your dog eats chewing gum or a candy containing xylitol, you should immediately call Animal Poison Control at (888) 426-4435 or contact your veterinarian / an emergency clinic.

Is xylitol dangerous to cats?

We know little about how xylitol affects cats, but it may not be toxic. If your cat ingests xylitol, you should watch your cat carefully, but you do not need to call animal poison control.

Źródło: animalendocrine.blogspot.com

Diabetes mellitus (often called simply diabetes) is a disorder in which the level of sugar in the blood is too high. In dogs, it is usually caused by a deficiency of the hormone insulin. During digestion, carbohydrates are broken down into glucose (a simple sugar), which is absorbed into the bloodstream. Once in the bloodstream, glucose must enter the body?s cells in order to be used for energy. Insulin signals the body?s cells to absorb glucose from the blood.

A lack of insulin creates two dangerous conditions. First, the body?s cells cannot absorb glucose without insulin; they begin to starve despite the abundant glucose. Second, because the body?s cells do not absorb glucose, the blood glucose level remains dangerously high.

With its cells starving for energy, the body begins to break down its protein, stored starches, and fat. As muscle is broken down and carbohydrate stores are used up, weakness and weight loss occur. As fat is broken down, substances called ketones are released into the bloodstream where they can eventually cause diabetic ketoacidosis, a severe complication of unregulated diabetes.

Meanwhile, the excess glucose circulating in the bloodstream can have harmful effects as well, including development of cataracts, pancreatitis, and skin and urinary tract infections. The excess glucose is eventually excreted from the body through the kidneys. As the glucose passes through the kidneys into the urine, it pulls water with it by diffusion. This causes increased urination, which leads to increased thirst.

Diabetes often develops gradually, and owners may not notice the signs during the initial stage of the disease. Common signs include increased thirst and urination, increased appetite, and weight loss. Diabetic animals often develop chronic or recurrent infections. Dogs with poorly controlled diabetes often develop cataracts, which commonly leads to blindness.

A diagnosis of diabetes mellitus is based on finding high levels of sugar in the blood and urine.

To successfully manage diabetes, you must understand the disease and take daily care of your pet. Treatment involves a combination of weight loss (if obese), diet, and insulin injections generally twice daily. Usually after being diagnosed with diabetes, dogs are hospitalized for a day or two, and multiple blood samples are taken to measure the blood sugar level throughout the day. This information is used to determine the amount and timing of your pet?s meals and the dosage and timing of insulin injections. After this initial stabilization, your veterinarian will provide appropriate instructions on managing this regimen at home. Periodic reevaluation is necessary to ensure that the disease is being controlled. Based on these reevaluations, you may have to change your pet?s treatment regimen over time.

Źródło: animalendocrine.blogspot.com

We are an overweight society and our pets are no different. By far, the most common explanation for an overweight pet is simple: lack of exercise and too much to eat. But what if you feed your dog sensibly, exercise adequately, and your dog still has a weight problem?

There could be a number of reasons your dog is still overweight, including heredity, temperament, and overall activity level. However, a disease may be causing your dog to become overweight or obese. Hormonal diseases such as hypothyroidism and Cushing?s syndrome commonly cause weight gain. Hormone pills or tablets with cortisone-like drugs could also be contributing to the obesity.

Hypothyroidism is deficient thyroid hormone, and it causes alterations in cellular metabolism that affect the entire body. The dog may not feel like exercising and may gain weight because calories consumed are not matching calories expended. The weight gain then makes the dog feel like exercising even less. Hypothyroidism is usually inherited and a common genetic illness in dogs. Untreated hypothyroidism means a lower quality of life for your dog, but with the proper thyroid supplementation, this condition can be easily controlled, allowing your dog to enjoy a good quality of life.

Cushing's syndrome (hyperadrenocorticism) is chronic excess of a glucocorticoid hormone, cortisol. This hormone is essential for functions such as maintaining blood glucose levels, metabolizing fats, keeping major organs functioning properly. There are different types of Cushing?s with many symptoms and causes, so it can sometimes be difficult to diagnose. Furthermore, its onset is slow, so its symptoms are often mistaken for signs of age. Cushing?s syndrome can cause reduced activity, change in appetite, and hair loss. Other symptoms include an increased thirst and urination, muscle weakness, and obesity. The cause of the Cushing?s syndrome determines the treatment, which is also influenced by the overall health of the dog.

