Cushing syndrome in dogs - Symptoms and causes


In December 2008, the Food and Drug Administration (FDA) approved the first drug in more than 10 years to treat Cushing's disease in dogs.

Hyperadrenocorticism, commonly known as Cushing's disease, is a condition that arises when the body produces a hormone called cortisol in abundance. Cortisol is produced and stored by the adrenal or adrenal glands, two small glands located in the upper part of the kidneys.

Dogs, cats and horses, like humans, can suffer from Cushing's disease, although it is more common in dogs than in cats or horses.

"Cortisol is one of the body's natural steroids," explains veterinarian Ann Stohlman, VMD, of the FDA's Center for Veterinary Medicine, to add that a normal amount of cortisol is good: "It helps the body adapt at times of stress". Cortisol also helps regulate proper body weight, tissue structure, skin conditions and other indicators of good health.

But too much cortisol weakens the immune system, leaving the body vulnerable to other diseases and infections.

Two common types

Most cases of canine Cushing's disease occur naturally and are of the type, either hypophysic-dependent, or adrenal-dependent. About 80 to 85 percent of Cushing cases are hypophyseal-dependent, which means that the disease is unleashed by a pituitary or pituitary tumor, a pea-sized gland located at the base of the brain.

The pituitary gland makes several hormones, including adrenocorticotropic (ACTH). The pituitary tumor causes an overproduction of ACTH, which travels through the bloodstream to the adrenal glands, stimulating them to produce more cortisol than the body needs.

In the other 15 to 20 percent of dogs with Cushing, a tumor in one of the adrenal glands, or both, produces excess cortisol.

The type of Cushing can determine the kind of treatment to be prescribed. Veterinarians use blood tests to diagnose the disease and differentiate between that originating in the pituitary gland and that caused by the adrenal glands. They can also use an ultrasound to help detect a tumor in one of the adrenal glands.

In general, Cushing's disease affects middle-aged and older dogs. The disease progresses slowly and the first symptoms are not always detected. These include:

  • an increase in thirst
  • an increase in urination
  • an increase in appetite
  • a reduction in activity
  • excessive panting
  • thin or delicate skin
  • loss of hair
  • recurring skin infections
  • abdomen growth, resulting in a "bloated" appearance
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Most veterinarians treat both suprarenal-dependent and pituitary-dependent Cushing disease with medication. The only way to "cure it" is to remove the adrenal tumor, when it is adrenal-dependent and has not spread, Stohlman says. However, given the complexity and risks of surgery, most cases are treated with medication. Surgical techniques to remove pituitary tumors in dogs are under study, but surgery is not a widely available option.

Although Cushing's disease is usually a lifelong condition, it can usually be managed with medication. "It is important that the dog is seen regularly by a veterinarian and subjected to blood tests," Stohlman warns. "Monitoring the blood helps determine the correct dose, which may need to be adjusted from time to time."

In general, frequent blood tests are necessary during the first months after starting treatment, and every few months after that, depending on how the dog responds to the treatment and its tolerance to the medication.

Vetoryl (trilostane) capsules, the most recent approval medication for treating canine Cushing disease, is also the first to be approved to treat both hypophysis-dependent and adrenal-dependent Cushing in dogs. This prescription medication works by slowing the production of cortisol in the adrenal glands. In studies on the drug, the most common side effects were vomiting, lack of energy, diarrhea and weight loss. Vetoryl should not be given to a dog that:

  • suffer from kidney failure or liver disease
  • take certain medications for the treatment of heart conditions
  • be pregnant

The safety and efficacy of Vetoryl was demonstrated in several studies. Success was measured by improvements in both blood test results and symptoms (normal appetite levels and activity, and a decrease in gasping, thirst and urination).

Only another drug, Anipryl (selegiline), is approved by the FDA to treat Cushing's disease in dogs, but only that of the pituitary-dependent and uncomplicated type.

