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Feline high blood pressure
High blood pressure is excessive blood pressure in the vessels. In cats, it is most often the consequence of another disease, in particular chronic kidney failure or hyperthyroidism. It is dangerous because it is silent: the cat does not sh...
What is it?
High blood pressure is excessive blood pressure in the vessels. In cats, it is most often the consequence of another disease, in particular chronic kidney failure or hyperthyroidism.
It is dangerous because it is silent: the cat does not show anything until a fragile organ has been damaged.
The four target organs are the eyes, brain, heart and kidneys. The most common revelation is brutal: an elderly cat who goes blind overnight.
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Related signs — each one links to its page:
Most often: no signs for a long time.
Sudden loss of vision, very dilated pupils, cat bumping into furniture, hesitating to move or refusing to jump.
Bleeding inside the eye, visible as a red spot.
Disorientation, staggering gait, head that seems poorly held, unusual or even aggressive behavior.
Convulsive seizures in severe forms.
Rapid breathing, fatigue on exertion if the heart is affected.
Thirst and increased urine, when kidney disease is associated.
Nosebleeds, rarer.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
In the majority of cases, hypertension accompanies another illness.
Chronic kidney disease is the most common cause in older cats.
Hyperthyroidism comes next: excess thyroid hormones stimulate the heart and blood vessels.
Certain rarer hormonal diseases of the adrenal glands also cause hypertension.
Finally, there are so-called primary cases, where no underlying disease is found.
An important point: in cats, salty food is not the main cause, contrary to a widespread idea from human medicine.
Advanced age: the frequency increases significantly in cats over ten years old.
Known chronic kidney disease.
Hyperthyroidism, diagnosed or not.
Diabetes and other hormonal diseases.
History of tension-related eye injury.
No breed is clearly predisposed: it is age and associated diseases that count.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
Blood pressure is measured in consultation with a cuff placed on a paw or on the tail, without pain for the cat.
The stress of the consultation increases tension: the veterinarian takes several measurements, in a quiet room, after a period of adaptation, and dismisses the first values.
An examination of the fundus of the eye is systematic: it reveals characteristic lesions, sometimes before any sign visible to the owner.
A blood test and urine analysis look for the underlying disease: renal assessment, thyroid hormone dosage, blood sugar.
A heart examination is suggested, particularly if a murmur is heard.
Annual blood pressure screening is recommended in all cats over seven years of age, and at each check-up in cats with kidney or thyroid disease.
Treatment
Treatment always combines two parts: lowering the pressure and treating the disease that causes it.
Medications from the calcium channel blocker family are most often used in cats to lower blood pressure; other families can be associated with them depending on the case.
Treatment is usually continued for life, with pressure checks to adjust support.
At the same time, kidney disease or hyperthyroidism is treated: without this, blood pressure remains difficult to control.
A recent loss of vision can sometimes be partially recovered if the blood pressure is lowered very quickly: this is one of the situations where consulting the same day changes the result.
Never administer human blood pressure medication to your cat: the dosages and molecules cannot be transferred and some are dangerous for him.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
We cannot directly prevent hypertension, but we detect it before it causes damage.
Have blood pressure measured once a year from the age of seven, and more often in a cat being monitored for its kidneys or thyroid.
Respect the checks planned for a cat already treated: the blood pressure changes and the treatment must be adjusted.
Monitor your elderly cat's vision: hesitation on stairs, refusal to jump, abnormally large pupils.
Treat underlying illnesses without letting them take hold.
Possible complications
Retinal detachment and hemorrhages in the eye, often leading to permanent blindness if treatment is delayed.
Vascular accidents in the brain, with convulsions, disorientation or loss of balance.
Thickening of the heart muscle and, ultimately, heart failure.
Worsening of kidney disease: tension damages the kidneys, and damaged kidneys cause tension to rise, in a vicious circle.
When to see a veterinarian
Your cat bumps, hesitates to move or seems to no longer see: consult the same day, vision can sometimes be saved.
His pupils remain very dilated, even in bright light.
You see blood inside his eye.
He staggers, turns in circles, appears disoriented or becomes aggressive for no reason.
He is having a convulsive attack: emergency, consult immediately.
He is elderly, being monitored for his kidneys or his thyroid, and his blood pressure has never been measured.
Prognosis
Hypertension detected before the appearance of lesions is generally well controlled, with daily treatment and regular check-ups.
The prognosis depends mainly on the underlying disease and the condition of the kidneys.
Blindness that has persisted for several days is rarely reversible, but a blind cat adapts remarkably well to stable housing where the furniture is not moved.
Without treatment, damage to the eyes, brain and heart inevitably worsens.
Frequently asked questions
My cat suddenly became blind, is this reversible?
Sometimes, if the blood pressure is lowered urgently and if the retinal detachment is recent. Every hour counts: sudden loss of vision in an elderly cat should be considered an emergency, not an effect of age.
Should we give a salt-free diet?
Significantly reducing salt is not the treatment for hypertension in cats, unlike what is done in humans. The main thing is to treat the cause and use the prescribed medication. Follow your veterinarian's dietary recommendations, especially if the kidneys are affected.
Is the blood pressure taken at the veterinarian reliable if my cat is stressed?
Stress really increases the values: this is why the measurement is done calmly, after a time of adaptation, and over several readings. The veterinarian interprets the whole, never an isolated figure, and also relies on the examination of the fundus of the eye.
Is the treatment lifelong?
Most often yes, because the disease which causes hypertension is itself long-lasting. In certain cases, such as definitively corrected hyperthyroidism, blood pressure can return to normal and treatment can be reduced, always under veterinary supervision.
References
AAFP — American Association of Feline Practitioners
Content reviewed by the TunisieVet editorial team · Updated 09 August 2026
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