Feline systemic hypertension: Diagnosis and management

Abstract

Practical relevance: the clinical importance of feline hypertension has been recognised for many years and most feline practitioners are quite familiar with this syndrome. Once systemic hypertension is identified, long-term management of the patient is needed to avoid catastrophic (eg, blindness due to retinal detachment) or subtle (eg, accelerated renal damage) target organ damage.

Patient group: feline systemic hypertension is most commonly a complication of renal disease and hyperthyroidism, both diseases of older feline patients. By 15 years of age, the probability of having at least one of these two diseases is high. As well cared for cats are living longer, optimal long-term management of feline hypertension in patients with concurrent diseases is an issue of clinical importance.

Clinical challenges: obtaining accurate blood pressure measurements in patients that are anxious, fractious or just plain uncooperative remains a significant issue in feline medicine, as does confident analysis of results from these patients.

Diagnostics: careful measurement of systolic blood pressure using Doppler or oscillometric techniques in conjunction with evaluation for evidence of hypertensive choroidopathy (funduscopic examination) and hypertensive cardiac changes (thoracic auscultation) are essential to the diagnosis of systemic hypertension in cats. Other diagnostic techniques, including evaluation of renal and thyroid function, are needed to detect the underlying disease condition.

Evidence base: numerous well-designed clinical studies have greatly advanced our understanding of the most appropriate methods of diagnosis and therapy of feline hypertension.

Blood pressure measurement using Doppler sphygmomanometry. An appropriate-sized cuff is positioned at mid-radius level on the cat. Note the gentle restraint, comfortable position of the patient and positioning of the limb such that the cuff is at the level of the cat's heart

Blood pressure measurement using an oscillometric technique. An appropriate-sized cuff is positioned at the tailhead of the cat and, without requiring any patient manipulation, is approximately at the level of the heart. Note the comfortable position, and minimal restraint, of the patient

Measurement of the tailhead circumference in a cat to determine the appropriate size of tail cuff for oscillometric blood pressure measurement

Diagnostic algorithm for senior cats

Hypertensive cat with ocular TOD including bilateral retinal detachment. The patient is also exhibiting photophobia (squinting and avoidance of bright light)

Diagnostic algorithm for cats with evidence of target organ damage

Pickle, a 15-year-old female spayed domestic shorthair cat, was presented for emergency examination with an increased respiratory rate of 2 days’ duration. She had no significant medical history prior to this presentation.

Diffuse elevation of the retina around the optic nerve is causing an ‘unfocused’ appearance, although retinal vessels remain in focus. Punctate intraretinal haemorrhages are noted in the upper right portion of the image. Courtesy of Dr Ellison Bentley

Left lateral radiograph of Pickle, showing generalised cardiomegaly and moderate pleural effusion