THE SILENT KILLER (HYPERTENSION)

What is hypertension

Hypertension is frequently termed "the silent killer" because it typically lacks early symptoms while acting as the primary driver for atherosclerosis and its complications. As an independent risk factor, it predisposes patients to heart failure, stroke, and coronary, renal, and peripheral artery diseases. Consequently, it remains the leading contributor to cardiovascular illness and death in developed nations.

Hypertension is characterised by consistently high blood pressure readings, defined as a top number (systolic) of 130 mm Hg or higher, or a bottom number (diastolic) of 80 mm Hg or higher. High blood pressure raises the likelihood of serious heart problems, including heart failure, strokes, and heart attacks, which can be fatal. Hypertension is both a medical condition and a serious risk factor for other medical conditions. High blood pressure usually has no symptoms, meaning most people only find out they have it by chance during a routine check-up or recording.

Blood pressure varies significantly within an individual; a few, isolated readings are insufficient to determine a true average. Historically, clinical trials have relied on multiple, repeated office visits to diagnose hypertension accurately. This approach addresses the high variability that makes a single reading unreliable.

Grading scheme for hypertension according to the European Society of Cardiology and European Society of Hypertension

• Optimal: SBP less than 120 mm Hg and DBP less than 80 mm Hg

• Normal: SBP 120 to 129 mm Hg and/or DBP 80 to 84 mm Hg

• High normal: SBP 130 to 139 mm Hg and/or DBP 85 to 89 mm Hg

• Grade 1 hypertension: SBP 140 to 159 mm Hg and/or DBP 90 to 99 mm Hg

• Grade 2 hypertension: SBP 160 to 179 mm Hg and/or DBP 100 to 109 mm Hg

• Grade 3 hypertension: SBP greater than or equal to 180 mm Hg and/or DBP greater than or equal to 110 mm Hg

Grading of hypertension for the US according to the American College of Cardiology (ACC)

• Normal: SBP less than 120 and DBP less than 80 mm Hg;

• Elevated: SBP 120 to 129 and DBP less than 80 mm Hg;

• Stage 1 hypertension: SBP 130 to 139 or DBP 80 to 89 mm Hg;

• Stage 2 hypertension: SBP greater than or equal to 140 mm Hg or DBP greater than or equal to 90 mm Hg.

White coat hypertension occurs when clinic readings range between 130/80 and 160/100 mm Hg but drop to 130/80 mm Hg or lower after three months of treatment. Confirming this typically requires home or ambulatory monitoring.

Masked hypertension is the opposite: clinic readings appear nearly normal (120–129 systolic and under 80 diastolic), but out-of-office measurements reveal high blood pressure of 130/80 mm Hg or more.

Primary vs. Secondary hypertension

 Hypertension is categorised into two types based on its cause: primary (or essential) hypertension and secondary hypertension. While essential hypertension (high blood pressure with no identifiable cause) remains the most common diagnosis, approximately 10% of cases are classified as secondary hypertension, where an underlying medical condition is responsible for the elevated readings.

Causes of hypertension

Most high blood pressure cases are idiopathic (of unknown cause), often called essential hypertension. Research has long linked high salt intake to an increased risk of the condition. However, a person's genetic response to salt plays a major role; roughly 50% to 60% of people are salt-sensitive, making them more likely to develop hypertension. 

Management of hypertension

Hypertension treatment is split into lifestyle changes (non-pharmacological) and medication (pharmacological).

• Lifestyle and Non-Pharmacological Care

Regardless of age or risk level, lifestyle improvements are recommended for everyone with high blood pressure. Key focus areas include:

Weight Loss: If obese, losing weight can drop systolic pressure by 5 to 20 mm Hg.

Diet & Habits: Managing salt intake, quitting smoking (to prevent long-term complications), and treating sleep apnoea are essential.

Exercise: Regular activity is a core requirement. Overall, these changes alone can cut cardiovascular events by up to 15%.

• Medication (Pharmacological Therapy)

When drugs are necessary, doctors choose between ACE inhibitors, ARBs, diuretics, calcium channel blockers, or beta-blockers. The specific choice depends on the patient’s age, race, and existing conditions like kidney disease or heart failure.

Complication of uncontrolled hypertension

Large-scale population studies have identified several serious complications linked to uncontrolled hypertension. These include:

Cardiac Events: Coronary heart disease (CHD), heart attacks (MI), and atrial fibrillation.

Vascular & Neurological Issues: Stroke (both ischaemic and haemorrhagic), hypertensive encephalopathy, and aortic aneurysms.

Organ Damage: Peripheral arterial disease and both acute and chronic renal failure.

Mortality: Increased risk of death, typically resulting from stroke or heart and vascular diseases.

References

Iqbal, A. M., & Jamal, S. F. (2023). Essential hypertension. In StatPearls [Internet]. StatPearls Publishing.

Sawicka, K., Szczyrek, M., Jastrzebska, I., Prasal, M., Zwolak, A., & Daniluk, J. (2011). Hypertension–the silent killer. Journal of Pre-Clinical and Clinical Research, 5(2).

Hegde, S., Ahmed, I., & Aeddula, N. (2023). Secondary hypertension. StatPearls.

Gabb G. (2020). What is hypertension?. Australian prescriber, 43(4), 108–109. https://doi.org/10.18773/austprescr.2020.025

Carey, R. M., Moran, A. E., & Whelton, P. K. (2022). Treatment of hypertension: a review. Jama, 328(18), 1849-1861.

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