How do I know if my cat has high blood pressure?

This is Kitty - why is she falling?

Does this cat look like she has high blood pressure? It's hard to tell from the outside, so routine testing, or "screening" is usually the best way to tell.

Most of the time, when we diagnose cats with high blood pressure, their owner has no specific complaints about their cat's health or behavior. That is because most of the negative effects of high blood pressure in cats are subtle, and act internally before outward signs are seen.

One of the most common causes of sudden blindness in cats is high blood pressure. This is because the tiny blood vessels are put under a lot of strain when a cat has chronic high pressure. This can cause the vessels to rupture or break and small areas of the retina lose blood supply. Once the blood supply is gone, small lesions or detachments form, giving your cat spotty vision. If this goes on for long enough, the entire retina can detach and cause complete blindness.

Fortunately, if high blood pressure is caught early, before too much retinal damage has been done, the lesions can heal, with treatment.

This particular cat was brought in to have an exam because she was wobbly and had started falling off a chest of drawers where she liked to sleep. The only thing that was found on her exam was that she had high blood pressure and some changes to the retina:

So, that's one problem on her list - but is her high blood pressure making her fall?

Sometimes, when a cat has high blood pressure, it is due to the presence of another disease, such as kidney disease, or hyperthyroid disease. In fact, 61% percent of cats with chronic renal failure and 87% of cats with hyperthyroidism have high blood pressure, according to research (citation below).

For Kitty, we took a blood sample to test for kidney disease and hyperthyroid disease. We discovered that Kitty did have some mild changes to her kidneys, too. We started blood pressure medication for Kitty, and when she came in to have her pressure rechecked, her owner told us that she was a changed cat! She had significantly improved, and was no longer wobbly or falling off her favorite sleeping spot.

High blood pressure can cause signs that owners can note, but again, most people only recognize that there was a problem after their cat's high blood pressure is being treated. We hear comments like: "Fluffy is so much less cranky!" or "Callie's appetite is so much better!" or "Smokey seems so much less restless and has stopped crying at night!" when people come in for their blood pressure rechecks.

Other symptoms of high blood pressure (besides blindness and retinal detatchment) include:

• Seizures
• Circling/disorientation
• Dilated pupils
• Hemmorrhage (bleeding) of the eye or nose
• Blood and/or protein in the urine
• Abnormal kidneys
• Heart murmur
• Weakness
• Signs of thyroid disease

If you think your cat may have high blood pressure, or if your cat is over the age of 7 years and you would like your cat screened for high blood pressure, you may want to consider participating in a current high blood pressure study that is being run. For more information about the study, visit www.mycatcanhelp.com or read more about it on our blog at "Feline Hypertension: What you need to know!"

J Vet Intern Med. 1990 Mar-Apr;4(2):58-62. Hypertension in cats with chronic renal failure or hyperthyroidism.

Kobayashi DL¹, Peterson ME, Graves TK, Lesser M, Nichols CE.

Feline Hypertension: What you need to know

High blood pressure? In a cat? All your cat does is lie around all day, grooming himself and sleeping - he couldn't possibly have high blood pressure, right?

Wrong!
In humans, we think about high blood pressure as a problem of high-stress, high-anxiety people with high-pressure jobs. According to the American Heart Association, however, science has not definitively proven that stress causes high blood pressure, even in humans. It is more likely that people under stress will engage in unhealthy activities that ARE linked to high blood pressure - such as smoking, drinking too much alcohol, and eating an unhealthy diet or not exercising regularly.

Unlike human high blood pressure, feline hypertension is not usually a stand-alone disease. It is most often seen associated with another illness, such as kidney disease or hyperthyroidism. However, in cats that have kidney disease, it is often uncertain whether the kidney disease caused the hypertension or chronic hypertension damaged the kidneys.

Symptoms: Just as in humans, there are few, if any, outward signs of high blood pressure in cats.

The "bubbles" in this photo of the inside of a cat's eye indicate areas where the retina is detached due to chronic high blood pressure

The most common sign of high blood pressure, and the one most recognizable by owners, is sudden blindness. Blood vessels under high stress in the eye are at high risk for rupture or leakage, which damages the retina. Over time, this can lead to complete retinal detachment and complete blindness.

