Adrenal hyperfunction

What is adrenal hyperfunction?

Adrenal hyperfunction, also known as hyperadrenocorticism or Cushing's syndrome, is a condition in which the adrenal glands produce too much cortisol. Cortisol is a hormone that is involved in many metabolic processes and helps the body to deal with stress. However, if there is too much cortisol in the blood, it can lead to various health problems.

What are the causes of adrenal hyperfunction?

There are two main causes of adrenal hyperfunction in dogs:

• A tumor in the pituitary gland (hypophysis) that releases too much ACTH. ACTH is a hormone that stimulates the adrenal glands to produce cortisol. This is the most common cause and affects around 80-85% of affected dogs.
• A tumor in one or both adrenal glands that autonomously produces cortisol. This is the rarer cause and affects about 15-20% of affected dogs.

Another possible cause is the long-term administration of cortisone medication used to treat inflammation or allergies. This is known as iatrogenic Cushing's syndrome and can be remedied by stopping or reducing the medication.

What are the symptoms of adrenal hyperfunction?

The symptoms of adrenal hyperfunction can vary depending on the severity and duration of the condition. The most common symptoms are

• Increased thirst and urine output
• Increased hunger and weight gain
• Hair loss and thin coat
• Thin skin and a tendency to skin infections
• Muscle weakness and peritoneum
• Breathing difficulties and heart problems
• Behavioral changes such as lethargy, depression or aggression

How is adrenal hyperfunction diagnosed?

To diagnose adrenal hyperfunction, your vet will first need to perform a thorough clinical examination and take into account your observations of your dog's symptoms. They will then order some blood and urine tests to measure blood cortisol levels and rule out other conditions.

To determine the exact cause of the adrenal hyperfunction, your vet may perform further tests, such as

• The ACTH stimulation test, where your dog is given an injection of ACTH and then their cortisol response is measured.
• The dexamethasone suppression test, where your dog is given an injection of dexamethasone (an artificial cortisone) and then their cortisol suppression is measured.
• An ultrasound scan of the adrenal glands to detect a possible tumor.

How is adrenal hyperfunction treated?

The treatment of adrenal hyperfunction depends on the cause. If your dog has iatrogenic Cushing's syndrome, your vet will need to adjust or discontinue the dose or medication. If your dog has a pituitary tumor, he will need to take a medication that inhibits cortisol production. The most common medication is Trilostane, which is administered daily or twice daily. If your dog has an adrenal tumor, he will need surgery to remove the tumor. In some cases, radiotherapy or chemotherapy may also be required.

Treatment for adrenal hyperfunction requires regular monitoring by your vet to assess its effectiveness and potential side effects. Side effects may include loss of appetite, vomiting, diarrhea, weakness or hypofunction of the adrenal glands (Addison's disease). If you notice such signs in your dog, you should contact your vet immediately.

How can you help your dog with adrenal hyperfunction?

If your dog has adrenal hyperfunction, you can help him by:

• Administering his medication as directed by your veterinarian and not skipping or changing doses.
• Monitoring his symptoms and behavior and reporting back to your vet regularly.
• Provide him with a balanced diet of high quality protein and low fat to control his weight and promote his skin and coat health.
• Provide him with plenty of fresh water to quench his thirst and support his kidneys.
• Provide him with moderate exercise to strengthen his muscles and reduce his stress.
• Give him lots of love and care to improve his well-being.