Hypertension in Cats
Elevated blood pressure – properly called systemic arterial hypertension – is an increase in the systolic or diastolic arterial blood pressure (ABP). Blood pressure has two values: the systolic pressure, which is the high value that develops as the heart contracts and pumps blood, and the diastolic pressure, the low value that occurs as the heart relaxes and fills. For example, 120/80 means a systolic pressure = 120 mm Hg and diastolic pressure = 80 mm Hg. Chronic kidney disease
A systolic ABP consistently exceeding greater than 160 mm Hg in the cat is considered high. Diastolic pressure in cats should not exceed the 100 to 110 mm Hg range provided it is recorded when the pet is relaxed.
Diseases of the endocrine system such as Cushing's disease
Tumors of the adrenal gland, such as pheochromocytoma, which is an adrenocortical tumor causing Cushing's disease or Conn's disease
Central nervous system disorders.
Some cases of hypertension are idiopathic or essential, which means that they have no known cause.
A cat predisposed to kidney disease is more likely to develop hypertension.
Hypertension can affect your cat by causing injury to the following "target" organs including: brain, eyes, heart, kidneys and blood vessels. Hypertension can be suspected by symptoms and clinical examination but can only be diagnosed by repeated measurements of the ABP.
What to Watch For
Symptoms related to underlying diseases (such as endocrine disorders)
Diagnostic tests are needed to recognize hypertension, to help deterine its cause, and exclude other diseases. Tests may include:
Complete medical history and physical examination. Examination should be directed towards the target organs of hypertension. Careful inspection of the eyes, nervous system, heart and kidneys should be completed.
Diagnosis requires measurement of arterial blood pressure. This is generally done using a cuff, similar to that used in children, and a blood pressure device. The stethoscope or auscultatory method used in people cannot be used in cats; instead, the pressure must be determined with either a Doppler flow device or an oscillometric device. Cats can have an "artificially" elevated blood pressure if they become excited. Accordingly, the veterinarian should make repeated measurements of blood pressure before making a diagnosis of hypertension. This may require a brief hospitalization in order to allow repeated measurements in a calm patient.
The underlying cause of hypertension must be identified and this may require blood tests of endocrine function, X-rays or ultrasound examination of abdominal organs.
Treatments for hypertension may include one or more of the following:
The underlying cause of hypertension should be treated. This treatment should be individualized for the patient and the associated problems.
A hypertensive crisis (very high blood pressure with severe clinical signs or evidence of a stroke) should be treated aggressively. This requires hospital treatment with drugs that lower blood pressure. These may include sodium nitroprusside, diuretics, amlodipine or other vasodilator drugs.
Chronic treatment of hypertension in cats usually begins with a calcium channel blocker, amlodipine.
In most cases, a reduction in weight and in dietary sodium will be recommended; however, without drug therapy, these measures will be ineffective in controlling hypertension in cats.
Home Care and Prevention
Administer all treatments as prescribed. Schedule regular follow-up visits to ensure that treatment is successfully controlling the blood pressure. Monitor your cat's activity, alertness, appetite and general quality of life on a regular basis.
Hypertension develops in association with diseases that, at this time, are not preventable.