Some cats with high blood pressure will develop a heart murmur or a "gallop" rhythm due to damage to the heart - most commonly a thickening or overgrowth of the muscle of the left ventricle.

Sometimes people who start treating their cats for their high blood pressure notice a change in their cat's behavior (for the better!), noting that they seem less anxious, or they have stopped howling at night, or they appear more active.

It is known that in humans, high blood pressure can cause headaches. This is very difficult to diagnose in cats, however, we know that cats experience pain in a similar manner to humans, so one might wonder if cats with high blood pressure also experience headaches.  If so, diagnosing and treating high blood pressure would relieve your cat of head pain.

Other outward signs and symptoms that may appear with high blood pressure are associated with the primary disease that is linked to the hypertension: increase in water intake and urine output, dull coat, weight loss, change in appetite (either eating more or eating less), vomiting, diarrhea, constipation, and behavior or personality changes.

Inwardly, chronic high blood pressure can lead to organ damage.
65-100% of hypertensive cats have decreased kidney function
50-70% of hypertensive cats have damage to their hearts
30-40% of hypertensive cats have damage to their retinas which can ultimately lead to blindness if left untreated
15% of cats with high blood pressure have neurologic signs including head-pressing, twitching or seizures

Prevalence and Risk Factors: The cats that are at highest risk for high blood pressure are senior cats, especially those over the age of 10 or those with other health conditions. There does not seem to be a specific breed that is at high risk for high blood pressure. 

High blood pressure in older cats appears to be fairly common, especially as a secondary problem associated with other diseases. Exactly how common is still up for debate. In researching for this article, many studies disagreed about the numbers, and most of the studies were performed with 100 or fewer cats - but we do know that hypertension is a serious issue that we can easily diagnose and treat.

Somewhere between 20-65% of cats with chronic kidney disease have hypertension.
Somewhere between 9-23% of cats with hyperthyroid disease have hypertension.

Somewhere between 17-50% of cats with high blood pressure have hypertension that is not associated with another problem.

Diagnosis: High blood pressure in cats is diagnosed with a blood pressure reading, very similar to the readings taken in humans. While oscillometric (electronic, automatic) blood pressure machines exist and are quite accurate in humans and dogs, the Doppler method of blood pressure examination is generally recommended as the most accurate in cats. The oscillometric units are often unable to detect feline blood pressure (in up to 52% of cases!), take longer to get a result, were less precise and often read lower than the actual pressure.

Checking a blood pressure with the Doppler method is painless and most cats are quite calm and unconcerned by the process. After the cat has time to acclimate itself to the exam room, the technician attaches a small cuff (the same kind that is used in human neonatal medicine) to one of the cat's legs. Preferably, the cat's owner is present to calm and hold the cat for the technician, but occasionally, just like small children, a cat may behave better for a group of strangers than in front of his or her "parents", or they may feed off an owner's anxiety and become anxious, themselves.

A small amount of alcohol is applied to the cat's foot or a small amount of hair is shaved near the paw pad, and then ultrasound gel is applied to the Doppler probe and is it gently pressed against the cat's foot. The Doppler machine is turned on, and the heartbeat becomes audible  as a "whoosh whoosh" noise. Every effort is made to keep the cat calm and relaxed during this process, to avoid artificially raising the blood pressure. Several readings are taken and the average of these readings is recorded.

Doppler blood pressure machine and supplies

 

The cat either reclines on its side for a rear leg pressure check or sits/lies in a normal position for a front leg reading. In some cats, it may be appropriate to take a measurement from the tail.

The blood pressure cuff is wrapped around the leg, and some alcohol is used to wet the fur. In some cases, a small amount of fur is shaved near the cat's paw pad. Ultrasound gel is applied to the Doppler probe and then held gently against the foot. The blood pressure cuff is then inflated and several readings are taken.

