Description

Systemic hypertension (high blood pressure) is recognised with an increasing frequency in vet clinics dealing with cats. It has been estimated that around 20% of elderly cats may suffer from this condition. Whilst it is idiopathic in up to 20% of cases, in most cases it occurs in association with certain medical conditions such as chronic kidney disease, hyperthyroidism, primary hyperaldosteronism (also known as Conn’s disease), hyperadrenocorticism (also known as Cushing’s disease) and phaeochromocytoma. Hypertension is often referred to as a silent killer since clinical signs may not be apparent until the disease is very advanced. There are four ‘target organs’ – body systems that are especially vulnerable to the damaging consequences of high blood pressure – and these are the kidneys, heart, eyes and central nervous system. Patients suffering from systemic hypertension may present with clinical signs associated with target organ damage (TOD) and/or clinical signs associated with any underlying systemic disease or unfortunately, especially in earlier stages, with no clinical signs at all. Therefore, age-related health screening for hypertension is recommended and International Cat Care guidelines suggest that annual blood pressure assessment should be included as a routine in all cats aged 7 years and over. Indirect methods of blood pressure measurement are recommended for conscious cats and unfortunately no methodology is perfect. Stress can also increase blood pressure readings – so called ‘situational hypertension’ – so blood pressure assessments should be done in as calm and cat friendly a manner as possible to reduce the risk of this complicating interpretation of blood pressure readings. Assessment of patients for evidence of TOD can be extremely helpful in confirming systemic hypertension. If a single high blood pressure reading is obtained but there is no evidence of TOD, BP measurements should be repeated again on another day to confirm persistence of high readings before treatment is considered. Conversely, if there is clear evidence of TOD (eg retinal detachment) and a single high reading, this confirms the diagnosis of systemic hypertension and treatment can be started. Where diagnosed, systemic hypertension is typically very straightforward to manage with anti-hypertensive therapies such as amlodipine and/or telmisartan.