Hypertension – Symptoms, Causes, Types, Complications & Prevention

Hypertension meaning 

Hypertension is the persistent increase of blood pressure on the wall of the blood vessels, which is the result of two forces: systole and diastole. 

• Systolic pressure: The pressure created by pumping blood from the heart into the arteries. 
• Diastolic pressure: The pressure created by the resting of the heart between heartbeats.

These two forces are represented during the measurement of blood pressure.

The pressure of blood is ever exerted on the walls of the blood vessels, but only when it shows a constant increase; it is called hypertension (high blood pressure). The blood pressure is exerted in arteries in the first place due to the pumping of blood by the heart. 

Pumping of blood to all the tissues and organs of the body is necessary for their survival and proper functioning as oxygen is being delivered by the blood. 

Hypertension definition

In accordance with most major guidelines, it is recommended that a person can be deemed hypertensive if the systolic blood pressure (SBP) in the office or clinic is ≥140 mm Hg and/or the diastolic blood pressure (DBP) is ≥90 mm Hg after repeated examinations.

The normal blood pressure is 

• Systolic blood pressure <130 mmHg 
• Diastolic blood pressure <85 mmHg
  

Hypertension prevalence​

Prevalence of hypertension in the world 

Despite the stable global age-standardised prevalence, it was found that hypertension doubled between 1990-2019 in people aged 30–79 years, i.e.:

• While 33.1 crore women suffered from hypertension in 1990, the number rose to 62.6 crore in 2019.
• And 31.7 crore men suffered from hypertension in 1990; the number rose to 65.2 crore in 2019.

While a previous diagnosis of hypertension was reported in 59% of women and 49% of men in 2019 worldwide, 47% of women and 38% of men were treated for it. Nevertheless, the control rates were 23% for women and 18% for men. Read the full report

Prevalence of hypertension in India

An estimated 22 crores are suffering from hypertension, although only approximately 12% of them have it under control. According to the National Family Health Survey (NFHS-5) 2019–2020 report, the prevalence of hypertension in: 

• Men is 24% which was a 5% increase since the previous report (2015–16).
• Women is 21% which was a 4% increase since the previous report (2015–16). 

Currently, the medical body, India Hypertension Control Initiative (IHCI) has been working on the target of reducing at least 25% in the prevalence of hypertension by the year 2025. Read the full report

Etiology of hypertension | Causes of hypertension

Based on the etiology of hypertension, the two causes of hypertension are - essential or primary hypertension and secondary hypertension.

• Causes of essential or primary hypertension: In most patients (about 90% of people), hypertension results from an unknown pathologic etiology (cause) of essential or primary hypertension. This form of hypertension cannot be cured, but it can be controlled. Genetic factors may play an important role in the development of essential hypertension.
• Causes of secondary hypertension: If hypertension occurs a specific cause, it is called secondary hypertension, which is seen in a small percentage of patients. There are many potential causes of secondary hypertension (comorbid diseases or drugs), such as: 

The development of secondary hypertension as a result of diseases or drugs has complex pathways. The most common of them have been simplified and explained below:

• Chronic kidney disease (CKD) - Hypertension, particularly resistant hypertension, can not only occur as a result of CKD, but it is also an important risk factor for CKD progression. At some point, it becomes difficult to determine which disease process precedes the other, as both diseases share similar risk factors. 

• Coarctation of the Aorta - The aorta is the body's biggest artery transporting oxygen-rich blood from the heart to the body. Coarctation of the aorta is the narrowing of the aorta, stimulating the heart to pump more vigorously to transport blood through the aorta. The narrowed artery and increased pumping of the heart develops hypertension eventually. 

• Obstructive sleep apnoea (OSA) - A sleep disorder with episodes of complete/partial collapse of the airway with a decrease in oxygen saturation or arousal from sleep. This disturbance results in fragmented, nonrestorative sleep, which is prohypertensive. 

