Cushing's disease is a hormonal disorder of horses also known as hyperadrenocorticism. It is caused by a benign tumor of the pituitary gland (at the base of the brain) that results in over-production of cortisol and cortisol-like hormones. Cortisol is known as the 'stress' hormone and increases blood sugar levels, suppresses the immune system and is implicated in laminitis (founder).
Cushing's is the most common endocrine disorder diagnosed in horses and ponies. It is more common in horses over the age of 15, and some reports show that up to 25% of older horses will develop this disease.
Clinical signs are varied and subtle in the early stages, but can include failure to shed, a long wavy coat, swayback appearance, muscle loss, increased drinking, eating, and urination, lethargy, excessive sweating, abnormal fat deposition, recurrent infections, and chronic laminitis.
A variety of tests are available to assist in achieving a definitive diagnosis, especially in horses with subtle clinical signs. The dexamethasone suppression test and ACTH levels are the most commonly used diagnostic tests.
Although there is no cure for Cushing's disease, affected horses can be managed to live long healthy lives. Drug therapy and husbandry play an important role in the management of these horses. Treatment is necessary to reduce hormone release, to reduce clinical signs, and to reduce complications. Medications are often prescribed to treat the primary disease and the secondary complications that may be present at the time of diagnosis.
Management with diet modification and regular veterinary and farrier care is essential. Low carbohydrate diets are typically recommended. Each horse is an individual and assessment of condition, secondary diseases, and management factors is necessary to formulate an appropriate treatment plan.
The earlier the disease is diagnosed, the sooner appropriate diet and management changes can be implemented, and the better the disease can be controlled, which leads to a longer healthier life for your companion.
If you have concerns about your older horse, schedule an appointment to have our doctors evaluate them, 330.410.4899
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