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High blood pressure (hypertension) is a problem not just limited to humans. Animals can be subject to this disease as well. There are two common classifications of hypertension. Primary hypertension is a problem that is infrequently seen in pets. Secondary hypertension is much more prevalent. Secondary hypertension is a condition where the high blood pressure is secondary to another disease process. In cats, this is often seen in patients with kidney disease, heart disease or hyperthyroidism. These conditions create hypertension through different means but the end result can have deleterious effects on other organ systems. The following are a few examples.
Hypertensive Retinopathy – This is a condition where the blood vessels of the retina become distended and can potentially rupture leading to blindness. The feline species is especially susceptible to this effect as their retinas are quite vascular. Cats will present with evidence of bleeding into the eye or a detached retina from bleeding behind the retina. This can be catastrophic and is a medical emergency. Blood pressure must be lowered quickly if vision is to be restored.
Hypertrophic Cardiomyopathy and Other Cardiac Effects – The heart is significantly affected by hypertension. With high blood pressure, the heart has to work harder and it can manifest in the buildup of muscle tissue within the heart. Thus, a heart affected by hypertension is prone to heart muscle changes and abnormal heart rhythms leading to cardiac failure.
Kidney Disease – Although hypertension can be secondary to renal disease, it also can exacerbate the decline of this organ. Multiple studies have shown that cats in early states of renal disease are more prone to hypertension.
Neurologic Disease – Animals are often affected neurologically by hypertension usually secondary to bleeding.
Diagnosis and Treatment
Diagnosis of hypertension is done with the same instrumentation used in human medicine. It can be challenging in the feline patient as they are highly susceptible to “the white coat effect” – the stress of being in the hospital falsely elevates a patient’s pressure. For this reason, it is recommended to minimize a cat’s stress prior to the exam or better yet, have a mobile service come and obtain a blood pressure at home. This allows for less stress for the patient and better data for your veterinarian.
Treatment can be accomplished through two main types of medications: Calcium channel blockers and angiotensin-converting enzyme (ACE) inhibitors. These drugs work by relaxing and dilating the animal’s blood vessels. With these medications, hypertension is usually controllable and ultimately reversible if the underlying disease is properly addressed.
Jeb Mortimer, DVM
Green Lake Animal Hospital