Hypertension or High Blood Pressure – Causes and Treatment

Last Updated on April 27, 2025

Hypertension, commonly known as high blood pressure, is a widespread health condition affecting millions worldwide. Often called the “Silent Killer,” hypertension quietly damages the body over years before any symptoms develop, increasing the risk of heart disease, stroke, kidney failure, and other serious health issues. Understanding the causes, symptoms, diagnosis, and treatment of hypertension empowers individuals to recognize risks early, seek timely care, and live healthier, longer lives.

Hypertension or high blood pressure is a condition in which the arteries have persistently elevated blood pressure. Hypertension (high blood pressure) is when the pressure in your blood vessels is too high (140/90 mmHg or higher)

What is Hypertension?

Hypertension is defined as a consistent elevation of blood pressure levels above normal thresholds. Blood pressure is the force exerted by blood against the walls of the arteries. When this pressure remains elevated over time, it places strain on the heart, blood vessels, and organs.

According to the American Heart Association (AHA) and World Health Organization (WHO):

• Normal Blood Pressure: Below 120/80 mm Hg
• Elevated Blood Pressure: 120–129 systolic and less than 80 diastolic
• Stage 1 Hypertension: 130–139 systolic or 80–89 diastolic
• Stage 2 Hypertension: 140+ systolic or 90+ diastolic
• Hypertensive Crisis: 180+/120+ mm Hg (requires immediate medical attention)

Untreated, hypertension can lead to damage of various organs such as the retina, kidney, and heart and can rupture the vessels leading to aneurysms or strikes. Thus it becomes very important to recognize and treat the disease at the earliest.

High blood pressure is common but with treatment can be controlled to lead a healthy life.

Hypertension is a silent disease. That means people with high blood pressure do not have any symptoms. Thus, the only way to know about its value is to get it checked.  A sphygmomanometer is an instrument that is used to check blood pressure.

Older age, family history, obesity, physical inactivity, and a high salt diet are frequent risk factors for high BP.

Causes & Types of Hypertension

Hypertension is categorized based on its underlying cause

 Primary (Essential) Hypertension

This type is the most common type of high blood pressure and the cause is not known cause.

• Accounts for about 90–95% of cases
• Develops gradually over years
• No identifiable direct cause
• Influenced by genetics, diet, lifestyle, and aging

Secondary Hypertension

It is the term for high blood pressure with a known cause, such as renal disease, or tumors. It is caused by identifiable underlying conditions, such as

• Kidney diseases (e.g., chronic kidney disease)
• Adrenal gland tumors
• Thyroid disorder
• Obstructive sleep apnea
• Certain medications (e.g., steroids, birth control pills)
• Congenital blood vessel defects

Primary and secondary hypertension may sometimes coexist. Approximately 90-95% of adults with hypertension have primary hypertension and 5-10% of the cases are of secondary hypertension.

Other Types

• Labile hypertension: It is said to be present when the patient is hypertensive at one time and normotensive at another time.
• Malignant hypertension: High blood pressure is associated with complications like papilledema, retinal exudates, and hemorrhage. No absolute BP level can be assigned for this condition. However, these patients usually have BP around 200/140 mmHg.
• Hypertension in Pregnancy: High blood pressure may occur in pregnancy in otherwise normotensive females. Similarly, hypertension may worsen in women with preexisting hypertension. The condition often reverses after the delivery. These patients need to be extra monitored throughout the pregnancy.
  Preeclampsia is the term given to the condition when high blood pressure in pregnancy leads to renal and urine problems, lung edema, and visual problems. Preeclampsia can be dangerous to the mother and baby.

Risk Factors Associated with Hypertension

The exact causes of hypertension are unknown, but several factors are associated. These are

• Smoking
• Obesity or being overweight
• Being obese/overweight as a child
• Diabetes
• Sedentary lifestyle
• High salt intake
• High levels of alcohol consumption
• Stress
• Aging
• Medications such as oral contraceptives
• Family history of hypertension
• Diabetes
• Chronic renal disease
• Adrenal and thyroid tumors
• Sleep Apnoea

Pathophysiology of  Hypertension

In most individuals, hypertension remains asymptomatic for years. They have absolutely no symptoms. Hence high blood pressure is also called silent killer.

However, in severe or prolonged cases, symptoms may include-

• Headaches (especially in hypertensive crises)
• Dizziness
• Blurred vision
• Shortness of breath
• Chest pain
• Nosebleeds
• Fatigue or confusion

These symptoms typically indicate advanced disease or dangerously high blood pressure levels requiring immediate medical evaluation.

