Cushing's Disease in Dogs
Causes, Symptoms, Treatment, and Prevention
Dogs can suffer from many of the same metabolic diseases humans do. One such disease is Cushing’s Syndrome, or hyperadrenocorticism.
Cushing Disease in dogs commonly manifests as excessive thirst and urination, but is often left undiagnosed due to the complex testing required to confirm the condition.
Dog Breeds Most Affected:
This condition affects some breeds of dogs more than others; The breeds most prone to Cushing’s Disease include Staffordshire Terriers, Boston Terriers, Yorkshire Terriers, Poodles, Dachshunds, and German Shepherds.
What is Cushing's Disease in Dogs?
Cushing’s Syndrome, or Cushing’s Disease, is a metabolic condition caused by an overproduction of cortisol, the stress hormone.
Cortisol plays a vital role in regulating essential processes like immune response, metabolism, blood pressure, sugar levels, and inflammation. Like all things, an abundance of cortisol can cause problems.
The abundance of cortisol is medically known as hypercortisolism or hyperadrenocorticism in dogs. This condition is most common in middle-aged to older dogs.
What Causes Cushing's Disease in Dogs?
The causes of Cushing’s Disease in dogs include:
• Pituitary Tumor
This type of Cushing’s Disease is more common, affecting about 80-90% of all animals with Cushing’s.
Cortisol secretion is stimulated by the adrenocorticotropic hormone (ACTH) secreted by the pituitary gland at the base of the brain.
A tumor of this gland results in overproduction of ACTH, causing Pituitary-dependent Cushing’s Disease. These tumors are usually benign and small but can lead to neurological symptoms as they grow.
• Adrenal Tumor
This type of Cushing’s disease affects 15% of all diagnosed dogs.
The adrenal glands on top of the kidneys are responsible for cortisol secretion. A tumor of these glands results in excessive cortisol, causing Adrenal-dependent Cushing’s disease.
The adrenal gland tumor can be either benign or malignant, although benign tumors are more common.
• Prolonged Use of Steroids
Prolonged excessive use of steroids like prednisone and dexamethasone can also cause Cushing’s Disease. This is known as Iatrogenic Cushing’s Disease.
Its symptoms are identical to Cushing’s Disease caused by tumors, but tend to resolve once the steroids are stopped.
Symptoms of Cushing's Disease in Dogs
Cushing’s Disease can be quite tricky to diagnose. So keep an eye out for these signs of Cushing’s Disease in dogs to make the process easier for you and your vet.
• Increased Thirst
Increased or excessive thirst is a common symptom of Cushing Disease in dogs. Increased thirst in this case is due to the excessive cortisol causing frequent urination.
• Increased Urination
Overproduction of cortisol causes increased and frequent urination. This is the hormone’s effect on the body. This increased urination is medically known as polyuria.
• Excessive Appetite
Cortisol stimulates appetite and hunger in both dogs and humans. So, excessive cortisol results in excessive appetite and weight gain.
A dog owner may notice their dog with Cushing’s Disease trying to access extra food from the kitchen or trash can in addition to other symptoms.
• Reduced Activity
Too much cortisol causes fatigue and lethargy, making reduced activity a frequently observed sign of Cushing’s Disease in dogs.
Cushing’s syndrome causes increased liver size, excessive fat deposition around the chest and abdominal cavity, and weakness of the muscles of respiration. All these combine to make breathing difficult, resulting in excessive panting.
• Thin and Fragile Skin
Excessive cortisol production causes the dog’s skin to thin and more fragile. As a result, dogs with Cushing’s Disease may bruise easily.
• Hair Loss
Cushing’s syndrome also leads to hair loss and alopecia. The fur that is left becomes dry, dull and brittle. This thinning most commonly affects the trunk, or torso, of a dog, sparing the head and the limbs.
• "Pot-Bellied" Abdomen
The muscles of the abdominal wall become weaker, resulting in a protruding or pot-bellied abdomen. This is made worse by an enlarged liver and increased abdominal fat in dogs with Cushing’s Disease.
• Muscle Weakness
Elevated cortisol levels cause muscle weakness and atrophy. As a result, a dog’s muscles can break down, causing the dog to appear thin in the limbs and large around the belly.
• Chronic Skin Infections
As Cushing’s syndrome makes the skin weaker, spontaneous skin infections become more common. Wounds will also take longer to heal if your dog has Cushing’s Disease.
How to Treat Cushing's Disease in Dogs
Treatment for Cushing’s Disease in dogs depends heavily on the underlying cause. Your main treatment options include:
Both pituitary and adrenal tumors can be treated via surgery. Surgical removal is more common in cases of adrenal-dependent Cushing’s Disease. For pituitary-dependent Cushing’s Disease, surgery is not as widely available.
Adrenal tumors require major abdominal surgery, which may cure the dog if the tumor is benign and entirely removed. In cases like these, your dog’s cortisol levels will return to normal after surgery, allowing them to enjoy a healthy life.
