Published on August 23, 2016
Hypertension, or high blood pressure, is common in older cats. Just as in people, most cats have no obvious signs of disease until there is an acute — usually serious — incident. Due to a very strong public health campaign, most people are now aware of the dangers of chronic hypertension; it is rare to make a visit to the doctor for any reason and not spend a few moments in a blood pressure cuff. A wise recommendation would be to perform routine blood pressure checks in our older feline friends as well.
Dangers of Hypertension
A hypertensive cat is at constant risk for brain, kidney, heart and eye damage. Long term hypertension will increase the everyday work load on the heart, predisposing to thickening of the heart muscle and eventual heart failure. Ongoing vascular changes injure the kidneys and brain. Often an abrupt event brings the patient to a veterinarian. Acute blindness from retinal detachment is common. The sudden onset of confusion, seizures or balance issues can signal a stroke-like injury to the brain. Emergency intervention can sometimes bring down the pressure. Given time, these cats may return to “normal,” but the progressive damage already caused by chronic hypertension cannot be reversed.
Some cats have subtle signs of hypertension that may be noticed at home by an astute owner. Some patients will “yowl” as if lost or show other signs of mild dementia. These cats may be brought to the veterinarian specifically for this behavior. Most high blood pressure in cats, however, if not diagnosed on emergency, is discovered as part of a routine senior cat examination.
Hypertension in cats can be a primary problem, but usually it is secondary to other diseases. It most commonly accompanies chronic kidney disease and hyperthyroidism, both common disorders of the middle-aged to older cat. Your older cat’s annual exam ideally includes bloodwork, urinalysis and a blood pressure check. In addition to detecting disease, establishing what is a normal for your healthy pet provides very useful information if he or she has a veterinary emergency.
How Do We Take a Cat’s Blood Pressure
The measurement of feline blood pressure is similar to measurement in people. A small cuff placed around a paw or the base of the tail is inflated until it blocks blood flow through the underlying vessel. The cuff is then slowly deflated until the technician is able to hear the return of blood flow. The cuff pressure at this point equals the cat’s systolic pressure. Veterinarians primarily use the systolic pressure to assess hypertension.
What is Normal
While blood pressure values considered “normal” account for the stress your cat may experience at the veterinary office, it is helpful to give a feline patient a few moments to adjust to being out of the carrier in the exam room before taking any measurements. Less than 160 mmHg is considered a normal pressure. 160-180 mmHg is borderline hypertensive and may require treatment or at least rechecking. Greater than 180 mmHg is clearly hypertensive, and greater than 200 mmHg is dangerous and requires immediate attention.
High blood pressure in cats can usually be managed successfully with oral medication. Veterinarians often begin treatment with once daily dosing of Amlodipine, a medication that dilates arteries. Occasionally, cats may require twice daily dosing or addition of another type of vasodilator. These medicines have very few bad side effects, although initial loss of appetite or low blood pressure are possible.
Routine Check-Ups are the Best Defense
As in people, the best treatment for the danger of hypertension in your feline friend comes from early detection. By collecting baseline bloodwork, urinalyses and blood pressures periodically as your cat ages, you can detect problems and trends early on. When facing this silent menace, prevention is always the best medicine.