The Family Pet by Dr. Michael Trapani - Too Much Pressure - July 2018
Today’s high stress feline executive lives under a great deal of pressure. Making mission-critical decisions, such as deciding on the most advantageous window seat for napping, and management of distracted, unfocused humans takes a toll on even the most laid back kitty VIP. Between the lack of vacation time (When is the last time YOUR cat got a day off?) and the unceasing calls for attention from ever-needy human house mates, it’s a wonder our poor little kitty darlings survive at all. Some cats turn to tuna in a vain effort to manage the strain, but most of them simply suffer in silence. Is it any surprise that so many of our cats suffer from hypertension?
And that’s where this little fantasy fall off the rails: Cats really DO suffer from hypertension. And some of it IS stress. Changes in the home situation, introduction of other cats to the household or (gawd forbid) a new puppy, can amp up the stress level of even the most staid kitty. But Feline Hypertension is a THING, and has some very bad effects on the health of cats.
What is it? Blood pressure is measured in millimeters of mercury (mmHg). The human standard is 120/80 mmHg, with the systolic (as the heart beats) number on top and the diastolic (between beats) on the bottom. Because of their small peripheral arteries, it can be extremely difficult to measure a cat’s diastolic pressure, so we usually talk about the systolic pressure only. Cats run a little higher than humans, and aren’t considered hypertensive until their systolic pressure exceeds 160 mmHg. Hypertensive cats turn up with blood pressures exceeding 220 mmHg fairly often!
Kitty blood pressure is measured exactly as it is in humans, with a pressure cuff and sphygmomanometer: The doctor listens to the sound of blood flowing through an artery with a stethoscope as the cuff pressure is increased, and measures pressure as the sounds change. Cat arteries are so tiny that a Doppler ultrasound sensor is required to hear those sounds, which means the cat must be clipped, smeared with ultrasound gel, and restrained for several measurements in order to obtain the blood pressure reading. This procedure can be stressful and time consuming.
In our facility, we use oscillometric measurement. The blood pressure monitor uses a special cuff that inflates while a computer makes repeated measurements and calculates the blood pressure from changes in limb size with each pulse. No clipping is required and much less restraint is needed to obtain the measurement. Most cats accept the cuff and sit happily through the procedure, so it’s possible to get accurate blood pressure measurements right in the exam room.
It’s important to check a cat’s blood pressure because hypertension promotes a number of severe problems. One common result of hypertension is sudden blindness resulting when arteries in the retina burst and bleed, causing detachment of the retina or sometimes the development of huge blood clots within the eye. Hemorrhages can occur in other tissues as well, including the kidneys and brain, sometimes with disastrous consequences. In-creased cardiac workload from hypertension can damage the heart, causing hypertrophic cardiomyopathy. Hypertension results in over-pressure of kidney filtration units, resulting in kidney degeneration leading to renal failure. Cats with high blood pressure may vomit, become lethargic, lose weight, and show poor coat quality, drink excessive amounts of water, urinate more frequently, or have catastrophic signs such as hypertensive brain inflammation and sudden death. Most are just “ADR” kitties: Ain’t Doin’ Right.
How many cats suffer from high blood pressure? Quite a few. As in people, the problem is more common in those with certain predisposing factors and age-related diseases. Hypertension is found in up to 75% of cats with degenerative kidney disease, a common problem in older kitties. In these patients, age-related kidney degeneration triggers a re-flex that raises blood pressure and accelerates kidney failure. Hyperthyroidism, another common problem, results in hypertension in about 25% of all affected cats. Hypertension both causes and results from some forms of feline cardiac disease, making a bad situation worse. Hypertension is common in cats who are obese, have diabetes, and, of course, kitty pack-a-day smokers.
Treatment of feline hypertension is relatively straightforward. Our first priority is management of predisposing diseases. Then, if hypertension persists, simple, inexpensive medications given once daily will usually control the problem. The biggest challenge with feline hypertension is recognizing the disease. Ask your veterinarian about blood pressure testing for your cat today.
