Cushing’s Disease in Dogs
Symptoms, Diagnosis and Long Term Management
Cushing's disease (hyperadrenocorticism) is a common hormonal condition in dogs caused by prolonged exposure to excessive levels of cortisol. It most often affects middle aged and older dogs and usually develops gradually over time.
Cortisol plays an important role in regulating metabolism, immune function, blood pressure and the body's response to stress. When cortisol levels remain elevated for extended periods, multiple body systems can be affected.
Although Cushing's disease is a chronic condition, many dogs can continue to enjoy a good quality of life when the condition is appropriately managed and monitored by a veterinary surgeon.
What Causes Cushing's Disease?
Pituitary Dependent Cushing's Disease
This is the most common form of Cushing's disease, accounting for approximately 80 to 85 percent of cases. It occurs when a small tumour within the pituitary gland causes excessive stimulation of the adrenal glands, leading to increased cortisol production.
Adrenal Dependent Cushing's Disease
This form develops when a tumour within one of the adrenal glands produces excessive cortisol independently.
Iatrogenic Cushing's Disease
In some cases, signs similar to naturally occurring Cushing's disease can develop following prolonged exposure to corticosteroid medications prescribed for other medical conditions.
Common Signs of Cushing's Disease
The signs of Cushing's disease often develop slowly and may initially be mistaken for normal ageing.
- Increased thirst
- Increased urination
- Increased appetite
- Panting
- Weight gain
- Hair loss
- Thinning coat
- Thin skin
- Recurrent skin infections
- Pot bellied appearance
- Muscle wasting
- Reduced activity levels
Many affected dogs develop several of these signs simultaneously rather than experiencing a single isolated symptom.
How is Cushing's Disease Diagnosed?
No single test can diagnose every case of Cushing's disease. Veterinary surgeons typically combine clinical history, physical examination findings and diagnostic testing to reach a diagnosis.
Blood Testing
Routine blood tests may identify changes that raise suspicion of Cushing's disease and help assess overall health.
Hormone Testing
Specialised hormone tests may be recommended to assess cortisol regulation and support the diagnosis.
Urine Testing
Urine testing may be used as part of the diagnostic investigation and can provide additional information about urinary health.
Diagnostic Imaging
Ultrasound or advanced imaging may be recommended to evaluate the adrenal glands and investigate possible underlying causes.
Managing Cushing's Disease
Cushing's disease is generally considered a long term condition requiring ongoing veterinary care.
The goals of management are to improve quality of life, reduce the impact of clinical signs and monitor for complications associated with excessive cortisol production.
The most appropriate management approach depends on the underlying cause of the disease, the severity of clinical signs and the individual dog's overall health status.
For many dogs, veterinary surgeons may prescribe medication containing the active substance trilostane to help manage excessive cortisol production. Treatment must be individually assessed, prescribed and monitored by a veterinary surgeon.
Other management options may be considered in selected cases, particularly where an adrenal tumour is involved. Your veterinary surgeon will advise on the most appropriate approach for your dog.
Monitoring and Follow Up
Regular veterinary monitoring is an important part of managing dogs diagnosed with Cushing's disease.
Follow up appointments may include clinical examinations, blood testing, urine testing and assessment of changes in thirst, appetite, activity levels and overall wellbeing.
Dogs receiving trilostane will typically require regular monitoring to help ensure that cortisol levels remain appropriately controlled and to assess their ongoing response to treatment.
Monitoring helps assess how the condition is progressing and allows veterinary surgeons to identify potential complications as early as possible.
Long Term Outlook
The long term outlook varies depending on the underlying cause of the disease, the dog's age and any concurrent health conditions.
Many dogs with Cushing's disease continue to enjoy a good quality of life for years following diagnosis when appropriate veterinary care and monitoring are maintained.
Regular reassessment remains important because the condition can change over time.
When Should You Speak to Your Vet?
If your dog develops increased thirst, increased urination, changes in appetite, hair loss, abdominal enlargement, recurrent skin problems or unexplained behavioural changes, veterinary assessment is recommended.
Because the signs often develop gradually, early investigation can help identify underlying health conditions and guide appropriate management.