Systemic hypertension is defined medically as a blood pressure greater than 140/90 mmHg. 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, 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

• posterior reversible encephalopathy syndrome (PRES)

Pathology

Aetiology

• essential hypertension: idiopathic (95%)

• secondary hypertension: underlying cause identified (5%)

  • renal

    • acute kidney injury, e.g. acute glomerulonephritis

    • chronic kidney disease

    • renal artery stenosis

    • multiple renal arteries ³

    • juxtaglomerular cell tumour or reninoma (rare)

  • endocrine

    • adrenal: Cushing syndrome, primary hyperaldosteronism, congenital adrenal hyperplasia, phaeochromocytoma

    • other: hyper- or hypothyroidism,

      acromegaly

  • vascular

    • aortic coarctation

    • vasculitis

  • neurogenic

    • dysautonomias, e.g. Guillain-Barré syndrome, anti-NMDA receptor encephalitis

    • raised intracranial pressure

    • severe physiological stress, e.g. surgery, acute stroke

  • pregnancy

    • gestational hypertension

    • pre-eclampsia and eclampsia

  • drugs

    • steroids

    • adrenergic agents

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

    • tacrolimus and ciclosporin

  • other

    • obstructive sleep apnoea

Risk factors

• increasing age

• obesity, lack of exercise

• high salt diet

• alcohol consumption

• smoking

• stress

• genetic factors (usually polygenic) and family history

• secondary causes listed above

Treatment and prognosis

• treat underlying causes

• modification of lifestyle factors

• antihypertensive medication(s)

• treat complications