Cushing’s Disease(hyperadrenocorticism) is a major metabolic disorder and is relatively common in dogs. Certain breeds of dogs are more prone to Cushing’s Disease than others especially
Beagles, Boston Terriers, Boxers, Dachshunds, Poodles, and Yorkshire Terriers.
This is generally a disease of older pets. Gender doesn’t seem to matter much.
Cushing’s Disease( hyperadrenocorticism) affects the adrenal glands. The Adrenal Glands produce the different types of steroidal hormones that help regulate metabolism and keep electrolytes in balance. They affect every organ in the body. One of the most important and powerful of the hormones that the adrenal glands produce is called cortisol or cortisone. Cortisone is critical to life, strength, and vitality …to little and mammals die or become very sick; a disease we call Addison’s disease or hypoadrenocorticism.
Cushing’s Disease is the opposite of Addison’s Disease. Withe Cushing’s Disease, the Adrenal Glands produce too much cortisone. Cushing’s Disease affects many parts of the body. It affects the muscles by causing them to shrink. While taking steroids can increase muscle mass, as so many athletes are supposed to be doing, taking too much of them will cause loss of muscle. Because one of the roles of cortisol is to regulate blood glucose levels by taking amino acids from muscle cells for conversion to sugar in the liver. An important function but if the Adrenal Glands are producing too much cortisol, then too many amino acids are used and this makes the muscles smaller and weaker.
Cushing’s Disease also affects the skin ,making the skin thin and fragile and causes a large amount of hair loss
Cushing’s Disease and the Blood
Excess cortisol caused by the walls of the blood vessels to become too thin which can lead to easy bruising, hematomas, and so forth.
Cortisol plays an important role in maintaining blood pressure, but too much can lead to excessive blood pressure.
Cushing’s Disease and Bone
Cortisone affects the calcium balance in bones, and too much causes the bones to lose calcium making the bones smaller and weaker. This process also leads to excess calcium loss through the kidneys.
Cushing’s Disease and the Brain
Cortisone affects your pet’s mood, behavior, and sleep patterns. This is where you as a pet owner can help. If you notice drastic changes in your pets behavior, be sure to mention it to the Vet
Cushing’s Disease and the Kidneys
One of the normal functions of Cortisone is to stimulate the kidneys to function properly; but too much will put the kidneys into overdrive so to speak. This can lead to kidney failure, One of the big clues that a patient might have Cushing’s Disease is that the patient is drinking and urinating a lot more than normal and that the urine is not very concentrated. It is very watery looking.
Cushing’s Disease and The Immune System
.Steroids work very well at reducing severe itching, asthma, allergies, inflammation, and most other immune related diseases. It prevents the immune system cells from releasing all the chemicals that are needed to fight off allergens, germs, and repair damaged tissue. This is great if you’re treating an over-active immune system…
But, with Cushing’s Disease producing too much cortisol, there is too much immune suppression and your animal will lose the ability to fight off infections making the patient susceptible to the millions of organisms that invade the body on a daily basis
Cushing’s Disease and Liver
Because cortisone stimulates the liver to work harder than normal at making glycogen, over time the liver becomes larger. Your vet might notice an enlarged liver on palpation or on radiographs.
The Different Possible Causes Of Cushing’s Disease:
Too much ACTH : This is known as Pituitary Dependent Cushings Disease.
This isn’t too complicated, but ACTH is a hormone released by the pituitary gland in the brain and ACTH is released into the blood stream whenever the brain senses a need for more cortisol.
The pituitary gland is prone to getting a benign, slow growing cancer called an adenoma. Not too big a deal as far as cancers go, but it makes the pituitary release more than normal amounts of ACTH and that makes the adrenal glands get bigger and stimulated to produce more than normal amounts of cortisone.
Pituitary Dependent Cushings Disease is the most common type by far, but there are several other possible causes They’re all lumped into a category called Non-Pituitary Dependent Cushings Disease.
Other Possible Causes of Cushings:
The other major cause of Cushing’s Disease is from tumors of the adrenal Cortex. About half the time the tumor is benign, the main problem being that it leads to excess cortisone production. The other half of the time the tumor is malignant and in addition to causing the adrenal gland to produce way too much cortisone, it will often invade and cause severe disease of the nearby liver, major veins, and lymph nodes.
.There is one other possible cause of Cushing’s and it’s pretty rare. It’s called Ectopic ACTH Syndrome. Basically it means that some cancer somewhere other than the pituitary or adrenal gland happens to start producing ACTH.
Tests for Cushing’s
Blood tests that are performed regularly often pick up Cushing’s Disease before there are any other signs, It is a good practice to have regular blood work done especially on older dogs..
Often there are elevations of glucose, protein, and infection in the urine of dogs with Cushing’s, but not all the time.. What does show up is a low specific gravity: The urine is almost water like with this disease. Once we get a urine sample, getting a specific gravity reading is a standard and easy procedure.
A skin biopsy is usually done to help figure out why a pet’s skin is unhealthy and the biopsy results indicate the possibility of Cushing’s.
X Rays can be used to detect
Calcified Adrenal Glands.
Calcification of other tissues
Enlarged livers which can be associated with Cushing’s
Poor bone density which can be associated with Cushing’s
Treatment of the Disease:
Treatment of the Pituitary Tumor if Present. The most common treatment is Anipryl (L-Deprenyl). This is the same medication used to treat senility (cognitive dysfunction) in dogs and Parkinson’s disease in humans. Very few side effects, but should not be used along with anti-depressant drugs or Prozac. It takes 1-2 months to see improvement.
A drug called Lysodren (Mitotane) selectively kills the parts of the adrenal gland that produces cortisol. This helps, but it complicates other things; your vet will carefully go over all adjustments that will be needed.
If Mitotane is use, the dose will need to be monitored with ACTH stimulation tests. You may also have to supplement your pet with cortisone medications such as prednisone.
Ketaconazole is another medication sometimes used to treat Cushing’s. It reduces cortisol production fairly successfully, but many pets don’t tolerate the side effects well and it’s a little bit expensive.
Surgical Removal of the Adrenal Glands
Surgical removal is possible but not commonly done. It’s very difficult to manage electrolyte levels, blood pressure, and all the other roles associated with the adrenal glands synthetically. Sometimes just one adrenal gland will be removed…the one with the tumor…but the problem is that the other gland is often atrophied and not working.
Cushing’s Disease (hyperadrenocorticism) is extremely serious life threatening disease and can require medication for the rest of the dog’s Life. Owners of Beagles, Boston Terriers, Boxers, Dachshunds, Poodles, and Yorkshire Terriers Should be especially on the watch for symptoms. Remember you are y our pets advocate If you suspect anything let the vet know and request he check for Cushing’s.