Hypertension Can Trigger Sudden Blindness, yet Often Goes Unseen and Undetected

Many cat parents don’t realize that just like us, kitties can develop high blood pressure (hypertension). The primary difference between the two conditions is that in humans, the cause of hypertension is often unknown, whereas in cats, it’s usually the result of another disease or health condition.

High blood pressure typically doesn’t cause noticeable symptoms, which is why the first we learn of it in ourselves or our pets is during a physical exam at the doctor’s (or veterinarian’s) office. The lack of symptoms is also why hypertension has been dubbed the “silent killer” by the American Heart Association.1

Signs to Watch For

Cats, in particular senior and geriatric kitties, can develop very severe high blood pressure, which typically occurs secondary to either kidney disease or hyperthyroidism. If this is the case with your kitty, symptoms of those diseases will be what you notice and often include:

  • Loss of appetite
  • Vomiting
  • Increased thirst and urination
  • Weight loss
  • Dull coat

When you take your cat for a wellness exam, your veterinarian might notice a new heart murmur or alterations in the eyes, both of which should prompt a blood pressure reading. Your vet can take your cat’s blood pressure with a cuff placed on any leg or the tail.

The procedure is painless, and if your kitty is cooperative and not overly anxious, an accurate reading can be taken in just a few minutes. However, if your cat is stressed during veterinary visits (and many are), it can have a dramatic influence on his blood pressure.

If this is the case with your pet, it may be helpful to sit with him and soothe him until he’s more relaxed. Also consider administering a flower essence (e.g., a Solutions blend) or homeopathic Aconitum prior to your vet visit. These remedies can greatly reduce the likelihood of stress-induced increases in blood pressure readings. Several readings may need to be taken to obtain an accurate blood pressure.

If feline hypertension goes undiagnosed, the result can be significant damage to the eyes, kidneys, and/or the cardiovascular and nervous systems. If a cat’s high blood pressure isn’t addressed, the most common eventual symptom will be sudden blindness. Blood vessels in the eye burst, causing the retina to detach, and the kitty loses part or all of her eyesight.

This is one of the reasons I encourage regular veterinary visits, preferably twice a year, and especially if your pet is older. The sooner you know about your kitty’s high blood pressure, the sooner you can take action to prevent organ damage.

This Eye Exam May Help Detect Early Hypertension in Cats

Historically, there have been no early warning signs of high blood pressure in cats. But a 2014 study published in the New Zealand Veterinary Journal suggests routine fundic exams (eye exams that evaluate the back portion of the interior of the eyeball) in cats over the age of 8 can reveal ocular lesions associated with high blood pressure before symptoms appear.2

Since accurate blood pressure readings are notoriously difficult to take in stressed feline patients during veterinary visits, these screenings may prove especially valuable.

The New Zealand study involved 100 pet cats. Because unfamiliar environments are stressful for kitties, they were given time to acclimate to the clinic environment before the research began. All the kitties received thorough physical exams, and blood and urine samples were drawn to screen for chronic kidney disease, hyperthyroidism and diabetes.

The researchers took five blood pressure measurements for each cat, and only kitties for which consistent blood pressure measures could be obtained were included in study results.

Of 73 qualifying cats, 12 had hypertension-related ocular lesions as revealed during fundic examination, which included lesions on the retina, the choroid and the optic nerve. Ten of the 12 cats were also diagnosed with high blood pressure. Only three of the cats with ocular lesions showed symptoms of visual disturbance, and their lesions were more severe than those of the other nine kitties.

Six of the 12 cats with ocular lesions were also diagnosed with chronic kidney disease, which was the most common primary condition identified.

The 12 cats with hypertensive ocular lesions were given a standard drug used for systemic hypertension in kitties, and all showed improvement in ocular lesions in follow-up eye exams. The study authors concluded that:

“Ocular fundic examination of cats over 8 years of age allows identification of cats with hypertensive ocular lesions, often before the owner or veterinarian is aware the cat has a problem with its vision. This may result in diagnosis of systemic hypertension, allowing early treatment and resolutions of lesions.

The current study demonstrates that ocular lesions resulting from hypertension occur frequently enough in cats in Auckland to support the recommendation for fundic examination in cats over [8] years of age as part of the routine physical examination.”3

If your cat is middle-aged or older, and especially if he’s been diagnosed with kidney or thyroid disease, consider asking your integrative veterinarian about an ocular fundic examination.

Treatment of High Blood Pressure in Cats

If your kitty is diagnosed with hypertension, the first step is to identify and address any underlying disease. If no organ damage has occurred and your cat’s blood pressure isn’t dangerously high, regular monitoring of blood pressure readings while treating the underlying condition may be all that’s required initially.

If you must use hypertension medications, I recommend starting with a lower-than-recommended dose, as many cats respond well to sub-therapeutic doses. You can have these medications compounded into appropriate doses for felines. If your kitty isn’t showing any symptoms of high blood pressure, I recommend starting with nutraceuticals, homeopathics and herbs. Additional suggestions:

  • It’s important to feed a nutritionally balanced, species-appropriate diet, and if your kitty is overweight, you’ll need to help her get those extra pounds off by offering portion-controlled meals and daily aerobic exercise. Feeding a low-glycemic diet and avoiding carbohydrates will keep your cat insulin sensitive.
  • Make sure kitty is getting enough vitamin C and E. Studies indicate these vitamins can be helpful in lowering blood pressure. If you and your veterinarian decide a supplement makes sense, be sure to provide a natural (not synthetic) form of vitamin E. Natural vitamin E is always listed as the “d” form (d-alpha-tocopherol, d-beta-tocopherol, etc.) Synthetics are listed as “dl” forms and spelled “tocopheryl” (“yl” instead of “ol”).
  • Consider supplementing with olive leaf extract, which can cause a significant reduction in both blood pressure and LDL cholesterol. Talk with your integrative veterinarian about appropriate dosing for your cat.
  • Consuming omega-3 fats is one of the best ways to re-sensitize your cat’s insulin receptors and decrease blood pressure. Supplementing with a high-quality krill oil is a good source of omega-3 fatty acids.
  • Consider electroacupuncture, which has been shown to temporarily lower elevations in blood pressure in animals by as much as 50%.
  • Avoid unnecessary vaccinations.
  • Maintain consistency in your cat’s environment and routine. Kitties become highly stressed by changes in their external world, and a cat who is already dealing with health challenges needs a calm, consistent, enriched environment.

Laurelwood Animal Hospital,located near Jesuit High School on Beaverton-Hillsdale Highway offers a full range of companion animal services, including surgery, nutrition and behavior counseling, parasite control and preventative medicine. The hospital also offers advanced imaging through an all-digital spiral CT scanner, a comprehensive dental program and laser treatment.

If you’re looking for quality, compassionate veterinary care in Beaverton, Oregon, come visit us at Laurelwood Animal Hospital.

Laurelwood Animal Hospital

9315 SW Beaverton-Hillsdale Highway
Beaverton, Oregon 97005

Phone: (971) 244-4230
Fax: (503) 292-6808

E-mail: [email protected]