The only way to truly cure Cushing’s Disease is surgery, but due to the risks and complexity of surgery, medication is more commonly used to treat Cushing’s Disease. Vetoryl and Anipryl are the only FDA-approved medications for Cushing’s Disease in dogs, although sometimes Lysodren is used.
Trilostane or Vetoryl for dogs is used to treat both pituitary- and adrenal-dependent Cushing’s Disease. As it stops the production of cortisol in the adrenal glands, Vetoryl’s side effects include reduced appetite, vomiting, lack of energy, diarrhea, weakness, etc.
Anipryl or Selegiline are used to treat uncomplicated, pituitary-dependent cases of Cushing’s Disease.
Another way to treat Cushing Disease in dogs is via radiation. Radiation therapy for pituitary-dependent Cushing’s Disease can improve and even eliminate neurological symptoms, drastically improving a dog’s condition. This is especially true if the tumor is diagnosed and treated early.
• Discontinuation of Steroids
In iatrogenic Cushing’s Sydrome (ICS), the treatment is to gradually taper down and discontinue the steroid causing the disease. This should be done carefully and in some cases may result in a recurrence of the primary disease the steroid was used to treat.
• Natural Remedies
With your vet’s approval, you can also try some at home treatments for Cushing’s Disease in dogs. These home remedies can help in detoxification and normalizing the adrenal output of cortisol.
One such well-known remedy is Dandelion. Dandelion acts as a tonic for the liver, kidneys, and adrenal glands and helps normalize abnormal adrenal function.
Another natural remedy is Burdock. This cleansing herb detoxifies the tissues and helps the body remove any unwanted substances.
Other than these, some natural remedies are used for treatment of the symptoms caused by Cushing’s Disease. Arsenicum treats excessive thirst, while Hepar Sulph helps heal irritated skin. Sulfur improves the overall condition of your dog’s skin.
When to Euthanize a Dog with Cushing's Disease?
Euthanization can be a very difficult topic. Choosing to put your dog down is always hard, but can sometimes be inevitable. For example, when a dog is suffering from terminal canine Cushing’s Disease, it may be time to consider euthanizing your dog with the help of a vet. Here’s what you may take into account when making the difficult decision to euthanize.
Cushing’s disease in dogs can be very painful. If your dog’s condition gets to a point where they are in constant pain, you might want to consider euthanasia to ease their suffering.
• Breathing Problems
Cushing often causes breathing problems as the tumor progresses. If your dog starts to suffer from severe breathing issues, it may be time to make a vet appointment to discuss euthanasia.
• Inoperable Tumor
Sometimes your pet’s tumor is inoperable with no viable treatment options available. In such a case, euthanasia can be the best option to avoid further pain and suffering.
• No Response to Treatment
Cushing’s Disease is tricky to treat, and sometimes a dog just doesn’t respond to the available medication and therapies. Euthanasia could be your only available option if your dog’s condition does not improve with other treatment.
• Poor Quality of Life
If your dog’s quality of life has decreased drastically due to Cushing’s, you should consider euthanasia. Signs of poor quality of life are pain, discomfort, and inability to engage in and enjoy usual activities.
• Renal Failure
Cushing’s Syndrome often leads to kidney disease and failure. Renal failure is very difficult and painful to treat, so if your dog’s kidneys fail, euthanasia might be the most humane option.
5-10% of dogs with Cushing’s Disease develop diabetes over time. These dogs’ bodies stop producing insulin, and they will need life-long insulin injections. Diabetes combined with other complications of Cushing’s Disease can result in a lot of unnecessary suffering for your dog.
Seizures are a common neurological sign of Cushing’s in dogs. Seizures are seen in dogs suffering from pituitary-dependent Cushing’s Disease and can drastically reduce your dog’s quality of life.
• Refusal to Eat
A terminally ill dog may start refusing food and water and will slowly die from starvation if you can’t force-feed them. In such a case, your vet might recommend euthanasia to prevent suffering.
• Weight Loss
The excess of cortisol in Cushing’s Disease can lead to sudden weight loss in dogs. Such weight loss usually only happens when your dog is close to death, so euthanasia may be the only option left in this case.
How to Prevent Cushing's Disease in Dogs
There is no known way to prevent Cushing’s Disease in dogs caused by pituitary or adrenal tumors. However, you can reduce the chances of your dog developing iatrogenic Cushing’s Disease by avoiding long-term use of steroids.
Avoid all types of corticosteroid medication if possible. If not, be sure to carefully follow your vet’s instructions and check in with your vet regularly.
Cushing’s Disease may be a difficult journey for you and your dog. In some cases, surgery may lessen your dog’s symptoms and even cure your dog. Always follow your vet’s advice when administering medications and make a vet appointment if anything seems odd with your dog’s body or behavior.