Text Box: Equine Cushing’s disease A small benign tumour in the pituitary gland causes equine Cushing’s disease. Cushing's disease can also be referred to as hyperadrenocorticism. A horse with Cushing’s usually develops the condition in the mid to late years of life (average age, 20 years), although it is sometimes diagnosed in horses as young as seven.  It has been suggested that Cushing’s syndrome may sometimes be attributed to abnormal HSD activity within the cells. Increased HSD activity in the cells leads to increased cortisol within the tissues. This increase is believed to give rise to clinical signs of Cushing's syndrome. The most common symptoms of Cushing’s syndrome are: · Sudden-onset polydipsia (drinking large amounts). An affected horse may drink as much as 80 litres of water a day (as opposed to an average of 20 – 30 litres). · Polyuria (excessive urinating). · Abnormal hair growth and shedding. Affected horses may develop a growth of heavy, coarse, often curly hair, which does not shed in the summer. · Filling above the eyes caused by the deposition of fat. · A general appearance of malaise, with dull eyes and drab coat. · Increased appetite (usually with no accompanying weight gain). Chronic laminitis. In order to confirm a diagnosis of Cushing's disease, specific hormone tests are normally undertaken. While the symptoms of Cushing's syndrome are attributed to excessive production of cortisol by the adrenal glands, the level of cortisol in the blood varies throughout the day. This makes it difficult to differentiate between levels of cortisone concentration in the normal horse and a horse with Cushing’s syndrome. High cortisol levels interfere with the action of insulin, causing elevated insulin levels in horses with Cushing's syndrome. Some veterinarians therefore also measure insulin to support their diagnosis. Blood and urine tests are normally employed to diagnose Cushing’s disease. Once a positive diagnosis has been reached, appropriate treatment can begin. When symptoms are caught early, treatment can be extremely successful, returning the horse to normal health for many more years. While drugs treat the symptoms of Cushing’s syndrome, they do not treat the pituitary tumor itself. The tumour will continue to grow until it compromises the horse's quality of life. The simplest way to gauge improvement is to have the owner monitor the horse's water intake over a 24-hour period. This is best achieved by keeping the horse stabled and provided with water in a bucket. During this time other symptoms of Cushing’s syndrome, such as the heavy coat and pot belly, also disappear and the horse regains vigour and muscle tone.No treatment for Cushing’s will cure the disease. Therefore, the owner’s role will be to focus on careful health management and preventive treatment as follows: · Avoiding stressing the horse. The hormonal profile of many horses with Cushing’s already indicates high stress levels, so reducing stress is critical. · Providing a safe, comfortable “sanctuary” for the horse. · Sticking to a strict routine, this will help minimize stress. · Clipping the horse in warm weather; using blankets when it is cold. · Keeping up grooming to minimize skin diseases and keeping hooves in good shape. · Checking teeth regularly and having them checked by a professional twice a year. · De-worming regularly (usually every 30 – 45 days). · Providing an appropriate diet for the horse. This will usually involve elimination of simple carbohydrates.