Cushing's disease, or hyperadrenocorticism, is the overproduction of the steroid hormone cortisol. Dogs need natural steroids in order for their bodies to function properly. Cortisol is produced in the adrenal glands near the kidneys. The adrenal glands are controlled by the pituitary gland, which sits at the base of the brain.
If either of these glands develops a tumour, then an excess of cortisol is produced, which in turn causes the disease known as Cushing's. These tumours are usually benign (don't spread) but occasionally can be malignant cancers.
The majority of cases have a growth in the pituitary gland, but occasionally this can be in the adrenal gland. If a dog is given large doses of steroid drugs, this can also induce Cushing's disease.
How common is Cushing's disease in dogs?
Cushing's disease is diagnosed fairly frequently in middle-aged dogs. In the USA it is estimated that 100,000 dogs per year are diagnosed with Cushing's disease.
How did my dog get Cushing's disease?
Usually Cushing's disease is caused by a growth in either the adrenal or pituitary glands leading to increased cortisol steroid hormone production and circulation. Occasionally they may develop Cushing's due to being administered steroid drugs in high doses or if given long term. This form of Cushing's disease is known as Iatrogenic Cushing's.
What is the best treatment for Cushing's disease in dogs?
Treatment may depend on the underlying cause of Cushing's disease. If there is a tumour present, and no spread, surgery may be performed to remove the mass and cure your dog of Cushing's. This may also depend on any other problems your dog may have. If surgery is not an option for your dog, life-long medication will need to be prescribed by a vet. This will need to be closely monitored and adjusted with frequent blood tests. Radiation therapy may also be indicated to shrink a tumour. Most of the time treatment for Cushing's is to manage the disease not cure it.
Complications of Cushing's disease in dogs
Complications of Cushing's usually occur if a dog is not very well controlled on medication or undiagnosed. Most common complications include increased blood sugar levels (diabetes mellitus), high blood pressure, blood clots that can cause breathing problems (pulmonary thromboembolism), skin problems (including hair loss and infections), urinary tract infections and kidney problems, which will usually present as urinating more than usual.
Does Cushing's disease cause skin lesions on dogs?
Hair loss is common with Cushing's. This is often on both sides of the dog and generally means the hair will be thin all over. Skin also becomes thinner and dark spots may appear on the skin (hyperpigmentation). Skin infections and crusting are common, but this is not always itchy. Skin healing is poor and slower than normal. Calcinosis cutis is a skin condition where hard areas of skin form due to mineral deposits and, although this can appear independent of other problems, it is most often linked with Cushing's.
Does a dog's behaviour change with Cushing's disease?
Dogs with Cushing's may display aggression. They will be hungrier and thirstier, and therefore need to go out to the toilet more and will wake you in the night for this too. Dogs with Cushing's are often lethargic and not able to exercise as much as they used to. They also pant a lot more than normal. Occasionally they also have difficulty getting up the stairs.
What do you feed a dog with Cushing's disease?
Your dog should be fed a complete diet as recommended by a veterinary surgeon. Ideally the diet should be low in fat, contain moderate fibre, low salt and highly digestible protein. The diet may need to be tailored to the individual dog's needs.
Is there pain with Cushing's disease?
Generally speaking Cushing's isn't a painful condition. Untreated, the dog may be uncomfortable due to side effects of the disease process. With medication and regular monitoring, your dog should he kept very comfortable and happy.
Is shaking a symptom of Cushing's in dogs?
Muscle wastage is a common problem associated with Cushing's disease. This can lead to weakness and shaking, but is uncommon. But if your dog is on treatment for Cushing's and starts shaking, seek urgent veterinary attention as the drugs may be causing the reverse of Cushing's and be causing hypoadrenocorticism (or Addison's disease). Addison's disease can be rapidly life-threatening, so prompt medical treatment is required.
Is treating Cushing's disease in dogs expensive?
There are significant ongoing costs with treating Cushing's disease. The medication itself will be daily and lifelong. Apart from paying for the medication, you will need regular check-ups with the vet and ongoing monitoring of treatment with blood tests.
Can Cushing's in dogs be treated naturally?
No. While some complementary therapies may help with some symptoms and make your dog more comfortable, the only way to successfully manage Cushing's disease is with medication or surgery under the guidance of a veterinary surgeon.
What happens if Cushing's is left untreated in dogs?
If a dog is left untreated for Cushing's the symptoms will worsen until the dog is so poorly it needs euthanising or dies of complications to the disease (such as blood clots on the lungs – pulmonary thromboembolism). But this would usually progress slowly, so the dog may still live a couple of years untreated with the disease, albeit with side effects. If a blood clot develops and moves into the lungs, this would usually present as a rapid deterioration in breathing, struggling to breathe or even sudden death.
What are the final stages of Cushing's disease in dogs?
If Cushing's disease is untreated, poorly controlled or doesn't respond to treatment, this will lead to dogs becoming very lethargic, pot bellied, unable to exercise and depressed. Skin will be cold to the touch, especially at the extremities. Hair and skin condition will be poor. Increased drinking and excessive urination will be seen. From having a good appetite early in the disease process, appetite will probably reduce or your dog may even stop eating.
What is the life expectancy of a dog with Cushing's disease?
While dogs can live many years controlled on medication for Cushing's, the general life expectancy is around three years.
Can a dog die from Cushing's disease?
If untreated it is possible for a dog to die from the consequences of Cushing's disease. Treatment for Cushing's is generally based upon management and not cure, and so eventually your dog will die or have to be euthanised because of the condition.
When to euthanise a dog with Cushing's disease
Once clinical signs are affecting your dog's daily life and the quality of life is impacted, then it is a good idea to discuss with a vet about end-of-life care. If the condition doesn't control well on treatment or if you can't afford treatment, then euthanasia may be the most humane decision.
When should I see a vet?
If you notice any changes in your dog's behaviour, appetite, thirst, energy levels or overall condition, it is recommended that you seek advice from a veterinary surgeon.