Veterinarians have often "alternately" used a drug used for chemotherapy in humans, Lysodren (mitotane), to treat Cushing's disease in dogs. Lysodren destroys the layers of the adrenal gland that produce cortisol. This requires careful monitoring and can have serious side effects.

“Alternative” or “out of the indicated” means that veterinarians may prescribe medications for humans to animals, legally, for uses other than those indicated on the label, or for other species or in doses other than those specified therein . But, as dogs can react unpredictably to medications for humans, Stohlman warns, it is good to have available treatments that have been studied in dogs, and specifically approved for them.

"The treatment of Cushing's disease is a balancing game," says Stohlman. "But dogs suffering from the disease can lead a good life if they are closely watched by a veterinarian, and if the owner is solicitous in taking the dog to his blood tests and administering the medication as directed."

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Cushing's disease or Hyperadrenocorticism

Cushing's disease, known as hyperadrenocorticism, is a common disease in older dogs, so it is usually confused with the age process. It is usually more common in dogs than in cats. When it manifests, the dog gains weight, loses hair, urinates in the house ... Its owner thinks that the dog is very old and suffers the consequences of it. His behavior could even make him consider premature euthanasia, however, if it is Cushing's disease, it is a treatable disease. The treatment can extend your pet's life by enjoying it more and allowing you to enjoy a much better life. For all this, and to determine if your dog manifests these symptoms, it is essential that the owner of a pet knows the basic facts about Cushing's disease.

Those responsible for your dog having hyperadreconocorticism are two small glands located on the kidneys, known as adrenal glands. When these glands produce an overproduction of hormones, Cushing's disease manifests. All symptoms are those of an excess of cortisone in the body. Cortisone relaxes the ligaments of the abdomen and causes enlargement of the liver, decreases the growth of the hair and the thickness of the skin. Increases appetite and thirst, which causes weight gain and a greater desire to drink and urinate. Cortisone decreases muscle mass, causing muscle weakness and weakness. Cortisone also regulates the mineral content of the blood.

The adrenal glands are regulated by the pituitary gland or pituitary gland located at the base of the brain. The pituitary produces a hormone known as ACTH, which stimulates the adrenal glands to produce cortisone.

In 85% of cases, the pituitary gland secretes more ACTH than necessary because there is a tumor in the pituitary. Occasionally, the tumor is located in the pituitary gland. Another possible cause for Cushing's disease to manifest in the dog is to receive too much corticosteroid, either in well-injected pills. However, sometimes it is the price that must be paid to control another more serious illness.

Symptoms of the dog with Cushing's disease

The first thing that owners of a dog with Cushing's disease detect is their need to drink at all hours and urinate more. Females usually urinate at home, unable to endure.

Owners are often forced to refill their drinking fountain often because they drink a lot, while they also have to take them out more times, because they need to urinate frequently. However, do not forget that these are just some of the symptoms and are not all that can manifest. They are also characteristic symptoms of Addison's disease, precisely the opposite of Cushing's disease.

These dogs have a higher risk of getting urinary infections.

Another visible symptom of cortisone excess is the dog's appetite increase. It seems they never finish being satiated and are always asking for more food. They also gain weight and become obese.

The coloring of your hair may vary to a more brown or dark shade.

The dog may appear lethargic, not wanting to move. More still than usual.

Cortisone enlarges the liver, so that in an advanced state of the disease, the dog seems fat or have thick legs. At this point, the dog can barely exercise and its activity decreases significantly.

Going up and down stairs will become increasingly difficult and, over time, he will refuse to move too much.

Your skin will be more susceptible to infections and cuts.

Apparently, the races that have a higher risk of suffering from this disease are the Bulls Terriers, Boston Terriers, Yorkshire Terriers, Silky Terriers, Dachshunds and poodles. Females seem a little more susceptible than males to diseases of the adrenal glands. As for age, it usually manifests in dogs older than five years.

