How to Know if Your Cat Has Hypertension

This is a sponsored post by veterinarian Elizabeth Arguelles, owner of Just Cats Clinic at Lake Anne Plaza. She writes weekly on Reston Now.

High blood pressure (hypertension) is a common disease in both humans and cats. The condition is defined as occurring when the cat’s blood pressure is consistently higher than normal. Generally, that means above 175 mmHg. Hypertension most frequently affects older cats, and results from other underlying medical conditions. Chronic kidney disease is often such a cause, but there are also other diseases that can trigger hypertension, including hyperthyroidism and heart disease.

What are the clinical signs of hypertension?

In many cats, there are no signs until the hypertension has become quite severe. When the condition reaches that point, abnormalities in the cat’s vision are the most common indicators. Examples of these include dilated pupils that do not constrict with light, blood in the eye chambers and/or blindness.

It may seem odd that blindness is a symptom of high blood pressure, but the loss of vision happens when the hypertension causes the retina to detach from the cat’s eye. Owners often notice that their cat is vocalizing oddly, restless or seems stressed, and even that they seem to be suffering from sudden blindness.

When the hypertension results from other underlying conditions, such as heart, thyroid or kidney disease, the symptoms could include increased water intake, increased urination, vomiting and weight loss.

What are the effects of hypertension on organs?

If left untreated for a long time, high blood pressure damages a cat’s organs, especially those that are considered more vulnerable than others. Those include:

• The brain and nervous system: Hypertension can cause bleeding in these areas of the body, which can lead to neurological symptoms such as wobbly gait, dementia, seizures or coma.
• The eyes: As mentioned above, high blood pressure can cause changes to and even detachment of the retina. This may result in sudden blindness.
• The heart: Because the heart has to work harder to pump blood, the muscle may thicken over time. In very severe cases, this could result in heart failure and difficulty breathing.
• The kidneys: In addition to being a symptom of chronic kidney disease, high blood pressure can increase the risk of developing kidney failure. The small blood vessels in the kidney cannot withstand the high pressure and become increasingly damaged.

How is feline hypertension diagnosed?

Because hypertension is only apparent at more serious stages, such as the sudden onset of blindness or neurological abnormalities, it is important to be proactive and get your cat’s blood pressure checked regularly. If your cat is older than 7 years old, the checks should be performed twice a year. In cats suffering from chronic kidney disease, hyperthyroidism or heart disease, blood pressure should also be carefully assessed and monitored.

How is hypertension treated?

After determining that your cat is suffering from hypertension, your vet will try to address any complications that have occurred. He or she will then assess whether the high blood pressure is caused by another disease. If the hypertension is due to an underlying disease such as chronic kidney failure, treatment of the main disease may also help control the high blood pressure.

If the hypertension is not secondary, anti-hypertensive drugs will likely be prescribed for your cat. Once your cat is on anti-hypertensive drugs, your vet will closely monitor its blood pressure and watch for any changes to its eyes.

What is the prognosis for hypertension?

Most cats with hypertension will need long-term therapy and management. If the hypertension is not caused by any underlying disease, it is usually possible to manage and control the high blood pressure and prevent further damage to organs. If the hypertension is caused by an underlying disease, the long-term prognosis depends on what kind and how severe the disease is.

For more information please visit our Feline Health Library, petMD and this guide to feline chronic kidney disease.