Treatment:

Amlodipine is usually the medication veterinarians turn to for treatment of high blood pressure in cats. This medication relaxes the blood vessels to allow the blood to pass more easily. Most cats started on this medication are started on a low dose and then re-checked in a couple weeks to ensure that they do not need to have additional medication. This avoids adverse side effects from a sudden decrease in blood pressure such as weakness or fainting spells, but also allows for appropriate correction of blood pressure that is severely elevated within a short period of time. Other medications such as benazepril and atenolol may be preferable in some cases, depending on the cat's overall health.

Additionally, treating any primary disease such as hyperthyroidism, diabetes, kidney disease, may aid the control of high blood pressure.

Currently, Exclusively Cats Veterinary Hospital is participating in a nationwide study of an FDA-regulated investigational medication for high blood pressure associated with chronic kidney disease in cats. This clinical trial is designed to determine the effectiveness of the investigational medication in a real-world situation. We hope you will consider this opportunity to possibly help your cat and, potentially, many other cats nationwide. 

ANY CAT* over the age of 7 is currently eligible for a free exam and blood pressure screening. 

For more information, call our office at 248-666-5287 or visit www.mycatcanhelp.com.
To get involved, please call our office to schedule an appointment!


*Any cat that is not currently on blood pressure medication, and is not an F1 generation Savannah Cat or Bengal breed.


Selected Resources and References:
More information:
High Blood Pressure in Cats: Winn Feline Foundation
High Blood Pressure (Hypertension) in cats: FAB cats
Diagnosing Feline Hypertension: Pet MD
All About Hypertension: Tanya's Comprehensive Guide to Feline Chronic Kidney Disease
Hey, Doc, Why Did My Cat Go Blind? by Dr. Eliza Sundahl at Felinedocs.com

Research and Journal Articles:
Management of Hypertension in a geriatric cat: Canadian Veterinary Journal
Managing Hypertension in Cats with Hyperthyroidism: Proceeding of the SEVC

Southern European Veterinary Conference Oct. 2-4, 2009, Barcelona, Spain, Thomas K. Graves, DVM, PhD, DACVIM 

Prevalence of systolic hypertension in cats with chronic renal failure at initial evaluation. J Am Vet Med Assoc. 2002 Jun 15;220(12):1799-804. Syme et. al

Blood Pressure in Small Animals - Part 2*:Hypertension - Target organ damage,

Heart and Kidney, A.P. Carr, B. Egner

Feline Systemic Hypertension: Classification and pathogenesis, E Rosanne Jepson, BVSc (Dist) PhD MRCVS∗
Feline Systemic Hypertension: Diagnosis and Management, Rebecca L Stepien, BS DVM MS DipACVIM (Cardiology)⇓

Evaluation of Doppler Ultrasonic and Oscillometric Methods of Indirect Blood Pressure Measurement in Cats. Haberman et al. 2004.

 A comparison of CAT Doppler and oscillometric Memoprint machines for non-invasive blood pressure measurement in conscious cats. Jepson et al. 2005.
  The Prevalence of Ocular Lesions Associated with Hypertension in a Population of Geriatric Cats in Auckland, New Zealand. Carter et. al, 2013
Routine health screening: findings in apparently healthy middle-aged and old cats. Paepe et. al. 2013
Systemic Hypertension in Cats: Current Issues in Diagnosis and Therapy, AAFP 2011 Conference 9/9-9/11. Daniel F. Hogan DVM, DACVIM (Cardiology)

Feline Veterinary Clinical Trial Announcement: Help cats and earn free veterinary care!

Any patient over the age of 7 is currently eligible for a free exam and blood pressure screening.

A cat having retinal photos taken

If your cat has high blood pressure, he can progress to the next phase of the study and receive free study-related bloodwork, urinalysis and retinal photographs evaluation by a board-certified Veterinary Ophthalmologist.

If your cat's exam results qualify him for the next part of the study, ALL visits, medications, and additional diagnostics associated with the study will be covered. Additionally, you can earn up to $400 towards future veterinary care, if your cat completes various stages of the study.

