Browsing tag: blood pressure

Could your cat have high blood pressure?

High blood pressure is a common problem for humans but did you know that cats can get it too? High blood pressure, also known as hypertension, is actually quite common in older cats, especially those with other diseases such as kidney disease or hyperthyroidism. The symptoms can be quite subtle or mimic those of other diseases so many cases remain undetected for quite some time. If left untreated, however, hypertension can lead to significant secondary health problems, so it’s definitely worth testing for.

Bob having his blood pressure checked.

Bob having his blood pressure checked.

What exactly is high blood pressure?

High blood pressure occurs when the pressure within the blood vessels exceeds a certain threshold. Think of the hosepipe used to water your garden. If you turn the tap on too strongly, the water shoots out of the nozzle uncontrollably, damaging your flowers. The same is true for the body – organs like the brain and kidneys need blood to survive but if the blood pressure gets too high, it can start to damage the very organs it is trying to keep alive. To further complicate things, blood vessels have a tendency to leak under pressure and this extra fluid can cause further problems.

How do cats develop high blood pressure?

Many things can cause hypertension in cats from certain medications to neurological disease, but the two most common causes are kidney failure and hyperthyroidism. Both of these illnesses cause alterations in the very precise mechanisms that monitor and control blood pressure. It doesn’t always correlate with the severity of the disease (i.e., severe hypertension can be seen with only mild kidney disease) and in the case of hyperthyroidism, we sometimes see hypertension develop only after the thyroid problem has been treated.

What are the symptoms of hypertension?

The clinical signs associated with high blood pressure depend on which organs are most badly affected. One of the most common signs is acute blindness because the high pressure within the vessels of the eye causes the retina to detach from the nerves that tell the brain what the eye is seeing. So you may notice the cat bumping into things (although it’s amazing how many owners aren’t aware of their cat’s blindness because cats are so good at using their other senses to compensate), staying closer to home or having very dilated pupils or ‘wide eyes’. Another organ that is commonly affected is the brain so you might see serious signs such as circling and seizures or perhaps much more subtle behavioural changes such as crying out at night or being less sociable when people are around (how else would you tell if your cat had a headache?). You may see bleeding in unexpected places like nosebleeds or blood in the urine. It can also speed up the progression of kidney failure. The list goes on so any unexplained physical or behavioural change warrants a blood pressure check, especially in older cats.

How is high blood pressure diagnosed?

The only way to tell if a cat has high blood pressure is to measure it. The process is much the same as it is in humans – a cuff is inflated around the arm or leg (or possibly the tail) which controls blood flow to the limb. A special device (sometimes a handheld Doppler unit or sometimes an automatic sensor) then measures the blood pressure. It doesn’t hurt and isn’t usually a stressful process that is good because if the cat is stressed the reading can be artificially elevated. Sometimes the cat objects to the cuff being tightened so it can help to practice a few times before taking the reading. Some cats just plain hate going to the vet or any kind of restraint whatsoever so it isn’t always possible to get a reading, although many clinics have special protocols in place to help the cat stay as calm as possible before attempting to take a blood pressure. If all else fails in the clinic, a reading might be possible at home where they are more comfortable.

Is there any treatment?

Absolutely. There are several medications that can treat high blood pressure but the one that most vets use these days is called amlodipine. A very tiny dose goes a long way, and it’s important that once you start the medication, you give it regularly to avoid dangerous spikes in blood pressure. Once a cat starts the medication (usually a tiny tablet that most cats seem to tolerate relatively well) it’s important to follow up with regular blood pressure checks to ensure that they are on the correct dose.

I’ve seen many cats respond very well indeed to treatment and many owners report that their cat seems years younger once their blood pressure is under control, even if they hadn’t noticed any symptoms in the first place. It is yet another example of how well cats can hide their illnesses and how important it is for owners and vets to work together to detect health problems while there is still time to treat them effectively.

If you think your cat is showing signs of high blood pressure or if you have an older cat with unexplained physical or behavioural changes, please speak with your vet about having their blood pressure checked. You may never know unless you make an effort to look for it.

Amy Bergs DVM MRCVS  - Visit The Cat Doctor website by clicking HERE

Why cats go blind.

Blind cat showing dilated pupils

Blind cat showing dilated pupils

One of the most common causes of sudden blindness in an elderly cat is due to high blood pressure (hypertension). The increased pressure pushes the light sensitive layer (retina) away from the back of the eye and this can happen literally overnight.

The affected cat will have very widely dilated pupils even in bright sunlight and there might be some blood visible when looking into the eyes. They will appear to be disorientated, bump into things and might vocalise excessively.

Monitoring a cat's blood pressure

Monitoring a cat's blood pressure

The usual cause of raised blood pressure in cats is an excess of thyroid hormone (hyperthyroid) but it can also be due to kidney disease or diabetes. This is why it’s important for the vet to take blood tests to decide which condition to treat.

We monitor cats’ blood pressure in a similar way to human doctors by inflating a cuff just above the paw on a front leg but we listen for blood flow with an ultrasonic probe rather than a stethoscope. Some cats are calmer if the cuff is placed around the tail base. A few readings are usually taken to make sure that the blood pressure has not been raised through stress.

blood pressure kit

Blood Pressure Monitor

Drugs are very successful in bringing a cat’s blood pressure down to normal but the blindness is usually permanent. Cats are extremely adaptable when it comes to finding their way around the house and finding their food but they are not safe to allow outside due to all the dangers out there.

There are a number of other causes of blindness but these generally come on more slowly:

Glaucoma is the same condition as people get where there is an increased pressure within the cat’s eye. This is usually seen as a very angry painful eye and the white of the eye appears red due to the many new blood vessels. Drops can control the condition if caught early enough but if it reaches the stage where the eye is visibly swollen or ulcerated, then removal of the eye (enucleation) will usually be suggested. Glaucoma can be found in just one eye or both.

Cataracts are much less common in cats than dogs and would be seen as a misty or pearly lens. Tests would be required to rule out diabetes which can be a cause.

Tumours within the cat’s eye are occasionally discovered when the eyes are examined with an ophthalmoscope. Loss of vision would be slow to develop in these cases and often in only one eye initially.

If you have a pedigree cat (particularly an Abyssinian) who starts to slowly lose vision early in life, there is a possibility of Progressive Retinal Atrophy (PRA) which is a genetic disease, very similar to the condition in some pedigree dogs. There is no treatment but the cat usually has time to adapt to the slow loss of vision.

Something we hardly ever see these days is Taurine (an amino acid) Deficiency. Modern complete diets have all the taurine a cat needs but it is just possible that a cat fed exclusively on tinned tuna could develop slow onset blindness due to this deficiency. If caught early enough, the loss of vision can be stopped or even reversed.

Most cats adapt very well to blindness and go on to enjoy a good quality of life. Some adapt so well that it would be hard for a casual observer to know they were blind.

If you are worried about any problems with your cat’s eyes, please contact your vet or use our interactive Cat Symptom Guide to help you decide what to do next.

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