Adequate exercise and proper diet are essential for all animals, but if your dog is overweight and you suspect an underlying disease, see a veterinarian for a thorough physical exam including laboratory tests.

Źródło: animalendocrine.blogspot.com

We are very proud of the warmth and quality of care that our hyperthyroid cat patients receive while they board with us after their radioiodine treatment. This fun video will give you a better idea of what it actually feels like to be a cat boarding in our state-of-the-art facility. The Hypurrcat Spa at The Animal Endocrine clinic is a warm, welcoming and comfortable facility, staffed by the world's leading veterinary endocrinologist, Dr. Mark E. Peterson.

For more information, please visit our website or call us at (212) 362-2650.

Źródło: animalendocrine.blogspot.com

As you can see in the above video, before treatment she was getting ready to go into a hyperthyroid crisis (sometimes called a thyroid storm). She was experiencing severe heart issues, including tachycardia (rapid heart rate) and ventricular arrhythmia (irregular heartbeat), due to her hyperthyroidism. She was anxious, agitated, panting, and underweight.

The second video shows the same cat, after she has been cured of her hyperthyroidism with a radioiodine treatment at the Hypurrcat Spa. This video is taken 3 months after her I-131 treatment. She is now relaxed and she has gained weight back. Recent blood tests reveal that her T4 level has returned to normal, meaning that she is now cured of hyperthyroidism.

For more information about feline hyperthyroidism, please visit the Animal Endocrine Clinic website, the Hypurrcat website and Facebook page, or follow us on Twitter. You may also call us for more information: (212) 362-2650.

Źródło: animalendocrine.blogspot.com

Dr. Mark E. Peterson is a world-renowned specialist in endocrinology (hormonal disorders) of the dog and cat. He specializes in endocrine problems such as diabetes, hyperthyroidism, hypothyroidism, Cushing's and Addison's disease.

Dr. Peterson served as head of endocrinology and nuclear medicine at The Animal Medical Center in New York for over 30 years. He now sees patients at his own private practice, the Animal Endocrine Clinic, with two locations in New York City and Westchester County. The AEC is the world's foremost animal clinic for feline and canine endocrinology and is the only veterinary hospital devoted entirely to animals with endocrine problems. Each location has a Hypurrcat facility dedicated solely to treating hyperthyroid cats with radioiodine. Dr. Peterson created his clinics in an environment that combines scientific knowledge with his compassionate care to effect a cure.

Dr. Mark Peterson is also very active in writing and teaching other veterinarians. He has published hundreds of journal articles, book chapters, and research abstracts and is the editor of a leading textbook on veterinary endocrinology. With more than 250 teaching presentations to his credit, Dr. Peterson is a frequent speaker at veterinary and medical seminars both in the United States and around the world.

Źródło: www.drmarkepeterson.com

Hypurrcat is a treatment center built exclusively for radioiodine treatment of cats with hyperthyroidism.     
             
      Feline hyperthyroidism was first documented 31 years ago by Dr. Mark E. Peterson and coworkers. Since then, hyperactive thyroid disease has become the most common hormonal disorder of domestic cats. Due to continued research, hyperthyroid cats now have the same therapeutic choices as human patients including medication to suppress the thyroid hormone production, surgical removal of the thyroid tumor, or radioactive iodine (radioiodine I-131) therapy to destroy the thyroid tumor responsible for the condition.    
             
      Of these treatment options, radioiodine therapy is considered by authorities to be the treatment of choice for this condition in cats. Overall, radioiodine provides a simple, effective, and safe cure, regardless of the cat’s age. If left untreated, however, hyperthyroidism can be fatal.    
             
      At Hypurrcat we can now easily and completely cure this disease with our radioiodine procedure, destroy your cat's thyroid tumor, and return your cat to a normal thyroid state.

Źródło: www.hypurrcat.com