Hypertension is the medical term for high blood pressure, and, just like humans, the blood pressures of cats and dogs can rise to dangerous levels.
The top number in a blood pressure is known as the systolic blood pressure. A normal systolic blood pressure for cats and dogs is between 120 and 130 mm Hg (also just like humans). Once systolic blood pressure reaches 160 mm Hg, an animal is considered to be hypertensive, although an extra allowance is given because of the stress pets can experience in a hospital setting, also known as the “white-coat effect.”
While both cats and dogs can become hypertensive, it is a disease more commonly seen in cats, especially senior kitties.
Causes of hypertension
Hypertension is typically a side effect of an underlying health condition or medication that is causing the blood pressure to rise. Hypertension can be caused by:
- Kidney disease
- Heart conditions
- Thyroid issues
- Cushing’s disease
- IV fluid therapy
Hypertension in cats is most commonly attributed to kidney disease and hyperthyroidism.
Chronic renal failure is the most commonly associated disease with high blood pressure in cats. Hypertension has been seen in up to 65 percent of cats diagnosed with kidney disease. One theory behind why this happens suggests that as a cat ages, the kidneys develop scar tissue due to normal, age-related changes. This causes the kidneys to shrink, making it much more difficult for the blood to pump through this pathway. The kidneys hold an astounding 20 percent of the body’s blood during the circulatory process. If they’re damaged, that blood will back up into the arteries, which causes an increase in blood pressure. Sadly, hypertension worsens kidney disease, and it becomes a vicious cycle, with each disease increasing the severity of the other.
Hyperthyroidism is defined as the overproduction of thyroid hormones by the thyroid gland. This excess of hormones stimulates the heart, causing it to pump harder and faster, which only serves to raise the output of blood and the blood pressure. About 25 percent of cats with hyperthyroidism also have hypertension, but once the hyperthyroidism is managed, the hypertension typically resolves in the following weeks or months.
Signs of hypertension
Cats suffering from high blood pressure might experience:
- Vision issues
- Dilated pupils that do not constrict with light
- Blood within the chamber of the eye
- Blindness due to a detached retina
- Kidney or liver disease
- Drinking more
- Urinating more
- Weight loss
- Behavioral changes
- Nose bleeds
- Congestive heart failure/murmur
- Stroke-like symptoms
Hypertension can be a “silent killer.” No signs may be noticed, and it may be the primary problem with no underlying cause. The consequences of unregulated hypertension can be costly, if not deadly. Early detection can drastically change the outcome for your pet.
At UVH, we recommend annual blood pressure measurements on all pets seven years of age or older. This allows us to establish a normal baseline blood pressure so changes can be identified early in the process. This is an easy procedure that can be done in the exam room with you present using a doppler or oscillometric blood pressure cuff.
Methods of measuring blood pressure
There are three ways to measure a pet’s blood pressure.
- Oscillometric blood pressure measurement is perhaps the most common method of obtaining a blood pressure reading in general practice. This technique uses a cuff that is applied to the leg or tail of the pet.
- Doppler blood pressure measurement is another common method used in general practice. To achieve an accurate reading, a skilled veterinary professional must correctly place the piezoelectric crystal to pick up the blood pressure.
- Invasive blood pressure measurement involves placing an arterial catheter. This measurement is typically not taken in general practice; it is primarily used while a pet is under anesthesia or in a critical care setting.
Diagnosis and treatment
Once your pet has been diagnosed with hypertension, your veterinarian will plot a course of action to manage the disease. Treatment will depend on whether your pet has any other underlying conditions, and the best management techniques for concurrent diseases will be discussed.
Have you noticed any abnormal changes in your pet that may be attributed to hypertension? Call us at 318-797-5522 to schedule a physical exam.