Cushing's Disease in Dogs

Cushing's Disease in Dogs

Cushing’s disease, or hyperadrenocorticism, is a hormonal disorder in dogs that occurs when the adrenal glands overproduce cortisol, a hormone that helps regulate stress, immune response, and metabolism. While cortisol is essential for health, an excess can lead to serious health problems. Cushing’s disease is most commonly caused by either a tumor in the pituitary gland or, less frequently, a tumor in one of the adrenal glands. It primarily affects middle-aged and older dogs.

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What Causes Cushing’s Disease in Dogs?

Cushing’s disease can be caused by different factors, and understanding the cause is essential for determining the appropriate treatment. There are three main types of Cushing’s disease in dogs:

Pituitary-Dependent Cushing’s Disease (PDH):

This is the most common form, affecting about 85-90% of dogs with Cushing’s disease.

It occurs when a benign tumour forms in the pituitary gland, located at the base of the brain. This tumour causes the pituitary gland to signal the adrenal glands to overproduce cortisol.

Adrenal-Dependent Cushing’s Disease (ADH):

This form accounts for about 10-15% of cases.

It happens when a tumor, either benign or malignant, develops directly in one of the adrenal glands, leading to excess cortisol production.

Iatrogenic Cushing’s Disease:

This is caused by long-term or excessive use of corticosteroid medications prescribed for conditions like allergies or immune diseases.

When the dog stops taking these medications, symptoms of Cushing’s disease typically disappear.

What Are the First Signs of Cushing’s Disease?

The early signs of Cushing’s disease can be subtle, making it difficult for pet owners to detect the problem right away. However, as the disease progresses, the symptoms become more noticeable. Early signs include:

  • Increased thirst: Dogs may start drinking a lot more water than usual.
  • Frequent urination: You might notice your dog needing to go outside more often or even having accidents indoors.
  • Increased appetite: A dog with Cushing’s disease may show an unusually ravenous appetite.
  • Excessive panting: Even when resting, your dog may pant heavily.
  • Behavioral changes: Dogs may become more restless or show signs of anxiety.

Recognising these early signs is key to ensuring early diagnosis and treatment.

How is Cushing’s Disease Diagnosed in Dogs?

Diagnosing Cushing’s disease can be complex because many of its symptoms mimic other conditions, such as diabetes or kidney disease. Here’s how vets usually diagnose it:

Initial Examination:
The vet will start by reviewing your dog’s symptoms and medical history. A physical exam will be done to check for common signs like a pot-bellied appearance, hair loss, or thinning skin.

Blood and Urine Tests:
A complete blood count (CBC) and urinalysis are often the first tests ordered. Dogs with Cushing’s disease often show elevated liver enzymes and cholesterol levels.

Specialised Hormone Tests:
ACTH Stimulation Test: This test measures how the adrenal glands respond to adrenocorticotropic hormone (ACTH). It helps to confirm Cushing’s disease but may not distinguish between pituitary and adrenal types.

Low-Dose Dexamethasone Suppression Test (LDDST): This test helps differentiate between pituitary-dependent and adrenal-dependent Cushing’s. It involves giving a low dose of dexamethasone (a steroid) and checking cortisol levels at intervals over several hours.

Imaging:
Ultrasound or MRI may be recommended to look for tumours in the adrenal glands or pituitary gland.

What Are the Common Symptoms of Advanced Cushing’s Disease in Dogs?

As Cushing’s disease progresses, the symptoms become more pronounced. In advanced stages, you may notice:

  • Hair loss: Patches of hair may start to fall out, often symmetrically along the sides of the body.
  • Thinning skin: The skin may become thin and prone to bruising or infection.
  • Pot-bellied appearance: The dog’s abdomen may become distended due to muscle weakness and an enlarged liver.
  • Lethargy: Affected dogs often become less active, with noticeable muscle weakness.
  • Frequent skin infections: Dogs with Cushing’s disease may develop recurring bacterial or fungal infections due to a weakened immune system.

These symptoms can significantly impact a dog’s quality of life if left untreated. 

How is Cushing’s Disease Treated?

The treatment for Cushing’s disease depends on the underlying cause:

Pituitary-Dependent Cushing’s Disease (PDH):

  • This form is usually treated with medications like Trilostane (Vetoryl) or Mitotane, which help reduce the production of cortisol.
  • Regular monitoring and blood tests are required to adjust the medication dose and prevent side effects like vomiting, diarrhoea, or adrenal gland suppression.

Adrenal-Dependent Cushing’s Disease (ADH):

  • If the tumour is benign, surgery to remove the affected adrenal gland is often the best option.
  • In cases where the tumour is malignant or surgery is not an option, medication may be used to manage the condition.

Can Cushing’s Disease Be Cured in Dogs?

Unfortunately, Cushing’s disease cannot usually be fully cured, especially in cases of pituitary-dependent Cushing’s. However, with proper management, the symptoms can be controlled, and many dogs go on to live happy, healthy lives for several years.

For adrenal-dependent Cushing’s, surgery may offer a cure if the tumour is benign and can be completely removed.

