DM3 Pt2-1 Hypertension

Question 1

What is hypertension in cats?

Answer 1

Hypertension in cats is high blood pressure, most commonly found in cats over 10 years of age, often secondary to other diseases such as chronic kidney disease (CKD), hyperthyroidism, or hyperaldosteronism (Conn’s syndrome).

Question 2

What are the primary causes of feline hypertension?

Answer 2

Chronic kidney disease (CKD), hyperthyroidism, and hyperaldosteronism (Conn’s syndrome), which is often due to an adrenal tumor or bilateral adrenal hyperplasia.

Question 3

Which organ systems are affected by hypertension in cats?

Answer 3

Eyes, brain, kidneys, and cardiovascular system are the main target organs affected by hypertension.

Question 4

What are the clinical signs of hypertension in the eyes?

Answer 4

Visual deficits, retinal hemorrhage, retinal detachment, bleeding into the anterior chamber (hyphaema), and blindness.

Question 5

What neurological signs may indicate hypertension in cats?

Answer 5

Altered behavior, ataxia, seizures, dementia, and coma, often due to vascular accidents in the brain.

Question 6

How does hypertension affect the cardiovascular system in cats?

Answer 6

Hypertension can lead to left ventricular hypertrophy, a thickening of the heart’s muscle wall, which can strain the heart.

Question 7

How does hypertension affect the kidneys in cats?

Answer 7

Hypertension can cause glomerular sclerosis and interstitial fibrosis, which may worsen chronic kidney disease (CKD) and cause hypertensive renal damage.

Question 8

What are some subtle signs of hypertension in cats before severe symptoms develop?

Answer 8

Reduced activity, dislike of being handled (especially around the head), and increased vocalization.

Question 9

What are the late-stage signs of hypertension in cats?

Answer 9

Acute onset blindness, often from retinal detachment, is a common late-stage sign.

Question 10

Why is early detection of hypertension in cats important?

Answer 10

Early detection can prevent irreversible damage to target organs such as the eyes, brain, kidneys, and heart. Blood pressure monitoring in older cats is crucial for early detection.

Question 11

What blood pressure changes occur in cats with chronic kidney disease (CKD)?

Answer 11

Hypertension commonly occurs in cats with CKD and may worsen the progression of kidney damage due to increased glomerular pressure.

Question 12

What is Conn’s syndrome, and how does it relate to feline hypertension?

Answer 12

Conn’s syndrome, or hyperaldosteronism, is a condition characterized by excessive production of aldosterone, usually due to an adrenal tumor. It can cause hypertension in cats.

Question 13

What systemic symptoms might a cat with hypertension present?

Answer 13

Polyuria, polydipsia, weight loss, inappetence (often due to CKD), polyphagia (due to hyperthyroidism), or weakness and neck ventroflexion (due to hypokalemia in hyperaldosteronism).

Question 14

What is the recommended way to monitor for hypertension in older cats?

Answer 14

Routine blood pressure monitoring is advised for cats over 10 years of age, along with monitoring for subtle behavioral changes or signs of discomfort.

Question 15

What technique is preferred for measuring blood pressure in conscious cats?

Answer 15

Indirect measurement techniques, such as Doppler ultrasound, are preferred as they do not require sedation or anesthesia and minimize stress for the patient.

Question 16

Why is the oscillometric technique less reliable for measuring blood pressure in cats?

Answer 16

The oscillometric technique is less reliable in conscious cats because it often fails to give a reading, although it can be more accurate in anaesthetised cats. Newer high-definition oscillometry (HDO) technology may offer better accuracy, but more studies are needed to compare it with Doppler and direct measurements.

Question 17

What steps can reduce ‘white coat hypertension’ in cats during blood pressure measurements?

Answer 17

Perform the measurement in a quiet room, away from barking dogs and other noise, and allow the cat 10 minutes to acclimatize to the surroundings before starting the procedure. Having the owner present can also help reduce stress.

Question 18

How should the cat be restrained during the blood pressure measurement?

Answer 18

The cat should be restrained as gently as possible, usually just by gently steadying it while the cuff is placed and readings are taken.

Question 19

What equipment is used for Doppler blood pressure measurement in cats?

Answer 19

Equipment includes a Doppler unit, an inflatable cuff (usually 2.5 cm wide, but cuff width should be 40% of the limb’s circumference), ultrasound coupling gel, and a hand-pump sphygmomanometer.

Question 20

Where should the Doppler probe be placed on the cat for blood pressure measurement?

Answer 20

The probe should be placed over the common digital artery on the palmar surface of the forelimb, between the carpal and metacarpal pads. Ultrasound coupling gel should be applied to the skin and the probe to ensure a good signal.

Question 21

How do you determine systolic blood pressure (SBP) using Doppler?

Answer 21

Inflate the cuff to 20-30 mmHg above the point where the sound of blood flow is obliterated. Then, slowly deflate the cuff and record the SBP as the pressure at which blood flow is first detected consistently again.

