Feline hypertension, the medical term for high blood pressure, is usually seen in older cats, and is most often secondary to an already existing disease such as kidney failure, heart disease, or hyperthyroidism. Accurate diagnosis and treatment are important to prevent serious consequences.
High blood pressure is known as the silent killer, because by itself, it has no symptoms. High blood pressure causes wear and tear on the heart and kidneys. It can cause small blood vessels to leak and rupture. If this happens in the eye, it can lead to blindness. If it happens in the brain, it can lead to a stroke.
Obtaining an accurate blood pressure measurement on cats can be challenging. Most cats are stressed when they visit the vet, and stress elevates blood pressure. There’s even a name for this in human medicine: “white coat syndrome.” This is a phenomenon in which patients exhibit elevated blood pressure in a clinical setting, but not in other settings, and it applies to cats as well.
Blood pressure in cats is measured the same way it is measured in humans: with an inflatable cuff and an ultrasonic listening device called a Doppler. In order to minimize stress during this non-invasive test, it helps if it is done in a quiet room, away from barking dogs and other noises. Usually, having the cat’s guardian present can help calm the cat. The vet will take several readings, to rule out the above mentioned white coat effect as much as possible.
If blood pressure is consistently high after taking several measurements, additional tests will be necessary, including, at a minimum, a complete bloodcount, blood chemistry, and urinalysis.
Cats who have one or more of the following conditions are at risk for elevated blood pressure:
- Chronic renal failure and other kidney disease
The decision whether to treat hypertension should be based on reliable, repeatable blood pressure readings, and will be influenced by any concurrent disease. Vets must take the cat’s temperament and anxiety level into consideration when interpreting blood pressure test results. Normal cats often have transient elevated blood pressure due to the stress of being at the vet’s and the exam itself. The treatment decision will also depend on an individual cat’s risk factors.
Treatment will first target the underlying disease. Medications that can exacerbate hypertension, such as steroids, will need to be eliminated or reduced. Excessive sodium in the diet should be avoided, but a low salt diet is not necessarily indicated. Maintaining normal potassium levels is important, and a low salt diet can lead to loss of potassium without any beneficial effects on blood pressure.
If treatment is indicated, the type of drug used will depend on the overall diagnosis. The goal of treatment is to reduce blood pressure into a range that minimizes organ damage. Once blood pressure is controlled, it should be rechecked every three months.
Cats in a hypertensive crisis (severe neurological symptoms or sudden onset blindness) will need emergency treatment and will usually require hospitalization and careful monitoring. The prognosis for these cats is variable. Some cats with sudden onset blindness will recover some of their lost vision if treatment is initiated soon enough.
The American Association of Feline Practitioners recommends blood pressure monitoring as part of a regular bi-annual senior cat exam in their Senior Care Guidelines.
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