Hypertension

Hypertension is high blood pressure. The normal systolic blood pressure in dogs and cats can vary but is usually below 150mm/Hg. We generally start treatment for hypertension when the blood pressure is increased above 170m/Hg.

It is very common to have your blood pressure measured when you visit the doctor. However, it is rare that blood pressures are measured in animals. Measuring blood pressure is much more difficult in animals than in humans, and requires quite different equipment than is used in man.

Causes of increased blood pressure

1. Kidney disease The kidneys regulate blood pressure. As the kidneys begin to fail the blood pressure can increase. Signs of kidney disease may include weight loss, increased thirst, and increased urination.

2. Endocrine (hormonal) disease The most common disease is Hyperthyroidism, in cats. It is generally due to hyperactivity of the thyroid glands. Signs of Hyperthyroidism include weight loss, increased appetite and increased activity. Other endocrine diseases can include Diabetes and Cushing’s disease.

3. Idiopathic – no obvious cause can be found This is also known as essential hypertension. Some of these cats when tested later have developed kidney problems.

In order to find any underlying cause(s) of hypertension we recommend blood tests & urinalysis. Generally this is done at your local veterinary clinic.

Treatment

1) Oral medication A calcium channel blocker seems to work very effectively in controlling hypertension. It is given once daily, and seems to have few, if any, side effects. We generally check the blood pressure 2 to 3 weeks after starting treatment. In most cases the blood pressure is very well controlled. In some this medication alone does not control the blood pressure we need to add another drug to the treatment regime.

2) Treatment of any underlying cause If the blood tests find that the kidneys are diseased or the thyroid level is high, your local veterinarian will manage treatment for this.

We will need to regularly check the blood pressure. Please make sure that you do not stop treatment. The increased blood pressure can cause other diseases such as stroke and heart failure.

Eye signs of increased blood pressure

High blood pressure can cause retinal detachments and retinal/vitreal haemorrhages (blood in the eye). There is no specific treatment or surgery for these conditions. Generally by controlling the increased blood pressure the eye signs will improve. It may however take months for the blood to clear from the eyes.