Kidney disease, especially in the chronic stages, is one of the most common causes of persistently high blood pressure, or hypertension, in dogs. Other underlying diseases, such as Cushing’s disease (elevated adrenal hormones) can also increase blood pressure. If no underlying disease is found, the hypertension is considered primary, or idiopathic, meaning the cause is unknown.
Left untreated, high blood pressure can lead to tissue damage in organs including the eyes, heart, brain, and even the kidneys. That’s why it’s important for dogs with chronic kidney disease to have their blood pressure checked on a regular basis.
The kidneys and blood pressure
Healthy kidneys are an important part of the body’s regulatory system since they help maintain normal blood pressure, or the force exerted by blood against the vessel walls. Disease can compromise kidney function, leading to an uncontrolled increase in blood pressure. At the same time, hypertension can make kidney disease worse.
Signs of hypertension
Many dogs show no signs of high blood pressure. But hypertension can affect the eyes, causing the retina — the lining in the back of the eye — to become detached, leading to sudden or gradual blindness. In some cases, if the problem is caught quickly, blindness can be reversed. In other cases, the damage is permanent. Dogs may also deal with dilated (enlarged) pupils.
Dogs with hypertension may experience neurological signs such as seizures, disorientation and difficulty walking. The condition puts additional pressure on blood vessels and the walls of the heart, potentially causing damage there. Your veterinarian may hear a heart murmur when listening through the stethoscope. Abnormal blood flow can also increase the risk of blood clot formation and stroke.
How is blood pressure measured?
The unfamiliar sights, sounds and smells of a veterinary clinic can cause a pet’s blood pressure to rise temporarily. That’s why it’s important to allow dogs to acclimate in a quiet room before any readings are taken.
For dogs, blood pressure is measured by wrapping an inflatable cuff around the limb or tail that uses a Doppler flow meter or an oscillometer to measure the pressure. Blood pressure is typically described with two numbers: The systolic pressure, which is the higher blood pressure in the arteries when the heart contracts, and the diastolic pressure, which is the lower pressure in the vessels when the heart fills with blood.
Systolic readings above 160 mmHg (millimeters of mercury) or diastolic readings above 120 mmHg typically trigger the need for medication. Dogs with systolic readings over 180 mmHg may need emergency treatment to help prevent organ damage.
Several readings should be taken before a diagnosis is made.
Calming the pressure
If your dog is diagnosed with hypertension, controlling the underlying kidney disease, or slowing disease progression, can help manage blood pressure. Medications may also be recommended.
Feeding a renal diet that’s low in sodium can also be helpful.
Even if your dog is on blood pressure medications, you’ll want to watch for possible signs of hypertension. Your veterinarian will probably recommend checking blood pressure readings periodically to make sure it remains in the healthy range.
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