BLOOD PRESSURE CHECKS

Frequently, I am asked if pets suffer the same conditions as people. Many conditions are common to both animals and humans, these conditions are called zoonotic. This generally refers to infectious diseases, but many non-infectious conditions are common to all species.

One of these conditions is high blood pressure or systemic hypertension. Blood pressure is the measured pressure on the artery walls as the heart beats, during contractions when it empties and on during relaxation when it fills with blood. The heart contraction is called systole and the relaxation is called diastole, so when you have your blood pressure taken, the two figures given are the maximum and minimum pressures, e.g.120 over 80.

Causes of high blood pressure in pets can occur for the same reasons as in humans. Occasionally it may be primary, with no known cause. Generally secondary hypertension is due to kidney disease, adrenal gland disease in dogs or overactive thyroid in cats. Diabetes, some tumours and some brain conditions can also cause hypertension, though rarely. There are many different reasons why dogs and cats may develop hypertension.

When it comes to measuring blood pressure, we do this in a very similar way to you having your blood pressure taken. We do try to get our pets calm before taking blood pressure readings. Just like us, our pets are prone to “white coat syndrome” (or green coat at Dunedin Vets). Being at the surgery can cause stress which can artificially raise their blood pressure. We usually ask owners and their cats to come 15 to 30 minutes early for their appointment, so they can relax in a quiet room before the reading. It is good for dogs to be with their owner who can help relax them. A small area of fur is clipped from behind the carpus (wrist) of a forelimb. A cuff is applied round the limb just below the elbow. A sensor is applied to the clipped area and the cuff inflated. Your vet or vet nurse will listen for the pulse and determine the blood pressure. This gives the highest or systemic pressure. It is difficult to determine the diastolic pressure. A slight change in sound tone can determine the diastolic pressure. Levels of over 140 mmHg in dogs and 180 in cats, over several readings are deemed to be systemic hypertension.

At Dunedin Vets, Tranent branch, we have a lovely cocker spaniel called Sam who is Mrs Muir’s special pet, he comes regularly for blood pressure checks. Now Sam was diagnosed with renal (kidney) disease some time ago. He is an older boy at 13 years old, so we want to monitor how the condition is developing. He has had regular blood tests and we have been monitoring his blood pressure. He is such a patient dog and not apparently stressed by the procedure, but when I first measured his blood pressure, I was extremely surprised when it read 280 mmHg. Myself and nurse looked at each other, thinking that’s not right, but we repeated the procedure and sure enough, Sam’s systolic blood pressure was constantly 280, his diastolic was around 160. This is the highest blood pressure I have ever recorded. Generally dogs very rarely have blood pressures In excess of 200. (Cats are more likely to be this high). I was obviously very concerned about this, as systemic hypertension can result in a number of serious conditions.

One of the commonest signs of hypertension is bleeding inside the eye. This is a very common finding in cats with hyperthyroidism, who often present at the surgery with large dilated pupils and are blind. They may have detached retinas too which will probably mean the blindness is permanent. There may be signs related to kidney problems such as increased thirst and passing urine more often. Sometimes there can be blood produced in urine. As the blood pressure remains high, bleeds or haemorrhages can occur such as nose bleeds. Often the heart is affected, with murmurs developing or worsening or irregular heart rhythms occurring. Sam has been in amazing health apart from his kidney disease, he is showing no adverse effects of his hypertension. Unfortunately some animals with hypertension can have problems with their nervous system. They may develop head tilts and be wobbly and disorientated. They may be depressed and uncoordinated or even partly paralysed. Some develop odd movements of their eyeballs, called nystagmus. These are signs associated with a CVA (cerebral vascular accident) or a “stroke”. These are obviously very distressing symptoms for both pet and owner. The aim is therefore to reduce the hypertension and hopefully reduce the symptoms.

The treatment will depend on the underlying cause. So dogs with renal problems are prescribed drugs and special diets to assist kidney function. These drugs include ACE inhibitors, beta blockers and calcium channel blockers. Cats with hyperthyroidism are given medication to help this, or they may require surgery or even radiotherapy to assist their thyroid function. Sam has been prescribed a drug to dilate his blood vessels and so reduce his blood pressure as well as a drug to help his heart pump blood around his body. We are slowly increasing his doses so that he does not suddenly develop a drop in blood pressure which could cause him to collapse. So far he is responding well. Sam continues to have his blood pressure checked at regular intervals. He also has regular blood tests to monitor his kidney function. Once animals start on medication, it is generally for life. They need constant monitoring to ensure the condition is not deteriorating. I know many people with high blood pressure are concerned about their condition, which can make matters worse. As far as I am aware our pets do not concern themselves with their condition so the medications work very well. There is no reason why a pet with systemic hypertension cannot have a happy and enjoyable life, as long as they keep taking the tablets. We wish Sam all the best and hope we can reduce his record breaking blood pressure to a reasonably normal level in the near future.