A person is labeled hypertensive  which is confirmed after elevated blood pressure is found on at least three separate occasions

Recent activity or stress may result in erroneous readings and regular monitoring may be required before labeling someone as hypertensive.

Complications of Uncontrolled Hypertension

The pathogenesis of essential hypertension and the exact mechanisms underlying essential hypertension have not been established.

Over the period, essential hypertension evolves from occasional to established hypertension to complicated hypertension [with end-organ damage to the vessels, heart, kidneys, retina, and central nervous system].

Persistently elevated blood pressure silently damages the body’s critical systems, leading to

• Heart Disease
  • Left ventricular hypertrophy
  • Heart failure
  • Coronary artery disease (angina, heart attacks)
• Stroke
  • o Ischemic stroke due to arterial blockage
  • Hemorrhagic stroke due to vessel rupture
• Kidney Damage
  • Hypertensive nephropathy
  • End-stage renal disease requiring dialysis
• Vision Loss
  • Hypertensive retinopathy affecting retinal blood vessels
• Cognitive Decline
  • Higher risk of dementia and mild cognitive impairment

Early diagnosis and management are critical to prevent these devastating consequences.

Examination and Diagnosis

Diagnosis is based on blood pressure measurements obtained consistently over time. These could be

• Office BP Measurements: Multiple readings on different days are done to confirm the diagnosis.
• Ambulatory Blood Pressure Monitoring (ABPM): 24-hour monitoring gives a detailed picture of blood pressure fluctuations.
• Home Blood Pressure Monitoring: This is more suitable for improving management accuracy, too.

In cases where high blood pressure is recorded and a diagnosis of hypertension is likely, a  detailed history and examination are done to understand should undergo cardiovascular risk assessment

• Tobacco use
• Increased  LDL
• Obesity
• Age>55 years for men and  65 years for women
• Family history
• Sedentary lifestyle
• Exclusion of secondary causes of hypertension

Patients may have undiagnosed hypertension for years without having had their BP checked. Therefore, a careful history of end-organ damage should be obtained.

Diagnostic Workup

It is done to assess complications or secondary causes

• Blood tests
  •  Hematocrit and CBC
  • kidney function
  • Glucose levels, HbA1c in preexisting diabetics
  • Cholesterol
  • Serum sodium and  potassium
  • Serum Creatinine
  • Lipid profile
• Urinalysis (proteinuria detection)
• Electrocardiogram (ECG)
• Echocardiogram (heart structure and function)
• Fundoscopy (retinal examination)

In addition, if long-standing undiagnosed hypertension is suspected, investigations to look for end-organ disease can be undertaken. These are generally

• Chest x-ray
• Urine microalbumin.
  • Microalbuminuria is an early indicator of diabetic nephropathy
  • Also, a marker for a higher risk of cardiovascular disease
  • All individuals with type I diabetes should be screened for microalbuminuria in case of hypertension

Specific tests for different causes of secondary causes may be done as required.

Treatment of Hypertension

Treatment of hypertension aims to lower the blood pressure to less than 130/90 or even lower.

In patients older than 60 years, some recommendations are fine with  BP less than 140/90

Managing hypertension is a lifelong commitment involving lifestyle changes, medications, and regular monitoring.
The goal is to lower blood pressure to safer levels to prevent long-term complications.

Lifestyle Modifications

Lifestyle interventions are the first line of defense in managing hypertension, especially in the early stages:

•  Dietary Approaches to Stop Hypertension (DASH Diet): High intake of fruits, vegetables, whole grains, and low-fat dairy and reduction in saturated fats and sodium is recommended.Whole grains, fish, poultry, nuts, seeds, and dried beans are recommended. DASH diet has been found to reduce BP by 8-4 mm.
• Sodium Restriction: Limit salt intake to less than 2,300 mg per day, ideally <1500 mg for high-risk individuals.
• Foods rich in potassium: These increase sodium excretion and decrease  sympathetic activity, decrease renin-angiotensin secretion and direct dilatation of renal arteries
• Weight Loss: Even a 5–10% reduction in body weight can significantly lower blood pressure
• Regular Physical Activity: At least 150 minutes of moderate-intensity aerobic exercise per week
• Moderate Alcohol Intake: Limit to ≤2 drinks/day for men and ≤1 drink/day for women
• Smoking Cessation: It is important for reducing cardiovascular risk
• Stress Management: Mindfulness, yoga, and meditation techniques can complement medical therapy

Lifestyle changes can sometimes reduce or eliminate the need for medications in early or mild hypertension.

 

Drug Treatment

When lifestyle modifications alone are insufficient, antihypertensive medications are introduced, often tailored based on individual profiles (age, comorbidities, ethnicity).