• Amphetamines – These stimulants of the central nervous system (CNS) accelerate physical and mental processes, momentarily increasing alertness and boosting mood, used to treat narcolepsy, attention deficit hyperactivity disorder (ADHD) etc. Amphetamines increase the heart rate and decrease muscle contraction force. Blood pressure is the result of an increase in cardiac contractility. 

• Corticosteroids (also called steroids) – These are the drugs given to reduce inflammation and suppress the agitated immune system. Humans can produce steroids from adrenal glands, but in the case of insufficiency, they can be supplemented externally. Glucocorticoids have been implicated in the controlling of blood pressure through a wide variety of extrarenal tissues, such as the vascular smooth muscle, vascular endothelium, CNS, and adipose tissue. 

• Decongestants - These drugs can temporarily relieve stuffy noses (nasal congestion), colds, flu, hay fever, catarrh, and sinusitis. They work by opening the airway and constricting nasal blood vessels. As they might worsen hypertension, patients suffering from hypertension should be cautious when taking these drugs. 

Sign and symptoms of hypertension

While the majority of the people suffering from hypertension do not feel any hypertension symptoms (asymptomatic). Hypertension headache is one of the prominent symptoms which can be seen in symptomatic patients with high blood pressure (usually 180/120 mm Hg or higher). The other presenting symptoms include:

• Dizziness
• Vomiting
• Nausea
• Chest pain
• Confusion
• Anxiety
• Nosebleeds
• Buzzing in the ears
• Difficulty breathing
• Abnormal heart rhythm
• Blurred vision or other vision changes

Risk factors of hypertension 

High blood pressure risk factors increase with age in both men and women. Although men demonstrate higher blood pressure at younger ages when compared with women, by the age of 60, women tend to have higher blood pressure than men.

Similar to age and gender, the various modifiable risk factors for hypertension include: 

• High sodium intake
• Low potassium intake
• Alcohol consumption
• Obesity
• Lack of physical activity
• Unhealthy diet 

High sodium intake: While the recommended amount of sodium intake was 2,300 mg or less per day, the global sodium intake reported in 2010 was 3,950 mg per day – a considerably higher intake than the recommended amounts. Particularly, the East Asian countries consumed the most (>4,200 mg per day). Research from several meta-analyses demonstrated the reduction of sodium significantly decreases blood pressure in hypertensive individuals.

Low potassium intake:  Observational epidemiological research has found an inverse relationship between blood pressure levels and dietary potassium consumption. Potassium supplementation can reduce systolic pressure by 3.11 mmHg and diastolic pressure by 1.97 mmHg.

Alcoholism:  Alcohol consumption globally increased from 5.9 L per capita (1990) to 6.5 L (2017). While light to moderate drinkers had a lower risk of hypertension than non-drinkers, heavy drinkers had a greater risk than both light to moderate drinkers and non-drinkers. Alcoholics drinking six or more drinks per day showed a 5.50 mmHg lower systolic pressure and a 3.97 mmHg lower diastolic pressure with just a 50% reduction in alcohol intake.

Lack of physical activity:  At least 150 min or 75 min of vigorous-intensity or moderate intensity per week is the recommended physical activity. Globally, the age-adjusted prevalence of insufficient physical activity is higher in women (31.7%), than in men (23.4%). Insufficient physical activity is greater in urbanised populations. Even moderate physical exercise (such as walking to work) can reduce the risk of incident hypertension.

Overweight and obesity:  From 1975 to 2014, the global age-standardised obesity prevalence in men increased from 3.2% to 10.8% and from 6.4% to 14.9% in women. A 5.1 kg body weight decrease (through calorie restriction, increased activity etc.) can reduce systolic pressure by 4.44 mmHg and diastolic pressure by 3.57 mmHg.

Unhealthy diet:  There are several macro and micronutrients, including dietary fibre, protein, and fat, are associated with blood pressure maintenance. Seven unhealthy items which are cause hypertension are saturated fat, trans fat, unprocessed red meats, sugar-sweetened beverages, processed meats, dietary cholesterol, and sodium. Mediterranean and vegetarian diets are associated with blood pressure reduction.

