Cushing’s Disease (Hyperadrenocorticism) in Dogs

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Cushing’s disease (hyperadrenocorticism) in dogs is a condition that results from the chronic overproduction of excessive glucocorticoid in the body. In the normal dog, the pituitary gland produces a hormonal agent called ACTH, which promotes the adrenal gland to produce the glucocorticoid hormonal agents necessary for the function of lots of systems in the body. If something fails in the pituitary gland or adrenal gland and excessive glucocorticoid is produced, then Cushing’s disease establishes. This is an extremely complicated disease with a wide range of symptoms and causes. This article will try to provide a succinct description of the disease, its symptoms, how it is diagnosed, and its treatment.


Who gets Cushing’s disease?

Cushing’s disease is considered a disease of middle age and older dogs and felines. It is much more common in dogs. This disease is comparable in felines other than that in felines up to 80% likewise have concurrent diabetes mellitus. This article will describe the issue as it happens in dogs. The typical age of contracting the disease is around 6 or 7 years with a variety of two to sixteen years. There is equivalent distribution in between males and women and there does not appear to be an increase of the disease in any one type.

What are the symptoms of Cushing’s disease in dogs?

As an outcome of the chronically raised glucocorticoids (steroids), the affected dogs develop a timeless mix of significant scientific signs and sores. The disease advances gradually. A research study revealed that most dogs had at least one symptom of the disease from one to 6 years before the disease was identified. Since the symptoms happen so slowly, the owner typically associates the changes to “old age.” Some dogs will have just one symptom, while others might have numerous.

Increased Water Consumption and Urination:

The most common symptom is increased consumption of water and the resultant increased urination (polyuria/polydipsia). The dogs drink in between two and ten times the normal quantity of water and the resultant increase in urination follows. This symptom exists in over 85% of all animals with Cushing’s disease. Previously housebroken animals might begin to have mishaps since their bladders fill rapidly with the overproduction of urine.

Boost in Appetite:

Increase in appetite (polyphagia) is another typical medical symptom that shows up in around 80% of the affected animals. Dogs might start taking food, getting into the trash, pleading continuously, and become really protective of their food. Regardless of having other symptoms, the owner might feel that the dog is alright because of his good appetite.

Abdominal Enlargement:

Abdominal enhancement is a typical symptom in up to 80% of the affected dogs. The potbellied look is a result of the moving of fat to the abdominal area and a weakening and wasting of muscle mass in the abdominal area.

Loss of hair and Thin Skin:

Hair loss and thinning of the skin are likewise common symptoms in dogs with Cushing’s disease. It is estimated that between 50% and 90% of the afflicted animals establish these symptoms. Hair loss (alopecia) is among the most common factors that owners bring their dog in for examination. The hair loss typically begins over the areas of wear such as the elbows and progresses to the flanks and abdomen till eventually just the head and extremities have hair. The skin may also end up being thin and be quickly harmed and sluggish to recover.

Increased panting, persistent urinary tract infections, or losses in reproductive ability are other symptoms frequently noted with this disease.

Cushing’s Disease has two forms

There are two different unique forms of the disease. There is pituitary dependent hyperadrenocorticism (PDH) and there is an adrenal-based disease.

Pituitary dependent hyperadrenocorticism:

PDH includes the oversecretion of ACTH by the pituitary gland. ACTH is a hormonal agent that promotes the adrenal gland to produce glucocorticoids. The pituitary gland is most likely overproducing ACTH since of a pituitary tumor. The PDH type of the disease is accountable for around 80% of the cases of canine Cushing’s disease.

Adrenal-based hyperadrenocorticism:

The adrenal-based type of the disease is normally a result of an adrenal tumor that causes an oversecretion of glucocorticoids. Adrenal growths are accountable for around 20% of the cases of Cushing’s disease. There is also a kind of the disease called “iatrogenic” Cushing’s disease that happens as an outcome of providing the animal high doses of steroids. In this kind of the disease, symptoms of Cushing’s disease will go away when the steroids are ceased.

Diagnosis

Cushing’s disease can provide with a range of symptoms and might likewise be involved with several various disease procedures. For that reason, it is advised that any dog thought of having Cushing’s disease ought to have a complete blood count (CBC), blood chemistry panel, and urinalysis performed as a regular part of the evaluation. Typical problems in these tests consist of boosts in alkaline phosphatase, and ALT (liver enzymes), increased cholesterol, reduced BUN (a kidney function test), and water down urine (low specific gravity).

There are numerous different tests that can be carried out to get a definitive diagnosis of Cushing’s disease. Sometimes the vet might perform more than one test to assist validate the medical diagnosis or to figure out which type of the disease is present. A medical diagnosis of Cushing’s disease, nevertheless, must never ever be made on the basis of lab tests alone. The dog needs to be revealing symptoms of the disease, and have a case history constant with the diagnosis.

The 3 most common “screening” tests are the urine cortisol: creatinine ratio, the low dose dexamethasone suppression test, and ultrasound.

