Pet Endocrine Diseases ~ Hormonal

If you see your pet have symptoms that aren’t really coming up in search engines, you may need an expert opinion on the matter. At Atlas Animal Hospital, we can diagnose and treat pet Endocrine diseases of all types and ensure that all is well with animals that might be dealing with hormonal issues. We can help diagnose and cure the issue. Finding out what’s bothering your pet is our #1 concern, that is why we are the number one choice of Vets in Vancouver.

The major endocrine glands in the dog by Merck Manuals

The major endocrine glands in the dog by Merck Manuals

Endocrine hyper- and hypofunction: Endocrine diseases stem from imbalances in hormone levels. Hormone imbalances can affect your pet’s health in many ways. Although some endocrine disorders are not life threatening, many are fatal if not diagnosed and treated. Diseases can develop because an endocrine gland itself is faulty or because the control of that gland is faulty (i.e., a problem in the pituitary can harm the adrenal glands). Endocrine diseases develop when the body produces too much hormone (hyper- diseases) or too little hormone (hypo-diseases). A tumor or other abnormal tissue in an endocrine gland often causes it to produce too much hormone. Hormone excess disorders often begin with the prefix “hyper.” For example, in hyperthyroidism, the thyroid gland produces too much thyroid hormone. When an endocrine gland is destroyed, removed, or just stops working, not enough hormone is produced. Hormone deficiency disorders often begin with the prefix “hypo.” For example, in hypothyroidism, the thyroid gland does not produce enough thyroid hormone.

The major endocrine glands in the cat by Merck Manuals

The major endocrine glands in the cat by Merck Manuals

Treating endocrine system disease: Endocrine diseases caused by too much of a hormone can be treated surgically (tumor removal), with radiotherapy (such as the use of radioactive iodine to destroy an overactive thyroid gland), or with medications used to block the tumor from over-secreting the hormone. One can normally treat hormone deficiency syndromes simply by supplementing the missing hormone. For example, one can treat diabetes mellitus by giving insulin injections. Steroid and thyroid hormone replacements can usually be given orally. Dogs and cats taking hormone replacement therapy must be monitored for side effects and periodically retested to make sure the drug dosage is correct. In some cases, such as after an endocrine tumor is surgically removed, the remaining gland will recover and hormone replacement will no longer be needed. Unfortunately, most of these treatments are life-long.

Endocrine Disorders

Acromegaly: Acromegaly (also known as hypersomatotropism) is a hormonal condition resulting from over-secretion of growth hormone, known as Somatotropin from the pituitary gland. This hormone is responsible for growth from birth to adulthood. At adulthood, secretions of the growth hormone slow dramatically and growth normally stops. In acromegaly, the bones continue to grow. Because the bone plates will still close upon entering adulthood, continuing growth is not in normal proportions. The effect of excess growth hormone is similar to the effect of steroids in the respect that it causes insulin resistance. Animals with acromegaly often are diabetic. Since acromegaly is an endocrine disease, its sufferers can also be prone to neuropathy.
In cats: Cats and people usually have a pituitary tumor which is the cause of acromegaly. Over 90% of feline sufferers are male; there’s no sexual predisposition in humans. The clinical features of feline acromegaly include large head and paws, forward-jutting lower jaw, weight gain, and enlarged abdomen and organs, such as the heart, liver, and kidneys. Acromegaly was thought to be a rare condition, but a recent UK study of diabetic cats with poor to adequate glycemic control showed that nearly a third of them showed signs of acromegaly. Testing confirmed acromegaly in over 90% of those. So as many as 1 in 3 hard-to-control diabetic cats may have acromegaly!
In dogs, the condition often develops due to excess progestrone secretion (as happens with ovarian cysts). The usual canine sufferers of acromegaly are unspayed females. Spaying usually may cure the condition, depending on whether the pancreas is still able to secrete sufficient insulin. (Any type of diabetes may if unregulated eventually shut down the pancreas; see amyloidosis.) Using medication containing progesterones can also result in an excess of growth hormone.