Many patients require 2 or more medications for optimal control, often in single-pill combinations.

The treatment involves lifestyle changes and drugs.

Adults with stage 1 hypertension should first be put on a non-drug treatment regimen that includes lifestyle changes and exercise. They should be evaluated every month to see the effect.

Adults with higher initial blood pressure should be put on drug treatment along with lifestyle changes.

Treatment of hypertension is multipronged and complex. Along with blood pressure, the aim is also to reduce the risk of end-organ disease.

The presence of comorbidities further complicates the situation

So additional recommendations do exist.

Common classes of antihypertensive drugs include

• Diuretics: Promote salt and water excretion, reducing blood volume. Many types of diuretics that can be used as antihypertensive drugs like thiazide diuretics (Hydrochlorothiazide, chlorthalidone, potassium-sparing diuretics (Triamterene and amiloride), loop diuretics (Furosemide, torsemide)
• ACE Inhibitors (e.g., enalapril, lisinopril): Block conversion of angiotensin I to angiotensin II, lowering vascular resistance.
• Angiotensin II Receptor Blockers (ARBs) (e.g., losartan, valsartan): Alternative to ACE inhibitors, fewer side effects like cough.
• Calcium Channel Blockers (e.g., amlodipine, diltiazem): Relax and widen blood vessels.
• Beta-blockers (e.g., atenolol, metoprolol): Reduce heart rate and cardiac output; preferred in patients with heart disease.
• Other Agents: Alpha-blockers, central agonists, vasodilators — used selectively.
• Drugs for Lipd Management: Statins may be needed when lipid profile is disturbed.

ACE Inhibitors

Renin released from the kidney acts on circulating angiotensinogen to produce angiotensin I, which is converted to angiotensin II by the converting enzyme. Angiotensin II is a strong constrictor of the vessels. It also stimulates aldosterone, which retains sodium and causes hypertension.

ACE inhibitors act by inhibiting the converting enzyme, preventing the formation of angiotensin II and lowering BP. They also decrease the degradation of bradykinin, a strong dilator of blood vessels [dilatation of vessels lowers blood pressure].

ACE inhibitors also decrease ventricular hypertrophy and arrhythmia due to reperfusion injury. These also decrease microalbuminuria. They are preferred drugs in chronic kidney disease and proteinuria.

ACE Inhibitors are useful in renovascular hypertension. High angiotensin II is however required to maintain adequate filtration pressure behind the stenotic lesion. ACE Inhibitors decrease the perfusion pressure and lead to azotemia. Thus, they are contraindicated in bilateral renal artery stenosis. These drugs are useful in hypertensive diabetics because of their neutral effect on carbohydrate metabolism.

Fosinopril, captopril, Ramipril, enalapril, lisinopril, and quinapril are commonly used drugs.

Surgery

Surgery for hypertension is usually not needed. However, surgery may be considered for lesion removal, like pheochromocytoma or adenoma that produces aldosterone. In cases with renal artery disease, angioplasty is quite successful.

Prognosis

Untreated, most of the people who are diagnosed with hypertension continue to have increasing blood pressure over the years. Untreated hypertension increases the risk of atherosclerotic disease and organ damage within 8-10 years after onset.

Death from ischemic heart disease or stroke increases progressively as blood pressure increases.

A long-term commitment to lifestyle modifications and drug therapy is required.

Prevention of High Blood Pressure

Prevention of Hypertension

Preventing hypertension focuses on maintaining a heart-healthy lifestyle across the lifespan:

• Adopt a low-sodium, high-potassium diet
• Engage in regular aerobic exercise
• Maintain a healthy weight
• Manage stress effectively
• Avoid tobacco and limit alcohol
• Monitor blood pressure regularly, especially if a family history exists
• Treat underlying conditions like diabetes and sleep apnea promptly

Early lifestyle adoption offers the best chance to prevent hypertension.

References

• Whelton PK, Carey RM, Aronow WS, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults. Journal of the American College of Cardiology. 2018;71(19):e127-e248. [Link]
• World Health Organization (WHO). Hypertension. Updated 2023. [Link]
• American Heart Association. Understanding Blood Pressure Readings. [Link]
• Ettehad D, Emdin CA, Kiran A, et al. Blood Pressure Lowering for Prevention of Cardiovascular Disease and Death: A Systematic Review and Meta-analysis. The Lancet. 2016;387(10022):957–967. [Link]
• Oparil S, Acelajado MC, Bakris GL, et al. Hypertension. Nature Reviews Disease Primers. 2018;4(1):18014. [Link]