Cushing’s disease, also known as ‘Hyperadrenocorticism’, is one of the most common hormonal diseases of older dogs. The disease is characterised by an excessive production of cortisol.
Clinical Signs
Dogs with Cushing’s tend to:
- Gain weight – often with a pot belly
- Have excessive thirst and hunger
- Urinate excessively
- Pant and puff more
- Have thin skin with hair loss and often repeated skin infections
Increased production of cortisol causes:
- Sudden ageing
- Fatty deposits in the liver
- Weakening of muscle and connective tissue
- High blood pressure
- High cholesterol
- Suppression of the immune system
- Eye damage
Treating Cushing’s disease is very rewarding as these sudden signs of ageing can be rapidly reversed. It is however a disease that needs complex blood tests to diagnose and then monitor treatment. You will also need to give your dog a pill every morning for the rest of it’s life.
Diagnosis
Cushing’s disease is often suspected from markers at a routine blood profile.
Markers such as a raised ALKP and Cholesterol along with physical changes in your dog will prompt us to suggest a screening test.
Animals with Cushing’s are more likely to develop urinary tract infections, so an examination of urine is useful when your pet is diagnosed and monitored.
The initial screening test is called a Low Dose Dexamethasone Suppression test. To perform this test your pet is hospitalised for the day, given a very low dose of dexamethasone intravenously and blood is taken at 0,4 and 8 hours. The result of the test will indicate to us if your dog has Cushing’s and would benefit from treatment. Sometimes the result is inconclusive. These dogs often develop the condition with time, so are monitored closely.
If the result is positive, your dog is likely to have Cushing’s disease. You may then need a second blood test called the ACTH Stimulation Test, which is sometimes needed to differentiate between pituitary and adrenal dependent Cushings disease. This test can indicate if your dog will respond to oral treatment, or we may suggest that an abdominal ultrasound needs to be performed for further information.
If your dog has Trilostane responsive Cushing’s Disease we can then start daily medication with a tablet given with food every morning. The dose of medication varies for each dog and it is really important to ensure that your dog is on the correct dose of medication. To ensure your dogs medication level is correct, an ACTH Stimulation Test is performed at 10 and 28 days after starting medication. Some dogs are more difficult to predict the correct dose of Trilostane and may need additional tests.
The timing of the monitoring ACTH Stimulation Test is very important. We need you to have given the medication as usual and then the blood test is performed 4 hours after the medication has been given. This is necessary to get accurate results.
Once your dog is on the correct dose of medication we will then do a monitoring ACTH Stimulation Test every 3 months to make sure the Trilostane dose remains correct. This is very important as the wrong dose of medication could lower the cortisol levels to a dangerous level, and put the body into crisis.
We recommend that dogs on Trilostane have a medication review with comprehensive blood profile twice yearly, once the condition is stabilised, in addition to the 3 monthly ACTH stimulation tests. This is to ensure we pick up any other changes that may be occurring in the body which may affect treatment.
Dogs with Cushing’s Disease that are well controlled with a daily Trilostane tablet will often have vastly improved health and quality of life. They will live longer, have a healthier immune system and be happier. It is however a big financial and time commitment for the owner. This is usually so rewarding when you see your pet improve.
Don’t hesitate to ask us for a comprehensive estimate of blood test and medication charges.
Advice for caring for an unwell or elderly pet.
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