Does your cat have high blood pressure?
Don’t laugh – high blood pressure or hypertension is a very common condition in older cats.
Do you have any idea how much our feline friends here stress out about uncontrolled growth, big boxes and affordable housing? All kidding aside, it’s not too hard to see why when you realize hypertension is associated with the following feline diseases: hyperthyroidism, chronic renal disease, diabetes mellitus, heart disease and endocrine disorders. The “cool cat” image is up for review in many of our worried cats.
In one study, 60 percent of cats with kidney failure and a whopping 80 percent of cats with hyperthyroidism had high blood pressure. Many, if not all cats with hypertension, have detached retinas or bleeding in the eye. Obviously, routine eye exams in older cats can be very helpful as a screening test for hypertension.
Another very consistent finding in cats with high blood pressure is cardiomegally – an enlarged heart. The heart is a muscle and if it has to work harder by trying to pump blood through “tight” arteries it will respond by growing larger.
These findings are important because checking blood pressure in cats is really an inexact science. Blood pressure readings in cats are quite variable and are greatly affected by stress. Do you know of many kitties who are not stressed out when in a veterinarian’s office?
We can only rely on multiple readings taken in a stress free environment as reliable. However, blood pressure readings only become important when we are trying to monitor response to treatment.
This is because of our excellent researchers. They have told us with certainty that if a cat is suffering from one of the above mentioned diseases – especially renal and thyroid disorders – they are most likely hypertensive.
If your cat is older you should be getting a geriatric workup at least every year. A geriatric exam includes doing a physical exam – including eye exams – and some laboratory testing. A complete blood cell count, blood chemistries, thyroid blood tests, urinalysis, EKG and chest radiographs are also recommended for older cats. It really depends on how old your cat is before the entire battery of tests are run; run them all if your cat is nine or older.
Treatment of hypertension in cats is similar to treatment in humans –repeat after me “low sodium diet.”
Most diets used for kidney or heart disease in cats are low sodium; examples are Hill’s K/D and H/D, and Purina’s NF Formula. It is best to make these changes slowly over a one-to-two-week period as it takes diseased kidneys a little longer to adjust to changes in sodium. Unfortunately, many cases of hypertension due to renal failure do not respond well to salt restriction, but it is still recommended. In fact, hypertension secondary to renal disease doesn’t respond much to drug therapy either.
Getting to the underlying cause of hypertension is really how to treat it. First, control the underlying disease. Drug therapy may include diuretics (lasix), beta-blockers (propanolol), ACE inhibitors (captopril or enalapril), calcium channel blockers (cardizem) and vasodilators (nitroglycerin or hydralazine).
Treatment of thyroid disease entails either medication, surgery or radiation.
As you can see by the number of conditions that cause high blood pressure in cats, it is really quite common. The treatments can require close monitoring of your kitty by your veterinarian and I’d recommend getting to know them on a first name basis.
Dr. Stephen Sheldon, owner of Valley Veterinary Services, practices by appointment at Alpine Meadows Veterinary Hospital in Edwards. He can be reached at 748-3062.