Hypertension also known as high blood pressure (HBP) is a very common condition and an important risk factor for the future development of cardiovascular disease. It can be defined as a disturbance in the circulatory function associated with a persistent elevation of systolic and diastolic blood pressure (BP) above normal or to a level likely to lead to adverse consequences.
The actual level of pressure that can be considered hypertensive is difficult to define; it depends on a number of factors, including the patient’s age, sex, race, and lifestyle. As a working definition, many cardiovascular treatment centres consider that a systolic blood pressure equal to or greater than 140 mm Hg and/or diastolic blood pressure equal to or greater than 90 mm Hg represents hypertension.
Types of hypertension
There are two broad classifications of hypertension based on aetiology
- Primary or essential hypertension and
- Secondary hypertension.
Primary or essential hypertension occurs when the cause is not identifiable. Patients with secondary hypertension have identifiable pathology responsible for their chronically elevated blood pressure (BP).
Other types of hypertension include: white-coat hypertension, resistant hypertension, isolated systolic hypertension, and hypertensive crisis
Causes of high blood pressure
The cause of 90 – 95 % cases of hypertension (essential hypertension) is unknown. The remaining 5 – 10 % of cases is secondary to some other disease conditions. Such causes include:
- chronic kidney disease (CKD)
- renovascular disease
- coarctation of the aorta
- primary aldosteronism
- sleep apnea
- hyperthyroidism and
- Cushing syndrome.
Other cardiovascular risk factors include smoking, alcoholism and some drugs.
Read Also: 16 Drugs That May Increase Blood Pressure
Symptoms of high blood pressure
Hypertension is asymptomatic in most cases and is often, therefore, an incidental finding when patients present with unrelated conditions or may be identified during a cardiovascular risk assessment. Patients with secondary hypertension may have symptoms of the underlying disorder. For example, patients with pheochromocytoma may have
- palpitations, and
- orthostatic hypotension
Patients with Cushing syndrome in addition to classic features (moon face, buffalo hump, and hirsutism) may have
- weight gain
- menstrual irregularities
- recurrent acne
- muscular weakness
In primary aldosteronism, hypokalemic symptoms of muscle cramps and weakness may be present.
How should blood pressure be measured?
- Blood pressure should be measured after the patient has emptied their bladder and has been seated for five minutes with back supported and legs resting on the ground (not crossed).
- Arm used for measurement should rest on a table, at heart-level.
- Use a sphygmomanometer/stethoscope or automated electronic device (preferred) with the correct size arm cuff.
- Take two readings one to two minutes apart, and average the readings (preferred).
- Measure blood pressure in both arms at initial evaluation. Use the higher reading for measurements thereafter.
Understanding blood pressure readings
The table below defines blood pressure readings for adults (age 18 years and older)
|Classification||Systolic blood pressure (mmHg)||Diastolic blood pressure (mmHg)|
|Stage 1 hypertension||140–159||or 90–99|
|Stage 2 hypertension||≥160||or ≥100|
Note: If systolic blood pressure and diastolic blood pressure are in different categories, the overall classification is determined based on the higher of the two blood pressure categories.
Management of hypertension
Hypertension is treated with both lifestyle modifications and pharmacotherapy. The overall goal in the management of hypertension is to reduce associated morbidity and mortality (also called cardiovascular or CV events) by the least intrusive means possible.
Most patients with hypertension including those with diabetes or chronic kidney disease (CKD) under age 60 years have recommended BP goal of less than 140/90 mm Hg. Lower goals may be an option in certain populations. Elderly patients (age > 60 years) have a BP goal of less than 150/90 mm Hg.
The JNC-8 is considered the “gold standard” consensus guidelines for the management of hypertension in the United States.
- Antman, E. and Sabatine, M. (2013). Cardiovascular Therapeutics: A Companion to Braunwald’s Heart Disease (4th ed.). Philadelphia: Saunders.
- James, P., Oparil S., Carter B., Cushman W., Dennison-Himmelfarb C., Handler J. et al. (2014) Evidence-based guidelines for the management of high blood pressure in adults. JAMA, 311(5):507–520.
- Wells, B., DiPiro, J., Schwinghammer, T. and DiPiro, C. (2017). Pharmacotherapy Handbook. (10th ed.). New York: McGraw-Hill Education.
- Whittlesea, C. and Hodson, K. (2019). Clinical Pharmacy and Therapeutics (6th ed.). London: Elsevier Limited.
- Zeind, C. and Carvalho, M. (2018). Applied Therapeutics: The Clinical Use of Drugs (11th ed.). New York: Wolters Kluwer.
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