Diabetes mellitus is commonly divided into two types, depending on the origin of the condition: Type 1 diabetes, sometimes called “juvenile diabetes”, is caused by destruction of the beta cells of the pancreas due to an autoimmune disorder and Type 2 diabetes is caused by either insulin resistance or insufficient insulin production, which can be triggered by any number of causes. Type 2, if not well-treated, deteriorates[2] as it destroys beta cells of the pancreas, eventually leading to complete insulin dependence. If well-treated early, some proportion of cats experience remission.
Fast Facts: The typical canine diabetes patient is middle-aged, female and overweight at diagnosis. The typical feline diabetes patient is middle-aged, male, and overweight at diagnosis. Cats are one of the few species capable of developing a form of diabetes which is very much like that of Type 2 in humans. Both can develop amyloid deposits which inhibit the endocrine pancreas from working properly. Type 2 diabetes is rare in dogs, but between 80-95% of cats with diabetes suffer from the Type 2 form. The number of dogs diagnosed with diabetes mellitus has increased three-fold in thirty years. Looking back on survival rates from almost the same time period, only 50% survived the first 60 days after diagnosis and went on to be successfully treated at home. With treatment, diabetic dogs are able to survive as long as non-diabetic dogs of the same age and gender. The number of cats diagnosed with diabetes mellitus has increased at least twofold in the last 15 years, and now ranges from 1 in 400 to about 1 in 50 cats. With early appropriate diet change and treatment, it is now possible for 20 to 90 percent of Type-2 cats to expect diabetic remission.

Juvenile-onset Panhypopituitarism (Pituitary Dwarfism): In juvenile-onset panhypopituitarism, also called pituitary dwarfism, the front portion of the pituitary gland does not fully develop or is disrupted by a tumor. This affects several other hormone-producing glands, leading to a variety of signs. In particular, the lack of growth hormone causes the young animal to be dwarfed.

Hypothyroidism: This is the medical term for an underactive thyroid gland. One of the many things the thyroid gland is responsible for is to regulate metabolism. When not enough thyroid hormone is secreted, the metabolism slows; secreting too much results in hyperthyroidism and a too-rapid metabolism. The thyroid gland is actually controlled by another gland, the pituitary gland. It signals the thyroid to produce its hormone and is responsible for the amount of thyroid hormone in the blood. Symptoms of hypothyroid are dry skin and coat, often a loss of hair at the rear portion of the body, sluggishness and weight gain even if the animal has his/her meals reduced, skin that is cold to the touch. The animal may also deliberately seek out warm places to lie. These symptoms are shared with many other medical conditions; as a result, hypothyroidism isn’t always a first thought when diagnosing.

Hyperthyroidism: This is the medical term for an overactive thyroid gland. One of the many things the thyroid gland is responsible for is to regulate metabolism. When too much thyroid hormone is secreted, the metabolism quickens; secreting too little results in hypothyroidism and a slowed metabolism. Hyperthyroidism is an endocrine disease, like diabetes; those with endocrine-related disorders are more prone to various types of neuropathy. As with diabetes mellitus, hyperthyroidism can mean polydipsia and polyuria symptoms. It is not a common problem in dogs, but it’s important to remember overmedicating for hypothyroidism can show up as hyperthyroid test results.

Hypercalcemia: refers to an abnormally high blood concentration of calcium in the blood. Cats are more prone to this condition than dogs. Calcium is the most abundant mineral found in the body, approximately 99% is found in bone and the remaining 1% in extra cellular fluid (fluid found outside of the cells and between the cells in body tissues). It is essential for several functions including providing strength to bones and teeth, cardiac function, proper nerve impulses and muscle contractions, blood clotting. It is stored in the skeleton and released as it is required. In combination with phosphorous, it forms calcium phosphate, the dense, hard material of bones and teeth. Hypercalcemia is an abnormally high level of calcium in the blood (greater than 12 mg/dl). Causes of hypercalcemia include; cancer, acute or chronic renal failure, primary hyperparathyroidism (a condition where the parathyroid gland produces too much parathyroid hormone), ingestion of certain houseplants ( hypervitaminosis D (excess levels of Vitamin D), generally caused by over supplementation or rodenticide poisoning. Some cases are idiopathic, meaning there is no known cause. Less common causes include Addison’s disease, hyperthyroidism, granulomatous disease, certain cancers and vitamin A toxicosis. What are the symptoms of hypercalcemia in cats? Anorexia, Constipation or diarrhea, Dehydration, Increased thirst and urination, Lethargy, Vomiting, Weight Loss, Hypocalcemia