Other potential risk factors:  The other risk factors which could develop hypertension include cigarette smoking, air pollution, psychological stress, sleep difficulties, and noise exposure. 

Types of hypertension

Depending on the effect of hypertension over the body or limited to an area, hypertension types can be divided into systemic hypertension and localised hypertension.

There are various types of systemic hypertension are: 

• Essential or primary hypertension: This type of hypertension can be attributed to an unknown cause and is seen in most patients (about 90% of people). Essentially genetics play an important role in it. 

• Secondary hypertension: This type of hypertension occurs due to various specific causes. 

• Malignant hypertension: Severe high blood pressure causing target organ damage.

• Isolated systolic hypertension: Hypertension is commonly seen in the elderly due to elasticity loss in major arteries.

• Resistant hypertension: Persistence of high blood pressure despite taking more than three different antihypertensive agents. 

• Refractory hypertension: Persistence of high blood pressure despite taking more than five different antihypertensive agents. 

• Postpartum hypertension: Blood pressure peaks between three and six days, even in mothers with normal blood pressure after giving birth. 

• Preeclampsia (gestational hypertension): During pregnancy, it is common to experience hypertension called gestational hypertension or preeclampsia which increases the risk of maternal death and foetal defects. 

• White coat hypertension: In this case, hypertension occurs during hospital visits but is normal elsewhere. In India, surprisingly, younger populations demonstrate a higher risk of white coat hypertension compared with the elderly. 

• Masked hypertension: Blood pressure seems normal in the doctor’s office, but high blood pressure is seen when out of the office. 

• Labile hypertension: Frequent fluctuations (between normal and high) in blood pressure. 

• Nocturnal hypertension: Hypertension is seen only during the nighttime (BP ≥120/70 mmHg). It can cause subclinical organ damage. 

• Permissive hypertension: Treatment-induced technique (by reducing hypertensive medication) in maintaining higher blood pressure after a stroke. It promotes faster recovery.

• Asthma hypertension: Hypertension associated with asthma. This was confirmed through years of research but with unknown causes. 

• Carcinoid hypertension: Cancer releases chemicals in the blood, which brings various complications. Hypertension is one of them. 

• Pseudohypertension: A falsely elevated blood pressure measurement seen in the elderly, diabetics, or in those with chronic kidney disease caused by rigid, calcified brachial arteries. 

There are various types of local hypertension are:

• Portal hypertension: Elevated blood pressure in the liver (portal vein) and capillaries branching from the same.

• Pulmonary hypertension: Elevated blood pressure exerted against the blood vessels going from the heart to the lungs.

• Idiopathic intracranial hypertension: Increased pressure around the brain (due to unknown reasons) causing vision changes and headaches. 

• Epididymal hypertension: During the arousal state, blood is built up in the testicles, causing pain and rigid erection. This condition is also called blue balls. 

• Ocular hypertension: Increased intraocular pressure (high pressure in aqueous humour in the eyes) due to failure in fluid drainage. 

• Postural hypertension: Hypertension during an upright posture, also called orthostatic hypertension. 

• Renovascular hypertension: Compromised blood flow to the kidneys, leading to renovascular hypertension. This serious condition could lead to heart attack, stroke, and even death. 

• Venous hypertension: Elevated blood pressure in veins, especially in the lower extremities (legs), due to weakened vein valves. 

• Paediatric hypertension: Elevated blood pressure of children and adolescents when the measurement is in between the 90th and 95th percentiles for height, gender, and age, and as having hypertension when their blood pressure is greater than or equal to the 95th percentile. 

• Reactive pulmonary hypertension: During hypoxia (low level of oxygen), blood pressure in pulmonary vasculature is seen, which can be treated by medicines and/or by increasing the alveolar oxygen tension. 

Frequently Asked Questions (FAQs) on Hypertension

Department of General Medicine