Cushing's disease is diagnosed by a series of blood tests. There are three types, so it is also treated in three different ways. The tests not only diagnose the disease but can tell us if the problem is in the pituitary gland or in the adrenal gland (s).

In addition, an ultrasound test of the adrenal glands can be performed to rule out or detect a tumor.

Routine analysis usually shows that the pet has an unusually high level of alkaline phosphatase, cholesterol, glucose, as well as diluted urine.

If these results are shown along with other dog symptoms, Cushing's disease may be suspected and additional tests may be carried out. In this case, the dexamethasone suppression test or the ACTH stimulation test could be done. Both usually confirm or rule out the presence of the disease and determine its cause.

Since the ACTH stimulation test is expensive and requires hospitalization of the dog, another test can be done whose recent studies have shown that it can be effective: analyzing cortisol / creatinine in the urine can be effective to rule out dogs that do not have Cushing's disease However, when the test is positive and confirms the disease, it is necessary to do the ACTH stimulation test, since other diseases can also give a false positive in this test.

It is not unusual for a dog with Addison's disease to have another endocrine disease such as diabetes or recurrent pancreatitis.

If the tests determine that you have a tumor in the adrenal gland, it will have to be removed. It is a very specialized and dangerous operation, so many veterinarians prefer to be done by a specialist or decide to medicate the animal.

Tumors in the pituitary gland are not usually removed. Most cases with Cushing's disease are usually treated with medication.

Iatrogenic Cushing's disease is caused by frequent use of cortisol. The excessive amount of cortisol tells the adrenal glands that they have to stop producing cortisol in the body, which causes them to decrease in size. His treatment is the slow withdrawal of cortisol. A sudden or too rapid interruption of cortisol could have serious consequences such as diarrhea, vomiting, vascular collapse or even death.

Pituitary-dependent hyperadrenocorticism: caused by microtumors in the adrenal gland, which in turn causes the adrenal glands to produce too much cortisol. In this case, both adrenal glands may appear enlarged.

There is no cure for pituitary-dependent hyperadrenocorticism. Currently it is the symptoms that are treated.

If Cushing's disease is not treated, the consequences will deteriorate the dog's health causing congestive heart failure, liver, kidney failure, diabetes and neurological disorders. In addition, dogs with Cushing's disease are more susceptible to infections.

The most dangerous period is the first six months after starting treatment. None restores the normal function of the adrenal glands, but once the six month period has elapsed, even with the disease, the dog can continue to live for more years with a good quality of life.

What is cushing syndrome?

Cushing syndrome is also known as hyperadrenocorticism and it is a endocrine disease (hormonal) that occurs when the body produces high levels of the hormone cortisol chronically Cortisol is produced in the adrenal glands, located near the kidneys.

An adequate level of cortisol helps our body respond normally to stress, helps balance body weight, have a good structure of tissues and skin, etc. In contrast, when the body undergoes an increase in cortisol and there is an overproduction of this hormone, the immune system weakens and the body becomes exposed to possible infections and diseases, such as diabetes mellitus. This hormone in excess can also damage a lot of different organs, significantly reducing the vitality and quality of life of the animal that suffers from this syndrome.

Further, the symptoms are easily confused with those caused by normal aging. So many dogs are not diagnosed with cushing syndrome since the symptoms go unnoticed by some owners of old dogs. It is vital to detect the symptoms as soon as possible, perform all possible tests until diagnosing the origin of the cushing syndrome and treat it as soon as possible.