Urine Cortisol:

Creatinine Ratio: In this test, the owner typically collects a urine sample at home (where the animal is not stressed out). The sample is sent by the vet to a special lab for testing. Many dogs with Cushing’s disease have an unusual result. Nevertheless, there are other illness that can also cause abnormal outcomes. So if this test is unusual, additional diagnostic testing should be performed.

Low Dose Dexamethasone Suppression Test:

The low dose dexamethasone suppression test works in identifying Cushing’s disease in dogs. When offered low dosages of dexamethasone, normal dogs show a marked decline in blood cortisol levels when tested 8 hours later. The majority of dogs (more than 90%) with Cushing’s disease do not have a decline in cortisol level after being provided dexamethasone. The results can often assist determine which kind of disease is present.

ACTH Stimulation Test:

This is another test that is typically used in the diagnosis of Cushing’s disease today. It will not compare the two types of hyperadrenocorticism, but it may aid in the diagnosis in tough cases. It is likewise used to evaluate the efficiency of therapy.

Abdominal Ultrasound:

Abdominal ultrasound is useful in three aspects. First, it is an excellent test to evaluate all the abdominal organs in the dog. Second of all, it is used to study the size and shape of the adrenal glands. The adrenal glands in pituitary dependent hyperadrenocorticism are usually normal in size or bigger. If a tumor exists however, one adrenal gland is frequently abnormally large or of unequal shape. Finally, if a tumor is suspected, ultrasound can assist determine any metastasis to other organs.

High Dose Dexamethasone Suppression Test:

This blood test, which is not used typically, might help to is used to distinguish between pituitary dependent hyperadrenocorticism and adrenal-based hyperadrenocorticism.

Treatment

Treatment includes several various options. Depending upon the type of disease, surgery can be performed. If an adrenal tumor is identified, then surgical elimination might be a viable choice. There are numerous different kinds of tumors that can get into the adrenal gland and their treatment will be based on the particular growth type.

Non surgical treatment is the most frequently used treatment for most cases of canine Cushing’s disease. About 80% of the cases of Cushing’s disease in the dog are of the pituitary type, and because both the adrenal and the pituitary type will react efficiently to some of the oral treatments, numerous veterinarians do not carry out the diagnostics essential to compare the two various kinds. There are presently several different oral medications being used to treat canine Cushing’s disease.

Lysodren:

Until recently, Lysodren (likewise referred to as mitotane, and o, p’- DDD) was the only treatment available for pituitary dependent Cushing’s disease. It is practical to use and is reasonably low-cost and is still most likely the most utilized treatment. The drawback of this drug is that it can have some serious side effects and routine blood-monitoring needs to be performed. During the initial stages of the therapy, the dog should be very carefully kept an eye on, and there need to be close communication between the vet and the owner.

The use of Lysodren is rather like chemotherapy. It works by ruining cells of the adrenal gland that produce the corticosteroid hormones. As the number of corticosteroid-producing cells is minimized, although the pituitary gland continues to produce excess ACTH, the adrenal gland is less able to react, so the quantity of glucocorticoid being produced is decreased. The issues develop when too much of the adrenal cortex is exterminated. The animals may then have to be placed on prednisone, either short or long term. The Lysodren is at first offered daily while the animal is being kept track of for a decrease in the symptoms (water usage, appetite). On the 8th or 9th day of the initial therapy, the dog has to be taken a look at and an ACTH stimulation test is carried out to figure out if the drug is working. If the goal is accomplished, upkeep therapy is started. If the goal has actually not been reached, then the dog generally stays on the daily medication for 3 to 7 extra days and is reconsidered up until the correct results are attained. If the dog ends up being lethargic, throws up, or has diarrhea, or if the treatment does not work by 30 days, then the treatment strategy is reassessed. If treatment succeeds, then symptoms must resolve within 4 to 6 months. A specific percentage of dogs will relapse and have to go through the day-to-day therapy once again at some point in their lives. If a dog ever becomes ill while on Lysodren, the Lysodren ought to be stopped immediately and the dog should be analyzed by a vet. If the therapy succeeds, the dog will need to be on Lysodren for the rest of his life.

Trilostane:

Trilostane is a newer treatment that is used to treat some dogs with Cushing’s disease. It is more expensive, however might be an alternative treatment for dogs with adrenal tumors. Just like Lysodren, the dog is reconsidered consistently during the preliminary phase of treatment, and ACTH stimulation tests are carried out. Oftentimes, after numerous months of therapy the dose needs to be increased.

Ketoconazole:

Ketoconazole is an oral antifungal agent that has been used extensively given that the mid 80s. Among the side effects of ketoconazole is that it disrupts the synthesis of steroid hormonal agents. It therefore acquired some appeal as a treatment for Cushing’s disease. However, it is hardly ever used today.

L-deprenyl (Anipryl):

L-deprenyl (Anipryl) has been advocated for the treatment of Cushing’s disease in dogs, but its effectiveness has entered concern.

Summary

Cushing’s disease is a disease that impacts middle age to older dogs. The impacted animal has a characteristic presentation including increased water intake and resulting increased urination, increased hunger, loss of hair, and a potbellied appearance. There are numerous diagnostic tests readily available, in addition to numerous treatments.

Also read: Addison’s Disease (Hypoadrenocorticism) in Dogs

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