This is Henry. Henry’s owner was worried as he went blind fairly rapidly, lost his confidence and sat around looking miserable. Examination showed that he had detachment of his retinas at the back of his eye. This can happen for lots of reasons in older cats but the commonest is because they have high blood pressure. Henry’s blood pressure was very high. Sometimes we can find a reason for the high blood pressure, kidney failure and an overactive thyroid gland (hyperthryroidism) are the two commonest causes, but sometimes there is no detectable cause (idiopathic hypertension). Henry has idiopathic hypertension and he is now on treatment and regular checks on his blood pressure. In many cases as we correct things, the retina will reattach and some sight at least be restored, it seems quite incredible when it works!
There aren’t any specific veterinary medicines to treat hypertension in cats so we have to use human ones, these often haven’t been properly tested on animals and their use is based on experience ‘in the field’. Whenever we use human medicines we are legally bound by something called ‘The Cascade’ which determines what we can use, the precautions we have to take and we have to get the owner to sign a consent form which specifies that the medicine hasn’t been trialled on pets, I’ll blog more about ‘The Cascade’, its history and practical use at a later date.