By Dr. Becker
If you're owned by a cat, you may not realize it, but your pet can develop severe high blood pressure, also called hypertension. The condition is most commonly seen in senior and geriatric cats.
High blood pressure in felines is a serious disease that usually occurs secondary to another illness like kidney failure or hyperthyroidism. In fact, over 60 percent of cats with renal failure and 90 percent of hyperthyroid kitties are also hypertensive.
Left untreated, high blood pressure can result in significant damage to four major organ systems: the kidneys, the eyes, the nervous system and the cardiovascular system. If a cat's high blood pressure goes unchecked, the most common eventual symptom will be sudden, acute blindness. Blood vessels in the eye will burst, causing the retina to detach, and the kitty will lose part or all of her eyesight.
Historically, there have been no early warning signs of high blood pressure in kitties. But a study published recently in the New Zealand Veterinary Journal1 suggests routine fundic exams (eye exams performed to 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. And since accurate blood pressure readings are often difficult to take in feline patients, these screenings may prove especially valuable.
Study Reveals Presence of Ocular Lesions in Hypertensive Cats
The study was conducted at Massey University in Auckland and involved 100 pet cats. Because unfamiliar environments are stressful for kitties, the study subjects were given time to acclimate to the clinic environment before the study began.
All the cats were given complete 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 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.
"Ocular lesions resulting from hypertension occur frequently enough in cats... to support the recommendation for fundic examination in cats over 8 years of age as part of the routine physical examination."
Dr. Becker's patient, Tarzan, who has congenital hypertension
Treatment of Hypertension in Cats
If your kitty is diagnosed with high blood pressure, the first step is to identify and address any underlying disease like renal failure or hyperthyroidism.
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 is 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 them compounded at a pet pharmacy that makes human drugs into appropriate doses for felines. But if your pet isn't showing any symptoms of high blood pressure, I recommend starting with nutraceuticals, homeopathics and herbs.
- It's important to feed a 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 exercise sessions. Feeding a low-glycemic diet and avoiding carbohydrates will keep your cat insulin sensitive.
- Make sure your kitty is getting enough vitamin C and E. Studies indicate these vitamins can be helpful in lowering blood pressure. If you and your holistic vet decide your kitty needs a supplement, make 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.) Synthetic vitamin E is listed as 'dl-' forms and spelled tocopheryl, with a '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 holistic vet 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 electrical acupuncture, which has been shown to temporarily lower elevations in blood pressure in animals by as much as 50 percent.
- 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.