What is High Blood Pressure?
High blood pressure refers to the force of the blood pushing against the arteries with a continuously elevated force. Just as in humans, cat blood pressure has an average healthy value, and can be measured. It is best to check your cat's blood pressure routinely during regular visits to the vet so that any problems due to changes in blood pressure can be prevented.
In rare cases, the cat's elevated blood pressure has no associated underlying cause. This is called primary or idiopathic hypertension. In most cases however, a diagnosis of secondary hypertension is made, meaning that the cat's high blood pressure indicates another underlying primary disease. Older cats seem to be more prone to hypertension, though cats of all ages develop this condition.
High blood pressure, or hypertension, is a relatively common but manageable condition in cats. If left untreated, hypertension is a severe threat to the cat's health and can cause serious damage to the eyes, nervous system, kidneys, and heart.
Symptoms of High Blood Pressure in Cats
Unfortunately, there are no early warning signs of high blood pressure, and many cats with high blood pressure will exhibit no signs at all until the condition is severe. The symptoms they exhibit vary due to the underlying disease causing the high blood pressure.
If the primary disease is hyperthyroidism or chronic renal failure, the cat might exhibit:
- Dull coat
- Loss of appetite
- Increased thirst
- Increased urination
- Weight loss
If uncontrolled high blood pressure in the cat goes unnoticed for a lengthy period, the cat might experience:
- Burst blood vessels in eye and sudden blindness
- Retinal detachment
- Enlarged thyroid gland in neck
- Difficulty walking
- Difficulty breathing
- Heart murmur
Causes of High Blood Pressure in Cats
Most cats with high blood pressure have an underlying primary cause. Two of the most common causes are acute hyperthyroidism and kidney disease.
Other causes are:
- Overproduction of aldosterone, an adrenal hormone
- Adrenal gland tumors
Diagnosis of High Blood Pressure in Cats
A preliminary diagnosis is made by measuring the cat's blood pressure by placing a cuff on the leg or tail. Two measurements are made: the systolic pressure, the pressure in the arteries when the heart contracts or beats, pumping blood, and the diastolic pressure, the pressure when the heart rests between beats and fills with blood. In addition, a full blood workup will be done to discover the underlying cause. Most vets will also take a urinalysis and assess the thyroid hormone level.
Treatment of High Blood Pressure in Cats
Treatment is initiated if the blood pressure elevation is found to be severe. The first step is to address any underlying disease such as chronic renal failure (CRF) or hyperthyroidism. Common treatments include medications that work to relax and widen the cat's blood vessels and reduce the resistance to blood flow. Calcium channel blockers and angiotensin-converting enzyme (ACE) inhibitors are the main types of medication. Diuretics might also be administered, which lower the body's fluid load, thereby lowering the blood pressure. With these types of medications, high blood pressure is controllable and sometimes reversible.
Diet is another method of treating hypertension. Most affected cats are placed on a low-sodium diet. If a cat is obese, the vet will prescribe a weight-loss diet and regimen. Both you and your cat will monitor the progress of the weight loss program.
Once treatment is started, your vet will monitor the cat's blood pressure to see if it improves and to make sure that it does not drop too low. In extreme cases, a cat may need to be hospitalized for close monitoring until the crisis condition is stabilized. In a crisis situation, medication will be administered intravenously. Otherwise, oral medication is appropriate.
Recovery of High Blood Pressure in Cats
The management of high blood pressure in cats is centered around reducing the cardiac output and the dilation of the blood vessels. Both medication and lifestyle measures, including diet, are prescribed. Proper nutrition for your cat's breed and condition is very effective in addressing both the underlying disease and the manifest symptoms. If your cat's diet is balanced, it should already be getting enough vitamin C and E, but if not, they can be taken synthetically. Vitamin C and E are both helpful in lowering blood pressure.
Though it can be hard to get your cat moving, exercise is important in cats just as it is in humans. Since obesity often causes hypertension, daily movement and aerobic activity are suggested.
Another lifestyle measure that is recommended is keeping your cat's environment and routine as stress-free as possible. Cats thrive on consistent and calm environments, especially when already dealing with a stressful health challenge.
In cats which high blood pressure is detected early on and a therapeutic program is started immediately, it is usually possible to manage the disease well and prevent any future complications like eye damage.
High Blood Pressure Questions and Advice from Veterinary Professionals
Olive is 12, spayed (after kittens weaned 11 years ago.) She was diagnosed with hyperthyroidism 2 years ago and has been stable on methimazole. Recently her pupils have been usually dilated, no apparent loss of vision. BP yesterday 190/120 so will be starting on meds. Would like more information re the med but seems to be little information available---is med for humans? What effects/side effects might occur?
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Hi, my cat Zeezuu who had been on thyroid medication has suddenly gone blind. I took her to the vet yesterday and they confirmed what I had thought. Her pupils were dilated. When they shone light into her eyes they didn’t retract and get smaller. The vet said the retina has not detatched and gave me some prescription medicine for high blood pressure, as it was extremely high. Today her eyes not as dilated when I place light into them, they retract but are still not completely normal, they are thick but do get slightly smaller. I have shone a torch in her eye and when it is pointed closely she closes her eyes. I am hoping for the best, my question is since the retina has not detached, can her eye sight return? Is it a good sign that when I shine light in her eyes she closes them, even though it is very near, and that her dilated pupils have gone slightly smaller? I don’t want to get my hopes up, but jus can’t sleep if I don’t find out.
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