Causes of hyperadrenocorticism in dogs

There is more than one origin or cause of cushing syndrome. Specifically there are three Possible causes that may be causing cortisol overproduction:

  • Malfunction of the pituitary or pituitary gland
  • Malfunction of the adrenal or adrenal glands
  • Iatrogenic origin that occurs secondary to a treatment with glucocorticoids, corticosteroids and medications with progesterone and derivatives to treat certain diseases in dogs

As we have already mentioned, the adrenal glands produce the hormone cortisol, so a problem in these can trigger cushing syndrome. But the adrenal glands, in turn, are controlled by the hormone that is secreted in the pituitary gland or pituitary gland, which is located in the brain. Therefore, a pituitary problem can also cause a lack of control of cortisol levels. Finally, glucocorticoids and other medications are used to treat certain diseases in dogs, but if they are misused, for example in contraindicated states or in very high amounts or times, they can end up producing cushing syndrome since they alter cortisol production.

It can be said that the most common origin in cushing syndrome or hyperadrenocorticism, among 80-85% of cases are usually a tumor or hypertrophy in the pituitary gland that secretes too much ACTH hormone that causes the adrenal to produce more cortisol than normal. Another less frequent way, between 15-20% of cases occur in the adrenal glands normally due to a tumor or hyperplasia. The iatrogenic origin is much less frequent.

It is vital that the cause of cushing syndrome be detected as quickly as possible. Obviously, an expert veterinarian must do it by performing various tests and prescribing the most appropriate treatment, which will depend entirely on the cause or origin of the syndrome.

Symptoms of cushing syndrome

As we have commented before, many of the easily visible symptoms can be confused with the typical symptoms of old age in a dog and, for this reason, many people do not realize that the signs and symptoms that their faithful friend presents are due to an abnormality in the production of cortisol or cushing syndrome. As the disease usually develops slowly, the symptoms will appear gradually, it may take months even years to appear. Keep in mind that not all dogs respond equally to an increase in cortisol, so it is very possible that not all dogs have all the symptoms.

Although there are more, most frequent symptoms of cushing syndrome They are as follows:

  • Increased thirst and urination
  • Increased appetite
  • Skin problems and diseases
  • Alopecia
  • Hyperpigmentation of the skin
  • Poor hair quality
  • Frequent gasps
  • Weakness and muscular atrophy
  • Lethargy
  • Obesity located in the abdomen (swollen belly)
  • Increase in liver size
  • Recurring skin infections
  • In an advanced case of pituitary origin, neurological changes will occur
  • Alterations in the female reproductive cycle
  • Testicular atrophy in males

Sometimes, the most direct way to realize that it is cushing syndrome is not its symptoms, but occurs when the veterinarian detects a secondary disease caused by it. For example, diabetes mellitus, secondary hypothyroidism, nervous and behavioral disorders, among other possibilities.

Predisposition in some dogs

This abnormality of the functioning of the adrenal glands, which causes an overproduction of cortisol, is more frequent in adult dogs than in young dogs, normally from 6 years and especially in dogs over 10 years. It can also affect dogs suffering from episodes of stress due to some other type of problem or with other related conditions. It seems that there are indications to think that the most frequent cases of cushing syndrome with pituitary origin occur in dogs of less than 20kg, however cases of adrenal origin are more frequent in dogs of more than 20kg, although the adrenal type is It also occurs in small dogs.

Although the sex of the dog does not influence the appearance of this hormonal syndrome, the breed seems to have a certain influence. These are some of the races with more propensity to suffer from cushing syndrome, depending on the origin of the problem:

Diagnosis and treatment for cushing syndrome

It is very important that if we detect any of the symptoms discussed in the previous section even though they may seem old to us, We go to our trusted veterinarian to perform all the tests you deem necessary to be able to rule out or diagnose the cushing syndrome in our hairy and can offer us the best solution and treatment.

