Hypertension in Cats: Causes and How to Treat
High blood pressure or hypertension is a common disease for aging felines. The condition occurs when the cat’s blood pressure is consistently higher than normal. Typically, hypertension is a secondary condition to other disease processes in the body so frequently if a blood pressure is consistently high the first step is lab work. Chronic kidney disease, hyperthyroidism, and heart disease can all lead to high blood pressure.
What are the clinical signs of hypertension?
In many cats, there are no signs or symptoms and if there are it’s usually not 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 stressed, and can even suffer from sudden blindness.
When the hypertension results from other underlying conditions, such as a 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 the different organs?
If left untreated for a long time, high blood pressure can damage your cat’s internal organs, which makes it essential to detect high blood pressure early and start treatment as soon as possible. Here are the potential side effects if high blood pressure is left untreated:
- 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 was 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 also increase the risk of developing kidney failure. The small blood vessels in the kidney cannot withstand the high pressure and become increasingly more 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. Our goal at Just Cats Clinic is to catch changes in blood pressure early on so we can determine the cause before further damage occurs. For senior patients, we check blood pressures at each senior exam every 6 months. For cats that have risk factors such as heart disease, hyperthyroidism or kidney disease, we’ll recheck a blood pressure at every visit.
While we try to make your cat’s vet visit as stress free as possible, there is still an element of stress that typically factors into your cat’s blood pressure reading. At Just Cats it truly depends on your particular cat’s case and demeanor but here’s the general guideline we follow:
150 – Watch and recommend doing labs to ensure we aren’t missing an underlying disease
Consistently over 160 – Time to treat for high blood pressure. Consistent readings over 160 indicate that there is something going on beyond stress and warrants treatment to minimize stress on the heart.
180 – Treat – even with stress as a factor, most cats will not elevate their blood pressure this high on their own
How is hypertension treated?
After determining that your cat is suffering from hypertension, we will try to address any complications that have occurred. Then we’ll 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 will be essential in treating the hypertension itself.
We’ll likely prescribe some anti-hypertensive drugs to help regulate your cat’s blood pressure. Dosing can be tricky so during the initial trial of medication, we’ll likely recheck your cat’s blood pressure several times to ensure we have the correct dose. Once your cat is on anti-hypertensive drugs and regulated, we’ll closely monitor its blood pressure and watch for any ocular changes.
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 complications to other organs. If the hypertension is caused by an underlying disease, the long-term prognosis depends on what kind and how severe the disease is. If this is the case it’s important to treat the disease and the high blood pressure simultaneously.