Systemic hypertension

Systemic hypertension is defined medically as a blood pressure greater than 140/90 mmHg. Recently the American College of Cardiology (ACC) and American Heart Association (AHA) have changed guidelines to indicate that pressures above 130/80 mmHg will be considered hypertension, however the European Society of Cardiology (ESC) and European Society of Hypertension (ESH) continue to define hypertension as 140/90 mm Hg and recommend targeting a patient's blood pressure to less than 130/80 mmHg only in certain conditions ².

Clinical presentation

• usually asymptomatic

• may present with complications (see below)

Accelerated (malignant) hypertension

Defined as a rapid rise in blood pressure to greater than 200/120 mmHg. May occur on a background of pre-existing hypertension or as the first manifestation of hypertension. Malignant hypertension has a high mortality if untreated. Associated with hyperplastic arteriolosclerosis, renal failure, retinal haemorrhages and exudates,papilloedema optic disc swelling, headache, and seizures.

Complications

• accelerated atherosclerosis: especially ischaemic heart disease, stroke, peripheral vascular disease

• left ventricular hypertrophy

• diastolic dysfunction (due to increased afterload)

• aortic dissection (due to medial degeneration)

• intracerebral haemorrhage (due to medial degeneration, Charcot-Bouchard aneurysms)

• lacunar infarcts, deep white matter ischaemia (due to hyaline arteriosclerosis)

• chronic renal impairment (due to hyaline arteriolosclerosis)

• accelerated (malignant) hypertension

Pathology

Aetiology

1. essential hypertension: idiopathic (95%)

2. secondary hypertension: underlying cause identified (5%)

Causes of secondary hypertension:

• renal

  • acute glomerulopathies

  • chronic renal failure

  • renal artery stenosis

  • renin-producing tumour

• Endocrine:

  • adrenal

    • Cushing syndrome

    • primary hyperaldosteronism

    • congenital adrenal hyperplasia

    • phaeochromocytoma

  • other endocrine

    • thyroid dysfunction (hyper- or hypothyroidism)

    • acromegaly

• vascular

  • aortic coarctation

  • vasculitis

• neurogenic

  • psychogenic

  • raised intracranial pressure

  • severe physiological stress, e.g. surgery

• pregnancy

  • pregnancy-induced hypertension (pre-eclampsia)

• drugs

  • steroids

  • adrenergic agents

  • illicit sympathomimetic drugs: cocaine, amphetamines, 3,4-methylenedioxymethamphetamine (MDMA)

Risk factors

• increasing age

• obesity, lack of exercise

• high salt diet

• alcohol, smoking

• stress

• genetic factors, family history

• secondary causes listed above

Treatment and prognosis

• modification of lifestyle factors

• antihypertensive medication

• treat underlying causes

• treat complications