The veterinarian should perform various tests such as blood tests, urine tests, skin biopsies in areas that present alterations, x-rays, ultrasound, specific tests to measure the concentration of cortisol in the blood and, if the pituitary origin is suspected, CT and resonance should be performed magnetic

The vet will prescribe us hemost indicated treatment that will depend entirely on the origin Have cushing syndrome in each dog. The treatment can be pharmacological for life or until the dog can be operated and should be based on regulating cortisol levels. The treatment can also be directly surgical to remove the tumor or solve the problem that occurs in the glands, whether adrenal or pituitary. Treatment based on chemotherapy or radiotherapy is also considered when the tumors are not operable. On the other hand, if the cause of the syndrome is an iatrogenic origin, it will be enough to interrupt the medication of the other treatment that is being given and that has been the cause of the cushing syndrome.

It will be necessary to consider many parameters of the dog's health and the probabilities in each case to decide if one treatment or another is better. In addition, we will have to make regular visits to the veterinarian to monitor cortisol levels and adjust medication if necessary or to control the postoperative process.

This article is purely informative, at we have no power to prescribe veterinary treatments or make any kind of diagnosis. We invite you to take your pet to the veterinarian in case he presents any type of condition or discomfort.

If you want to read more articles similar to Cushing syndrome in dogs - Symptoms and causes, we recommend you go to our Other health problems section.

What is Cushing's disease in dogs?

Cushing's syndrome owes its name to neurosurgeon Harvey Cushing, who was the first to discover this ailment in humans in 1912. In animals, it is a common endocrine problem in older dogs, especially after eight years or more. In fact, "after hypothyroidism, Cushing's syndrome is the second most common endocrine disease in dogs," says veterinarian Juan Antonio Zaldívar.

The most striking alert that the pet can suffer from Cushing's disease is that he begins to drink much more water and needs to pee very frequently

This medical condition, also known as the cortisol excess diseaseIt appears when the pet's adrenal glands produce cortisol hormone in an excessive amount. These glands are two small sacs located in each of the kidneys and responsible for producing important hormones dedicated to regulating essential body functions for the pet, among others, cortisol.

When the hormonal balance is broken, the problems begin. And that is precisely what happens to dogs with Cushing's disease. Your adrenal glands secrete an excessive amount of cortisol, and this causes your metabolism to turn upside down.

These are the signs of Cushing in the dog

The most striking warning that the pet may suffer from Cushing's disease is that he begins to drink much more water than usual and, consequently, needs to pee very frequently. "Almost all people go to the clinic when they detect that the dog drink more water and urine more and, in many cases, because the pet cannot stand and even urinates at home or at night, "explains veterinarian Carlos Melián.

But also, as the disease worsens, the dog can lose muscle, his general physical condition weakens and it may even be that your skin becomes thinner and therefore less able to protect you. It is also common for the pet to have more appetite and lose hair, especially on the sides, as well as the neck and perineal area (the area around your genitals and anus). "Also panting in a characteristic sign of Cushing syndrome in dogs, a frequent and especially significant symptom when panting even at rest," adds the expert.

The problem is that these signs usually appear slowly, which causes them to be confused with other ailments and go unnoticed as normal symptoms of can aging. Therefore, the advice, remember veterinarians, is to go to routine veterinary checks, which are every six months in older dogs.

Why does Cushing's disease appear?

Cushing's disease is more common when the pet is higher, and also when the dog is from small breed, as is the case with the beagle, the small terrier, the so-called sausage dogs and the yorkshire.

The most frequent cause of this syndrome in these animals is the appearance of a tumor Benign in your pituitary gland that triggers the production of the hormone. Other times, although less frequent, it can also happen that a tumor grows in one or both adrenal glands, and that this thickening is the one that directly develops the hormone cortisol. And there are even times that can arise when the pet is being medicated. Therefore, experts insist: to clearly detect the origin of this disease, it is essential to go to the veterinarian.

Cushing's syndrome treatment

The benign tumors responsible for Cushing's syndrome are usually quite small and are not often spread, so they do not usually cause physical problems of greater depth. The most common treatment consists of a medication that helps reduce cortisol production and return it to its normal levels.

Experts explain that, once the treatment begins, it is normal for the symptoms to gradually disappear and for the dog to regain his usual thirst.