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.

Case study: Sally - Progressive Retinal Atrophy (PRA) in cats

Sally

 Sally is a 3-year-old Abyssinian cat that was rescued from a hoarding situation. She was one of 84 cats rescued. Eighty of the cats in the household were too ill or debilitated to survive and had to be euthanized. After adoption, it was discovered that Sally was Feline Leukemia positive. She is shy, but sweet, and her owners brought her in to us because she suddenly appeared to lose her sight. She began bumping into things and lost her fear of the dog. If you notice in her photo, her pupils are very dilated, and her owners had noticed this at home, too. Her regular veterinarian sent her to us because high blood pressure was suspected.

What does high blood pressure have to do with eyesight?

The retina lines the back of the eye

The retina is a thin membrane lining the inside of the eye that receives light and translates it into electrical impulses for the brain with special cells called photoreceptors. There are two kinds of photoreceptors - rods that process black and white or dim light vision and cones that process colors or bright light. If the retina or its photoreceptor cells become damaged in some way, the eye has trouble converting waves of light into signals that the brain can understand, interfering with a cat's vision.

 One of the ways that cats can lose their vision is by developing hypertension lesions in the retinas - tiny blood vessels are damaged and regions of the retina lose their ability to function as they lose their blood supply. These lesions look like bubbles in the retina. If a cat's blood pressure remains elevated for a long period of time, the retina can completely detach and lose its connection with the nerves that transmit visual impulses to the brain. Once this has happened, a cat becomes irreparably blind. If the hypertension is diagnosed and treated early, as in these photos, the retinal lesions can heal over time.

Retinal lesions appear like bubbles in the back of the eye

The same eye 2 months after starting blood pressure medication

 Notice that not only are the lesions gone, but the blood vessels appear more visible.

The first thing that we did when Sally came in was check a blood pressure reading. Her blood pressure was 150mmHg, which is a normal pressure in a nervous cat. Hypertension was not the culprit in this case. So, what could be the problem?

The next thing that happened was that Sally received a full physical exam from Dr. Demos, including an eye exam. This is what Dr. Demos saw when she looked in Sally's eyes...

Something very important is missing, here!

There are no blood vessels in this retina!
This is a characteristic feature of something called Progressive Retinal Atrophy (PRA). PRA is a recessive trait in certain breeds of cats such as the Abyssinian, the Somali and the Ocicat. Perisans and Siamese are also often at risk. There are a number of other breeds that have also been identified to carry the mutated gene in small numbers.

Other key features of this disease are a granular appearance to the retina, signs of retinal thinning, and a reduction or thinning of blood vessels. Increased reflectivity of the retina and dilation of the pupils are symptoms that owners can easily see at home. Later stages show pigment changes to the retina and a degradation of the optic nerve. These changes usually happen equally to both eyes at the same time.

Sally's pupils stay dilated, even in bright light

The most common form of PRA in cats is involved a progressive degeneration of the rod and cone receptors in the retina.The cat's eyes develop normally as a kitten, but as the cat gets older, the cat will begin to experience night-blindness and may tend to avoid stairs or darkened areas of the home. It will progress to total blindness by the age of 3-5 years. This is problematic not only for the cats themselves, but for the breeders of high-risk breeds, because often the disease is not apparent until after the age at which many cats have already participated in a breeding program. If you are interested in a purebred cat, it may be a good idea to ask your breeder about PRA and whether their cats have been genetically tested for the mutation.

Unfortunately, this is a problem for which there is no treatment. However, the good news is that cats adapt well to being without their sight due to their superior hearing, sense of smell and sense of touch (whiskers). You can read about the amazing cat, Homer, who caught flies out of the air without the aid of sight!

If your cat starts to show reluctance to move around at night, or has trouble jumping onto furniture, or starts to bump into things, it would be a good idea to have your cat's eyes checked by his or her veterinarian, as well as having a blood pressure exam performed.

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!

Does An Apple a Day Keep the Veterinarian Away? - Feline Health Myths, Part 5

Myth: Cats lose weight because they are old.

Unhealthy weight loss is often accompanied with a change in hair coat.

Reality: This is a great myth to talk about right now, since September is Senior Cat Month!  It is generally true that older cats will lose weight, but old age is not a cause of weight loss. Cats don’t diet, so your obese cat is not likely losing weight because he didn’t like his silhouette in the mirror. If you look more closely at these older cats that are losing weight, some may be eating normally, some may be eating less, and some may be ravenous! 

The older cat that is eating normally or less than usual: Is your cat drinking more water than usual? Are you noticing larger clumps of urine in your litterboxes when you scoop? Your cat may be showing signs of kidney disease.

Is he no longer jumping up on the counters like he used to? Do stairs seem to intimidate him? If so, then your cat may be suffering from arthritis, or may be experiencing some changes to his vision. His food may be in an area where he can no longer easily access it.

Does he drool? Or does his breath smell bad? Many cats seem to ignore extremely painful dental disease, but others will decide not to eat as much food if their teeth are painful.

Are there no other signs besides weight loss? Or maybe your cat’s stools are less than ideal – runny or malodorous? It is possible that your cat has chronic inflammation in the intestinal tract, or lymphoma, which is a cancer that attacks the intestinal tract.

The older cat that is ravenous and/or vomiting: If your cat is vomiting more than usual or ravenously hungry, it can be a sign of hyperthyroidism. The thyroid gland is located in the neck region and can become overactive as cats age. The gland may grow in size, too, and can sometimes be felt by running a finger over the underside of the neck. This has effects on the metabolism, heart rate and energy level of a cat, generally speeding things up. This gives them less time to digest their food, which can cause runny stools. The changes to the heart can cause high blood pressure and can cause damage to the heart muscle itself. A high energy level may make your cat seem kittenish again, but may also cause him to keep you up at night with inappropriate yowling or high activity levels. Thyroid problems can also cause increased thirst and urination which can mask kidney damage. Fortunately, hyperthyroidism is very treatable – but the sooner it is treated, the less lasting damage is done to the body.

Another reason your cat may be ravenous or eating normally but losing weight may be diabetes. Often diabetic cats will drink more and urinate more than normal. They eat a lot because their bodies cannot use the sugar (glucose) that is in their food to make energy. Instead, the sugar is circulated in the blood and then eliminated in the urine. In order to make energy, the body starts to use another method to produce energy, which can result in muscle loss and a severe medical condition called ketoacidosis.

A word about healthy weight loss in obese cats:

It is a good idea to encourage weight loss in overweight senior cats, to avoid problems such as arthritis, diabetes, high blood pressure, or other heart and respiratory complications.

Just like with humans, there is no easy quick weight-loss miracle - getting a cat to lose weight in a healthy way takes time, and a combination of diet and exercise. An overweight cat on a weight loss plan should not lose more than half a pound in four weeks. 

One pound of weight loss may not seem like much, but for a 10 pound cat, it is 10% of its body mass - that's equivalent to 15 lbs. in a 150lb. human.  

The American Veterinary Medical Association recommends wellness exams every 6 months in senior cats because they age much more quickly than humans do. If you have noticed that your cat is losing weight or if it has been more than 6 months since your senior kitty’s last exam, it might be time to schedule a checkup!