Middle aged to older cats can suffer from high blood pressure (hypertension). It occurs when a cat’s arterial blood pressure is continually higher than normal. This can be the result of worsening renal function or hyperthyroidism (elevation in thyroid hormone) but mostly we just don’t know why it happens.
High blood pressure can affect many organs in a cat’s body, but one of the common symptoms we see is blindness. It can occur suddenly, and the cat’s owners may notice strange behaviour, such as bumping into furniture, missing a door to go through or a chair to jump on. Recently a customer of ours noticed a minimal response from her cat when approaching one of the cat’s eyes with her hand. When presented at the clinic it was soon obvious that the eye was blind due to high blood pressure. Treatment was started immediately and the other eye was saved.
Blood pressure is measured in the same manner as with humans – an inflatable cuff is placed on a paw, or more conveniently on the tail, while the cat sits quietly in her cage.
Allowing the patient to settle down and get comfortable after a trip to the vet will assure a true reading, not just false elevation due to stress. For that reason, we like to keep them in for a few hours. Sedatives are not needed, just a quiet calm environment and minimal handling. We normally take several readings throughout the stay.
A small tablet (amlodipine) taken daily controls the pressure and prevents any further damage to the eyes, kidneys or other organs.
Cats are very good at hiding their poor eye sight. By using their whiskers, sense of smell and by following their common routine, they can get around without their owners noticing any problems. A subtle change of behaviour can be significant though, so please get in touch if you feel your cats vision may be compromised.