Chapter: Hypertension
McMaster Section Editor(s): Christine M. Ribic, Karen C.Y. To
Section Editor(s) in Interna Szczeklika: Andrzej Budaj, Wiktoria Leśniak
McMaster Author(s): K. Scott Brimble, Gordon Guyatt
Author(s) in Interna Szczeklika: Andrzej Januszewicz, Aleksander Prejbisz
Additional Information

Note: At the time of publication, important randomized controlled trials and systematic reviews have been published that are almost certainly going to lead to significant changes in the current clinical practice guidelines. The chapters discussing hypertension will be periodically updated as these guidelines become available.


Hypertension is defined as a systolic blood pressure (SBP) ≥140 mm Hg and/or diastolic blood pressure (DBP) ≥90 mm Hg. Clinical classification based on blood pressure values: Table. Definitions and classification of blood…. Target blood pressure values: see Essential Hypertension.

Depending on etiology, hypertension is classified as:

1) Essential hypertension (>90% of cases).

2) Secondary hypertension.

Causes of secondary hypertension:

1) Kidney diseases:

a) Renal parenchymal diseases (see Renal Parenchymal Hypertension).

b) Renovascular diseases (see Renovascular Hypertension).

c) Renin-secreting tumors originating from the renal juxtaglomerular apparatus.

d) Primary sodium retention syndromes: Liddle syndrome, Gordon syndrome.

2) Endocrine diseases: Primary aldosteronism, Cushing syndrome, pheochromocytoma, thyrotoxicosis, hypothyroidism, hyperparathyroidism, carcinoid syndrome, acromegaly.

3) Coarctation of the aorta.

4) Preeclampsia or eclampsia.

5) Acute stress: Burns, alcohol withdrawal syndrome, psychogenic hyperventilation, hypoglycemia, major surgery.

6) Obstructive sleep apnea.

7) Increased intravascular fluid volume.

8) Diseases of the nervous system: Increased intracranial pressure, Guillain-Barré syndrome, quadriplegia, familial dysautonomia.

9) Drugs: Sympathomimetic agents, glucocorticoids, erythropoietin, nonsteroidal anti-inflammatory drugs, calcineurin inhibitors (cyclosporine [INN ciclosporin], tacrolimus), monoamine oxidase inhibitors, oral contraceptives, herbal drugs (eg, ginseng, yohimbine).

10) Toxic substances: Amphetamines, cocaine, heavy metals, alcohol, nicotine.

Causes of isolated systolic hypertension:

1) Increased stiffness of the aorta, most often in the elderly.

2) Conditions causing increased cardiac output: Aortic regurgitation, anemia, thyrotoxicosis, Paget disease, arteriovenous fistulas.


Table. Definitions and classification of blood pressure levels (mm Hg)a


Systolic blood pressure


Diastolic blood pressure













Grade 1 hypertension




Grade 2 hypertension




Grade 3 hypertension




Isolated systolic hypertension




Patients with systolic and diastolic blood pressures falling into different categories are classified into the higher category.

Isolated systolic hypertension should also be classified by grades (1, 2, and 3) based on systolic blood pressure levels.

a Based on office measurements of blood pressure.

Based on: Mancia G, Fagard R, Narkiewicz K, et al. 2013 ESH/ESC guidelines for the management of arterial hypertension: the Task Force for the Management of Arterial Hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC). Eur Heart J. 2013 Jul;34(28):2159-219. doi: 10.1093/eurheartj/eht151.

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