Question 22

How many blood pressure readings should be taken to ensure accuracy?

Answer 22

At least five readings should be taken over 2-3 minutes, and the average of these readings should be recorded as the SBP.

Question 23

What should be done if the first few readings are unusually high?

Answer 23

If the first 2-3 readings show a sharp drop (20-30 mmHg) in SBP due to stress, those initial readings should be discarded.

Question 24

Why is Doppler preferred over oscillometric methods for measuring blood pressure in conscious cats?

Answer 24

Doppler is more reliable in conscious cats as it provides more consistent readings, whereas oscillometric methods often fail or are inaccurate in conscious cats.

Question 25

What role does the use of headphones play in blood pressure measurement with Doppler?

Answer 25

Wearing headphones can prevent the cat from being disturbed by the sound of the Doppler unit, which may reduce stress during the measurement.

Question 26

What precautions should be taken while using the Doppler probe?

Answer 26

The Doppler probe should be held gently against the skin, avoiding excessive pressure that could impede blood flow.

Question 27

What is the normal systolic blood pressure in cats?

Answer 27

Systolic pressure consistently less than 150 mmHg and diastolic less than 95 mmHg.

Question 28

What is borderline hypertension in cats?

Answer 28

Systolic pressure consistently between 150-159 mmHg and diastolic between 95-99 mmHg.

Question 29

What is the systolic range for hypertension in cats?

Answer 29

Systolic pressure consistently between 160-179 mmHg and diastolic between 100-119 mmHg.

Question 30

What is considered severe hypertension in cats?

Answer 30

Systolic pressure consistently greater than 180 mmHg and diastolic greater than 120 mmHg.

Question 31

Why is systolic blood pressure used for clinical assessment in cats?

Answer 31

Measurement of systolic blood pressure (SBP) is adequate for clinical assessment because isolated diastolic hypertension is rare in cats.

Question 32

What subtle changes in the retina may be seen in early cases of hypertension in cats?

Answer 32

Early changes may include focal areas of perivascular retinal oedema.

Question 33

What dramatic changes in the retina can be seen in severe hypertensive cases?

Answer 33

More dramatic changes include serous or haemorrhagic retinal detachment and intraocular haemorrhage.

Question 34

What are the long-term effects of untreated hypertension on the retina in cats?

Answer 34

Long-term untreated hypertension can lead to retinal degeneration, recognized by areas of hyperreflectivity in the retina.

Question 35

What tool is used to examine the retina in hypertensive cats?

Answer 35

Indirect ophthalmoscopy is used to examine the retina. A pen torch can also be used effectively for this examination.

Question 36

Why is ophthalmic examination useful in hypertensive cats?

Answer 36

Ophthalmic examination can reveal early retinal changes and is useful in diagnosing retinal detachment, oedema, and intraocular haemorrhage.

Question 37

What are the initial diagnostic tests to exclude underlying causes of hypertension in cats?

Answer 37

Haematology, biochemistry (including urea/creatinine and electrolytes), urinalysis (including specific gravity), total T4 measurement, and possibly an aldosterone assay.

Question 38

What additional investigations may be required based on clinical findings?

Answer 38

Abdominal ultrasound (e.g., for adrenal masses), echocardiography, and investigation of other clinical signs based on the patient’s condition.

Question 39

What is the primary treatment for hypertension in cats?

Answer 39

Amlodipine besylate, a calcium channel blocker, is the primary treatment for hypertension in cats. It is dosed at 0.625-1.25 mg per cat once daily, increasing to twice daily if needed.

Question 40

What other treatment can be used in combination with amlodipine for refractory cases?

Answer 40

ACE inhibitors such as benazepril may be used in combination with amlodipine for refractory cases.

Question 41

How soon should a response to amlodipine therapy be seen in cats with hypertension?

Answer 41

Blood pressure should drop into the normal range (130-170 mmHg) within 7–10 days of starting therapy.

Question 42

How frequently should blood pressure be monitored in hypertensive cats after starting treatment?

Answer 42

Initially, monitor SBP and ocular abnormalities closely during the first two weeks of treatment. After stabilization, assess the patient every 1–2 months, eventually reducing the frequency to once every 6 months in very stable patients.

Question 43

What is important to monitor in cats with renal disease before starting anti-hypertensive therapy?

Answer 43

Blood urea and creatinine levels should be monitored before starting anti-hypertensive therapy and during the initial treatment period, especially in cats with pre-existing renal disease.

Question 44

Why is monitoring renal function important during hypertension treatment?

Answer 44

Anti-hypertensive agents can cause systemic hypotension, reducing renal blood flow and glomerular filtration rate, which may worsen renal function, especially in cats with pre-existing renal disease. However, anti-hypertensive agents are beneficial in hypertensive cats with renal disease, and renal function deterioration is uncommon.