CONDITION

Systemic Hypertension in Cats

Why this matters now

Systemic hypertension typically develops in older cats, often in association with other conditions. It may be present for some time before obvious signs appear, as cats do not typically show symptoms until target organ damage has occurred. Regular blood pressure monitoring in at-risk cats can help identify hypertension before complications develop.

Untreated hypertension can lead to progressive damage to vulnerable organs, particularly the eyes, kidneys, and heart. The damage may accumulate gradually or manifest suddenly, as in cases of acute retinal detachment causing blindness.

Signals & patterns

Early signals

Changes in behaviour or activity level

Some cats may become more restless or vocalise more frequently, though these changes are often subtle.

Gradual changes in eye appearance

Dilated pupils or subtle changes in how the eyes reflect light may be noticed before obvious visual problems.

Mild disorientation

Occasional moments of seeming confused about surroundings may occur.

Later signals

Sudden blindness

Acute vision loss from retinal detachment or haemorrhage can occur when blood pressure reaches critical levels.

Visible bleeding in the eyes

Haemorrhage within the eye chambers may be visible during examination.

Neurological signs

Seizures, head tilt, or circling may indicate hypertensive damage to the brain.

Click to read about the biological mechanisms

How this is usually investigated

Blood pressure measurement in cats requires technique adapted to their temperament. Underlying conditions that commonly cause secondary hypertension are often evaluated concurrently.

Blood pressure measurement

Purpose: Quantifying systolic and diastolic pressure to confirm hypertension.
Considerations: Multiple readings in a calm environment improve accuracy; stress can elevate readings temporarily.

Fundic examination

Purpose: Examining the retina for evidence of hypertensive damage.
Considerations: Can reveal bleeding, detachment, or other changes indicating eye involvement.

Blood chemistry and thyroid testing

Purpose: Identifying common underlying conditions such as kidney disease or hyperthyroidism.
Considerations: Helps determine whether hypertension is primary or secondary.

Urinalysis

Purpose: Assessing kidney concentrating ability and looking for protein loss.
Considerations: Provides additional information about kidney involvement.

Options & trade-offs

Management focuses on reducing blood pressure to protect target organs, while addressing any underlying conditions contributing to hypertension.

Anti-hypertensive medication

Medications that lower blood pressure through various mechanisms.

Trade-offs: May require dose adjustments and regular monitoring to find effective levels.

Treatment of underlying conditions

Managing hyperthyroidism or kidney disease may help control secondary hypertension.

Trade-offs: Addressing the root cause can be beneficial but may not fully resolve hypertension.

Regular monitoring

Ongoing blood pressure checks to assess treatment response and detect changes.

Trade-offs: Requires periodic visits but helps optimise management.

Environmental stress reduction

Minimising stressors that may contribute to blood pressure elevations.

Trade-offs: Supportive measure rather than primary treatment.

Common misconceptions

Misconception:

"Cats show obvious signs of high blood pressure"

Reality:

Many hypertensive cats appear normal until target organ damage occurs, making routine screening valuable in at-risk cats.

Misconception:

"Blindness from hypertension is always permanent"

Reality:

If detected early and blood pressure is controlled quickly, some vision may be recoverable.

Misconception:

"Blood pressure medication has severe side effects"

Reality:

Most cats tolerate anti-hypertensive medications well, though monitoring helps detect any issues early.

For cats with conditions associated with hypertension, such as chronic kidney disease or hyperthyroidism, awareness of potential eye or behaviour changes can prompt timely evaluation. Understanding what blood pressure monitoring involves may help reduce any concerns about the process.

Last reviewed: 24 April 2026 · Dr Alastair Greenway MRCVS