22 Park Street Mona Vale, NSW 2103

Understanding Hypertension in Cats – Causes, Risks, and Treatment

Jan 23, 2025

What is feline hypertension?

Blood circulation is essential for life in both humans and animals. It delivers oxygen and nutrients to the body’s tissues and cells, removes waste products, and helps regulate body temperature.

For blood to reach all organs and parts of a cat’s body, it must be pumped through blood vessels by the heart. The pressure exerted by the heart’s pumping action is known as blood pressure. When this pressure remains consistently elevated above normal levels, it is referred to as high blood pressure or hypertension.

What causes hypertension in cats?

When a cat is diagnosed with high blood pressure, it’s crucial to identify any underlying health issues. In some cases, the cause remains unknown, and this type of high blood pressure is called primary hypertension.

However, most cats experience secondary hypertension, where the high blood pressure is linked to or caused by another medical condition. The most common causes in cats include:

  • Chronic kidney disease, or
  • Hyperthyroidism

In rare instances, other conditions, such as those affecting the adrenal glands (where excessive production of hormones like cortisol, aldosterone, or catecholamines may occur), can also contribute to high blood pressure.

Which cats are at risk for developing hypertension?

Older cats, particularly those over 7 years of age, are more likely to develop hypertension. For this reason, most veterinarians recommend measuring blood pressure during routine visits for cats starting at 7 years old.

Cats diagnosed with underlying conditions that can lead to hypertension are also at an increased risk. Even if their condition is well-managed, regular blood pressure monitoring is still advised.

What are the consequences of high blood pressure in cats?

Hypertension is often a “silent” condition, with few noticeable symptoms in the early stages. However, it tends to worsen over time, leading to serious and potentially life-threatening complications.

High blood pressure can damage various organs in the body, but there are four key organs, known as “target organs,” where the damage is most commonly observed:

  • Kidneys: Hypertension can cause severe, irreversible kidney damage. In
  • humans, it is a known cause or contributor to chronic kidney disease (CKD), and it is believed that the same may be true for cats.
  • Eyes: Hypertension can lead to bleeding in the eye and/or retinal detachment. Sudden blindness is one of the most dramatic consequences of high blood pressure in cats.
  • Heart: High blood pressure can cause thickening of the heart’s muscular wall, as the heart works harder to pump blood against higher pressure in the vessels. This can impair heart function and efficiency.
  • Brain: Hypertension can cause damage to the brain and central nervous system. Symptoms may vary but can include behavioral changes, depression, or even seizures.

The extent of damage caused by hypertension depends on factors such as the severity of the blood pressure, how long it has been elevated, and how well the cat tolerates it. Nonetheless, high blood pressure is a significant health risk and a major welfare concern, especially for older cats.

How can hypertension be recognised?

Unfortunately, hypertension can remain undetected for a long time, with symptoms often appearing only after significant damage to organs and a noticeable decline in the cat’s quality of life. This is why hypertension is often referred to as a “silent killer.”

Many cat owners may not notice any issues until their cat suddenly becomes blind, develops neurological problems, or exhibits signs of another underlying condition. Staying vigilant and observing early signs of illness—such as changes in appetite, thirst, or body weight—can help facilitate the early detection of hypertension and any associated underlying diseases.

How is high blood pressure diagnosed in cats?

Hypertension is diagnosed by measuring your cat’s blood pressure. Early detection is crucial to begin treatment and prevent damage to sensitive organs. Regular blood pressure checks, ideally once or twice a year, are recommended for senior cats (those over 7 years old) to catch hypertension early.

If your cat is stressed or anxious during a vet visit, it can cause a temporary rise in blood pressure, known as the “white-coat effect.” Veterinarians use various techniques to minimize stress and other factors that could affect blood pressure readings, often including multiple measurements over different visits to ensure accuracy.

How is blood pressure measured?

We measure your cat’s blood pressure in a similar way to how your doctor measures yours! We place an inflatable cuff around your cat’s leg or tail and uses a sensitive device to detect blood

flow. By inflating the cuff and monitoring the blood flow as the pressure is gradually released, we can obtain a blood pressure reading. Just like in human medicine, ou team has access to various types of equipment for this procedure.

How is hypertension treated?

Similar to humans, hypertension in cats is typically managed with daily medication to lower blood pressure (known as ‘anti-hypertensive’ drugs). This helps control the blood pressure and prevents or manages damage caused by high pressure.

Treatment plans will vary depending on factors such as the underlying cause of the hypertension, the severity of the blood pressure, and whether any organ damage has occurred.

It is also crucial to diagnose and treat any underlying conditions. In a small number of cases, addressing the root cause may resolve the hypertension, allowing the discontinuation of anti-hypertensive medications.

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