Cushing’s disease, named after the first physician who reported it, results from excess cortisol in the body.
It is most common in middle-aged to older dogs. The most susceptible breeds include:
- Poodles
- Dachshunds
- Boston Terriers
- Boxers
- Beagles
Introduction
Cortisol is a corticosteroid hormone that controls metabolism and response to stress.
It is produced by the adrenal glands, which are found on top of the upper part of the kidneys. The adrenal glands produce cortisol in response to another hormone secreted by the pituitary gland.
The pituitary gland is found in the brain. It is the master gland because it secretes a number of hormones that act elsewhere in the body, telling other organs to release additional hormones.
A tumor in the pituitary gland or the adrenal glands can lead to too much cortisol and Cushing’s disease.
What does it look like
Common signs include excessive water drinking and urinating. In addition, dogs often develop a “pot-bellied” appearance. That happens because cortisol thins the abdominal muscles, allowing the belly to sag and increasing the size of the liver. Other common signs include:
- hair loss (symmetrical)
- skin rashes
- darkened or thickened skin
- weakness
- sluggishness
- wounds that don’t heal well
Typical symptoms
- Drinking a lot of water
- Urinating more than usual
- Pot-bellied appearance
- Hair loss
- Dark or thickened skin
- Slow-healing wounds
- Weakness
- Sluggishness
Diagnosing Cushing’s disease
Diagnosis includes tests to measure blood levels of cortisol under various conditions.
A series of blood samples is needed on a defined schedule (every 1-2 hours). In addition, dogs usually need to stay in the veterinary hospital for the day.
How is it treated
Treatment aims to decrease the amount of cortisol in the body.
Available medications either:
- destroy part of the adrenal gland (and so decrease the production of cortisol)
- or that counteract the hormone sent out by the pituitary gland. This prevents the adrenal glands from producing too much cortisol in the first place.
Drug-induced Cushing’s
Cushing’s disease can also develop in dogs receiving long-term corticosteroid medications for other problems.
These medications act the same way that cortisol does. Therefore, their side effects include the same signs, i.e., drinking a lot of water, urinating frequently, etc.
If your dog has been on corticosteroids long-term, it is essential to discontinue them gradually. That gives the body time to adjust to regulating its metabolism again.
Your veterinarian will work with you on a program to gradually decrease your dog’s dosage of corticosteroid medication.
Related articles:
The Function of Cortisol: What Happens In A Dog’s Body When It Goes Awry?
Dog Adrenal Hormones: What is the Difference between Adrenaline and Cortisol?
Further reading:
Cushing’s Disease in Dogs