Causes of Hypertension in Cats
Hypertension in cats is most often seen in middle-aged to older cats.1 If left untreated, hypertension can damage organs such as the eyes, heart, brain, and kidneys. And since it can be difficult to detect because there are usually few, if any, outward signs, regular monitoring is key to picking up hypertension early.
Although there’s no obvious cause for hypertension in some cats, 8 out of 10 cats with hypertension have another disease that causes it.2
Those other diseases could be:
- Chronic kidney disease
- Hyperthyroidism
Chronic Kidney Disease
Up to three-quarters of cats with high blood pressure have chronic kidney disease.3 When the kidneys stop working so well, the body makes a few changes to try to get the kidney function back on track. This leads many cats with chronic kidney disease to develop high blood pressure.3
Hyperthyroidism
An overactive thyroid gland, or hyperthyroidism, is also common in cats with hypertension. Hyperthyroidism is common in older cats, even more so now than in the 1980s.4 The thyroid is a gland found in the neck that helps to control the body’s metabolic rate. When the thyroid becomes overactive, the cat’s metabolism increases, and that can result in high blood pressure.
Signs of Hypertension in Cats
Often there are no outwardly visible signs of hypertension in cats.
The most common signs of hypertension are:
- Blindness
- Behavioral changes
- Difficulty breathing
- Seizures
Blindness
Blindness in cats can happen because high blood pressure can damage the delicate retina at the back of the cat’s eyes and cause it to become detached. You may notice your cat bumping into things, and you may notice that your cat’s eyes look different because their pupils are dilated.
If you are concerned that your cat may not be able to see properly, you should visit your veterinarian without delay so that any further damage is minimized.
Behavioral changes
Bumping into things can indicate blindness, but other, more subtle, changes in behavior could also be a symptom that something is wrong. For example, if your cat’s appetite changes, if they become more vocal than normal, or if there is a change in their personality or energy levels, then you should get them checked.
Difficulty breathing
Cats can develop heart disease because of hypertension. The most common sign of heart disease in cats is shortness of breath or difficulty breathing.
Seizures
Because the brain is vulnerable to the damage caused by hypertension, some cats may seem depressed, wobbly, or even experience seizures.
If your cat has a seizure:
- Don’t move them or touch them unless they are at risk of injury.
- Make a note of how long the seizure lasts, what happens during the seizure, and if there are more than one, how often they occur.
- Contact your veterinarian for advice without delay.
Diagnosing Hypertension in Cats
The best way to diagnose hypertension in cats is an exam performed by your veterinarian.
Procedures may include:
- Blood pressure monitoring
- Blood and urine tests
Blood pressure monitoring
Regularly monitoring blood pressure is the key to picking up hypertension early. Measuring a cat’s blood pressure is easy, stress-free, and pain-free, so most cats tolerate it well.
Middle-aged and older cats should have their blood pressure measured at least once a year and more frequently in some cases.
The experience is very similar to going to the doctor and having the nurse take your blood pressure on your arm, except their tail or their foot is normally used. Because some cats are nervous away from home, it’s important to give them time to explore and relax before the measurement is taken. A small patch of fur may need to be shaved on their foot or the underside of their tail.
Blood and urine tests
Regularly monitoring (at least annually in middle-aged and older cats) blood and urine is also important.
Routine blood tests are useful for identifying kidney disease because waste products build up in the blood when the kidneys aren’t working well. The concentration of urine also changes when the kidneys are diseased.
If your veterinarian suspects hyperthyroidism, then they will also check the thyroid hormone levels in the blood.
Managing Hypertension in Cats
Hypertension in cats is easily managed with daily medication, just as it is in people. Once established on their medicine, your vet will continue to check your cat’s blood pressure to make sure the medicine is working and that the dose doesn’t need adjustment.
And of course, since most cats with hypertension have an underlying disease (such as chronic kidney disease or hyperthyroidism), your veterinarian may also suggest additional medicines or management to help control the underlying disease. Therefore, there’s a lot that you can do to help your cat live a long and happy life.
Key Takeaways
Hypertension is common in middle-aged to older cats.
Most cats have hypertension because of chronic kidney disease or hyperthyroidism.
Hypertension damages organs such as the eyes, brain, heart, and kidneys.
Hypertension in cats is often a silent disease, with no outward signs for a long time.
Regularly monitoring blood pressure, blood, and urine is key to identifying hypertension and the diseases that cause it early.
Hypertension can be easily managed with an anti-hypertensive medicine.