This study is "double-blinded", which means that your cat may receive a placebo (inactive medication), however, he is twice as likely to receive the study medication as the placebo. The first part of the study lasts 28 days and, if your cat is being treated with the study medication, you may choose to continue to the second part of the study which lasts for up to 5 additional months.

For more information, call our office at 248-666-5287 or visit www.mycatcanhelp.com.
To get involved, please call our office to schedule an appointment!

Meet Mr. July!

Oliver Simon Trouble-Maker Light

Age: Almost 2

Weight: 12.70 pounds, good body condition

Birthday: July 12, 2010

Gender: Neutered Alpha-Male

Demeanor at the veterinary office: Sweet kitten, but vocal and wiggly!

Feline Friends: Basil and Kitty

How I found my furr-ever home, by Oliver's mom: 

I have had trouble finding and keeping healthy cats my whole life. When I was just a little girl I decided to name my very first cat Princess Sparkle Rainbow Cookie Unicorn Mermaid. As you can imagine this name was difficult to remember and just plain stupid so my parents simply named her Kitty. Kitty-One, as we now call her, was a black and white fluff ball of amazingness and I loved her dearly. My favorite activities included carrying her around and dumping bags of treats on the floor for her to devour. I can imagine she wanted to escape from me - I was too young to know that cats didn’t like to be pulled by their tails and what direction they wanted their fur petted, so she escaped out the front door one day and she never came back.

My parents and I felt the void of a cat-less home and searched for another adorable kitten to replace the one that we had lost when we came across an adorable orange and white kitten with the biggest green eyes I had ever seen and his tiny black calico sister at our local PetSmart. I let my younger sister have the adorable calico whom she named Princess Stormy and I fell in love with my adorable orange cat whom I named, Kitty Happy-Cat Light. These two kittens loved each other, always cuddling and keeping each other safe and comfortable. However it wasn’t meant to last and Kitty’s sister, Stormy, suffered from kidney disease at a young age and had to be put to sleep. 

Some time later, my sister adopted two kittens from Ohio, Batman and Casper, who turned out to have Feline Leukemia. We obviously couldn’t keep them for the risk of Kitty catching this highly contagious disease so we brought them to Leuk’s Landing where they enjoyed the rest of their very short lives.

Although a very, very happy cat, Kitty seemed to feel the loss of his sister and I felt that he needed a feline companion to keep him young and active. I looked for a tiny companion for Kitty every time I went shopping for cat-litter and food until one day I found Oliver Simon Trouble-Maker Light. When he looked up at me with his tiny yellow-green eyes my heart melted and I knew I was going to take him home. You see, I have a weakness for orange cats. I could feel his energy through the little glass enclosure and I knew I had to bring him home. I also picked out a buddy for him to play with, Basil Fat-Fatty Moe Light. Oliver was adopted with his tiny buddy, Basil, from PetSmart on Orchard Lake Road in 2010.

Description of Oliver:

Oliver is the absolute softest cat you will ever feel. His bunny fur is light orange and striped (Our house-keeper calls him the yellow-cat) with an adorable white chin that looks as if he just gulped down a whole bowl of milk. He has replaced Kitty as the Alpha-Male in our household, continuously play-battling Basil for the rights to the throne. He allows Kitty to rule the household, always knowing that he could take command at any moment. Kitty and Oliver seem to have a special bond because they are often spotted having top-secret conversations with each other. 

My friends and I like to think of Oliver as a lion! Oliver’s walk is slow and powerful but he can run at lightening fast speeds. He relaxes in positions of virility and yet is always full of energy, ready to pounce at any moment. Don’t be too intimidated though because Oliver makes the cutest high pitched “prrrr-ow” noise, no fearsome-roar from him! He likes to lay on his back in the center of a room with his hands and feet curled around each other and his big fluffy tail wrapped around his feet. If you don’t pay enough attention to him, even while he is pretending to sleep he will open one eye, “purr-ow” and then close them really quickly so you remember to find out how cute he is being. If you ever can’t find Oliver, it’s because he is sleeping on my bed, which seems to be the communal cat rest-area. On the rare occasion that I allow Oliver to go outside, he mows down the grass in our lawn with his razor sharp teeth and tries to chase butterflies.