Hyperthyroidism is a common condition in older cats. In most cases it is caused by over activity of the thyroid glands, but in some cases is caused by tumours of these glands. It is normally quite easy to treat using long term medication, although there are other ways of treating it which may be necessary in some cases. The outlook is very good in uncomplicated cases but can be worse if there are other concurrent problems such as hypertension, heart disease or kidney disease.

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