Hypocalcemia is an abnormally low level of calcium in the blood. The most common causes of hypocalcemia in dogs include previous surgical removal of the parathyroid glands (leading to hypoparathyroidism), kidney disease or failure, and calcium imbalance in nursing females. Hypoparathyroidism is characterized by low blood calcium, high phosphate, and low parathyroid hormone concentrations. It is uncommon in dogs, but can be caused by previous removal of the parathyroid glands as a treatment for hyperthyroidism or for a parathyroid tumor. Hypocalcemia causes the major signs of hypoparathyroidism by increasing the sensitivity, or excitability, of the nervous system. Common signs include muscle tremors and twitches, muscle contraction, and generalized convulsions. Diagnosis of hypoparathyroidism is based on history, clinical signs, low blood calcium, high phosphorous, and low serum parathyroid hormone levels. We must also rule out other causes of hypocalcemia.

Pancreatic insulin-secreting tumor (insulinoma): Insulinomas are slow growing, well-encapsulated, functional tumours of the beta cells of the pancreatic islets. They secrete inappropriately high amounts of insulin, irrespective of the serum glucose concentration. They are often malignant, with a high metastatic rate to regional lymph nodes, liver and omentum. 60% of insulinomas are carcinomas, which are more likely to be endocrinologically active whereas the others are adenomas. Blood glucose concentration is normally maintained within a narrow homeostatic range because several tissues are able to use only glucose as an energetic substrate. These tissues are particularly affected by the hypoglycaemia which occurs with hyperinsulinaemia and they include neurones, blood cells, renal medullary cells and fibroblasts in healing wounds. The release of hormones antagonistic to insulin (such as glucagon, growth hormone, glucocorticoids and catecholamines) also contributes to the pathogenesis and clinical signs observed in animals with insulinoma.

Cushing’s syndrome (hyperadrenocorticism): Cushing’s syndrome describes the signs and symptoms associated with prolonged exposure to inappropriately high levels of the hormone cortisol. This can be caused by taking glucocorticoid drugs, or diseases that result in excess cortisol, adrenocorticotropic hormone (ACTH), or CRH levels. Cushing’s disease refers to a pituitary-dependent cause of Cushing’s syndrome: a tumor (adenoma) in the pituitary gland produces large amounts of ACTH, causing the adrenal glands to produce elevated levels of cortisol. It is the most common non-iatrogenic cause of Cushing’s syndrome, responsible for 70% of cases excluding glucocorticoid related cases. An easy way to distinguish Cushing’s syndrome from Cushing’s disease is that the measured ACTH levels are lower in the former. The decrease in ACTH is due to increased negative feedback of cortisol on the hypothalamus and anterior pituitary. This pathology was described by Harvey Cushing in 1932. The syndrome is also called Itsenko-Cushing syndrome, hyperadrenocorticism or hypercorticism. Cushing’s syndrome is not confined to humans and is also a relatively common condition in domestic dogs and horses. It also occurs in cats, however, rarely.

Addison’s disease (hypoadrenocorticism): Addison’s disease, whether in dogs or humans, is an endocrine system disorder that occurs when the adrenal glands fail to produce enough hormones for normal function. The adrenal glands – located above the kidneys – secrete glucocorticoids such as cortisol and mineralocorticoids such as aldosterone; when proper amounts of these are not produced, the metabolic and electrolyte balance is upset. Mineralocorticoids control the amount of potassium, salt and water in the body. The disease is also known as hypoadrenocorticism, adrenal insufficiency, or hypocortisolism, and is fatal if left untreated. All causes for Addison’s disease are not yet known. The usual causes are genetic, often related to autoimmune disorders, where the body attacks and kill its own tissue (“immune mediated destruction”). Other cases are caused by various disease processes, including atypical Addison’s -the failure of the pituitary gland to secrete ACTH, the hormone which stimulates the adrenal prodution of cortisol.