Dog Cushing’s Disease Syndrome Symptoms and Treatments

Cushing's can occur in dogs from about ten years old through to old age and in its early stages is often mistaken for signs of ageing or even interpreted as signs of other diseases.

In the normal dog, the adrenal glands secrete cortisone, a hormone responsible for the normal function of many of the body's organs and important in the management of stress. The pituitary, a small pea-sized gland situated in the base of the brain, secretes adrenocorticotrophic hormone (ACTH) which stimulates the adrenal glands to produce cortisone.

In Cushing's Disease a tiny non-malignant growth in the pituitary will increase the secretion of ACTH, which results in too much cortisone being secreted by the adrenals, whereas in Cushing's Syndrome an adrenal tumour, either malignant or benign, will result in an over-production of cortisone to the extent that the ACTH cannot cope with the amount circulating in the blood.

The signs of either of these forms of Cushing's are difficult to detect in the early stages, but one of the earliest indications is hair loss. Other signs are a massively increased thirst and what might seem like 'accidents' with the dog urinating more frequently than usual. His appetite will increase and he may start scavenging; his abdomen will take on a 'pot-bellied' look and he will put on weight. He will gradually lose his energy and personality, becoming slower and not less alert. He'll appear to be overheating and will find cool surfaces to lie on, and will pant more.

One oddly beneficial side effect is that if a dog has been suffering with degenerative or inflammatory changes such as arthritis the higher level of cortisone in the blood will actually relieve his pain and discomfort.

Diagnosis is often delayed because of the slow onset. Diagnosis is tricky, although high blood cortisone levels are a good indication that Cushing's may be present. Scans may not always show soft tissue tumours especially in the pituitary where a growth can be as small as 3mm in diameter.

Once diagnosis has been made, treatment is usually medication based, particularly if a dog is elderly. Surgical removal of adrenal tissue tends only to be performed in dogs who are otherwise fit and have been diagnosed early, although if the tumour is malignant it is not thought to be an option since by the time of diagnosis it has probably spread to other organs. Pituitary tumours are not removed and can be managed conservatively with medication.

There are several drugs which can be used to treat Cushing's, and it is important to discuss the treatment and side effects with your vet. Each carries its own risks and side effects and choice of medication will depend on severity of the condition and the size and breed of dog, although recent developments are leading to partial and sometimes total recovery in under six months.

Choosing not to treat a dog will usually result in his being severely debilitated to the extent that your vet may suggest that he is euthanised, particularly if his physical symptoms are too distressing for a sick dog to cope with.

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