How Long Can a Dog Live with Cushing’s Disease?

The life expectancy of a dog with Cushing’s disease varies depending on factors such as the type of Cushing’s, the age of the dog, and the success of the treatment.

  • Pituitary-dependent Cushing’s: Dogs typically live 2-3 years after diagnosis, though many live longer with proper management.
  • Adrenal-dependent Cushing’s: If the tumour is removed successfully, a dog may live for 18 months to 2 years, or even longer if the tumour is benign.

    • Regular monitoring and following the vet’s recommendations are key to prolonging a dog’s life.

    Are Certain Dog Breeds More Prone to Cushing’s Disease?

    Yes, certain breeds are more genetically predisposed to developing Cushing’s disease, particularly pituitary-dependent Cushing’s. These breeds include:

  • Poodles (Miniature and Toy)
  • Dachshunds
  • Boston Terriers
  • Beagles
  • Boxers
  • Staffordshire Bull Terriers

    • Older dogs are more likely to develop Cushing’s disease, with most cases occurring in dogs aged 6 years and older.

    What Happens if Cushing’s Disease is Left Untreated?

    If left untreated, Cushing’s disease can lead to a number of serious complications:

    • Diabetes: Prolonged high cortisol levels can cause insulin resistance, leading to diabetes.
    • High blood pressure: Elevated cortisol can increase blood pressure, which strains the heart and kidneys.
    • Weakened immune system: This makes dogs more prone to infections, particularly urinary tract infections and skin infections.
    • Muscle wasting and weakness: Over time, the dog may experience significant muscle atrophy, especially in the hind legs.

    Ultimately, untreated Cushing’s disease can be life-threatening, so prompt diagnosis and treatment are crucial.

    Is Cushing’s Disease Painful for Dogs?

    Cushing’s disease itself is not typically painful. However, the complications associated with the disease, such as muscle weakness, infections, or high blood pressure, can cause discomfort. With proper treatment, most dogs are able to live comfortably.

    What is the Cost of Treating Cushing’s Disease in the UK?

    The cost of treating Cushing’s disease in dogs in the UK can vary based on the treatment options, the frequency of monitoring, and your location. Here’s a breakdown of typical expenses:

    Diagnosis Costs:
    Initial blood tests, such as the ACTH stimulation test or low-dose dexamethasone suppression test, typically cost between £150 and £300.

    Additional diagnostic tools like an abdominal ultrasound may cost around £200 to £500, depending on the veterinary practice.

    Medication Costs:
    The most commonly prescribed medication, Trilostane (Vetoryl), costs approximately £40 to £80 per month depending on the dosage required and the size of the dog. Dogs will need regular medication throughout their lives.

    Regular Monitoring:
    Dogs with Cushing’s disease require regular blood tests, usually every 3 to 6 months, to monitor cortisol levels and adjust medication. Follow-up blood tests can cost between £100 and £300 per visit.

    Surgery:
    If surgery is needed to remove an adrenal tumour, the costs can be significant, often ranging from £1,500 to £3,000 depending on the complexity of the surgery and whether the tumour is benign or malignant.

    Ongoing Care:
    Ongoing management, including additional medications for symptoms or complications, can add to the cost. Budgeting for at least £500 to £1,000 annually for continued care and monitoring is advisable.

    While costs can be considerable, pet insurance may cover part of the treatment depending on the policy. Always consult with your vet for a detailed cost breakdown specific to your dog’s condition and treatment plan.

    Can Dietary Changes Help Manage Cushing’s Disease?

    Yes, dietary changes can help manage some of the symptoms of Cushing’s disease. A well-balanced, high-protein diet with limited carbohydrates is often recommended to support muscle mass and manage weight gain. A diet low in sodium can also help with high blood pressure. Always consult your vet before making dietary changes for a dog with Cushing’s disease.

    Can Cushing’s Disease Lead to Other Health Problems Like Diabetes?

    Yes, dogs with Cushing’s disease are at higher risk of developing other health problems. One of the most common is diabetes, due to cortisol-induced insulin resistance. Other complications include high blood pressure, urinary tract infections, and muscle wasting.

    How Often Should a Dog with Cushing’s Disease Be Monitored by a Veterinarian?

    Dogs with Cushing’s disease require regular monitoring to ensure that their treatment is working effectively and to adjust medication doses as needed. Typically, dogs will need to be seen by a veterinarian every 3-6 months for follow-up blood tests and exams. Monitoring helps catch any side effects early and ensures the disease is well-managed.

    Cushing’s disease is a complex condition that affects many middle-aged and older dogs, particularly certain breeds like Poodles, Dachshunds, and Beagles. While it cannot always be cured, early detection and proper management through medications or surgery can help dogs live comfortable, happy lives. If you notice any symptoms of Cushing’s disease in your dog, such as increased thirst, urination, or hair loss, consult your veterinarian to discuss diagnostic tests and treatment options.

    For any further help and advice please contact us on 01484 246420 and why not join our social media channels and online community on Instagram, Facebook or TikTok.

    With Wags and Woofs,

    Laura, Dolly, Reggie & Bear

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