Dr. Jitendra Kumar
Our body needs oxygen and other nutrients for proper functioning. This is achieved through circulation of blood. To achieve this purpose, our heart pumps blood through blood vessels to each and every cell of the body. Because of this pumping activity, blood flows under some pressure.
This is similar to the water supply of our houses. Water flows because of pressure. Normally the pressure should be just adequate to achieve flow to even distant taps but at the same time it should not be that high that pipe gets damaged or there is some leakage. But some times the balance is disturbed and blood pressure increases from a normal acceptable level, this condition is known as hypertension.
During heart contraction (systole) pressure inside the blood vessel becomes maximum. This pressure is known as systolic pressure and is normally 120 mm of mercury. Whereas when heart relaxes (diastole) pressure normally decreases to 80 mm of mercury and is called diastolic pressure. So a normal BP is expressed as 120/80 (Systolic BP/Diastolic BP). Millimeter of mercury (Hg) is a method to measure pressure. It means that pressure of blood is enough to lift a mercury column to the said height.
How to measure your blood pressure?
If we put one tube inside the artery of a patient, through a pressure-measuring device, blood pressure can be directly estimated. This is the method applied in intensive care unit where exact measurement is required in presence of various variables.
A balloon cuff (1) is wrapped around arm. Then through a balloon pump (2) the cuff is inflated to a pressure above the blood pressure. When pressure in the cuff becomes more than that of blood pressure, blood to forearm ceases to flow. Now seeing the mercury column (3), cuff is gradually deflated and blood flow is listened through a stethoscope (4). When pressure in (3) is similar to systolic pressure, blood starts flowing and a sound is heard at (4). After some time sound disappears and this corresponds to the diastolic pressure.
Instead of mercury column, pressure can be measured by a dial manometer also. There are some more simple electronic versions for home use. Ambulatory Blood Pressure monitors have been developed to monitor BP continuously for 12 to 24 hours as patient is sleeping or performing normal activity.
Normal and high blood pressure
It is very difficult to define normal blood pressure. When a group of healthy people will be examined, all of them will have different values. Not only this, a same person may have different value at different times. If you are angry or tense, blood will flow more rapidly and your blood pressure will increase. There is a term called white-collar hypertension. Here blood pressure is high when in a doctor’s clinic but at home blood pressure is normal. Similarly when you are calm and quiet, after a good night sleep, your blood pressure will be lower. These are normal fluctuations. So, to define hypertension BP should be persistently high. And it should have been measured at least twice during two separate examinations after the initial screening.
At normal blood pressure, a person should lead a normal life. This BP is less than 120/80. As per the Seventh US joint national Committee on Prevention, Detection and evaluation of High Blood Pressure (JNC-7), if BP is more than 140/90, it is termed as hypertension. Values in between (120-139/80-89) are pre-hypertension.
In children and pregnant women blood pressure should be lower.
Why does one develop hypertension?
This occurs due to a combination of genetic and environment factors. In more than ninety percent people there is strong family history of hypertension and the cause cannot be pinpointed. This is called essential hypertension and occurs most commonly between the ages of 35 and 55 years. In rest of the patients there may be a specific cause most important being diseases of kidney or hormone. Contraction of main abdominal artery and intake of steroid drugs are among other causes.
Every effort should me made to exclude the presence of underlying offending condition especially when onset of disease is in extremes of age and there is no family history. Plan of treatment may be totally different in these patients.
High salt intake, excessive weight, lack of exercise, mental stress, alcohol intake, crowding are the environmental factors, which increase blood pressure.
Why one should treat hypertension?
Treatment of hypertension is simple. But many people do not take treatment because of ignorance. If left untreated, hypertension can decrease the life span by 10 to 20 years. So cost of this ignorance is heavy.
Hypertension can damage various organs. Because heart has to pump against pressure, its size gradually increases. This further leads to heart attack and cardiac failure. Delicate blood vessels of eyes get damaged due to high pressure leading to disturbance of vision. In brain, damage of vessels can cause formation of blood clots or bleeding causing stroke (paralysis). Sudden rise of BP can cause blindness and coma. 10 % of patients die of kidney failure. Bleeding from various sites such as nose, lungs and menstruation is also common.
Do you have hypertension? What are the symptoms?
Anger and headache are not reliable symptoms. Hypertension may be found in children and sanyasis also. Early morning headache at back of the head may be found in severe hypertension but normally there is no direct correlation between headache and presence or degree of hypertension. So periodic measurement of BP is the only solution.
Other symptoms are- Dizziness, palpitation, easy fatigue, nasal bleeding, blurring of vision, chest pain, breathlessness and fits.
If there is underlying kidney disease then there may be swelling of face and feet, urinary difficulty in form of frequency, difficult voiding, inadequate voiding or decreased urine output. Presence of obesity, rounding of face, muscle weakness, episodic headache, palpitation and perspiration are found if there is underlying hormonal disease.
When high BP is detected for the first time
First, presence of hypertension is confirmed by repeated measurements. Person should be calm and quiet and should have taken some rest before BP measurement. If presence of hypertension is confirmed, then initial evaluation is done to
Determine cause of hypertension
Determine extent of damage especially on heart, kidneys and eyes
Determine presence of other disease, which help in deciding best treatment plan.
A competent doctor should make a thorogh examination at presentation. He should measure BP in both arms in, sitting and standing position. He should make note of all the pulses. Following basic tests must be done- urine examination, kidney function test, hemoglobin level, sodium and potassium level, blood glucose and cholesterol level, eye check up for retina and ECG. Depending on requirement, the doctor may prescribe, chest X-ray, ultrasound abdomen, Doppler study, Nuclear scan, other blood tests including assessment of hormonal diseases.
If there is no family history, if onset is abrupt or if hypertension has started before 35 years of age or after 55 years of age or if BP is difficult to control, there is high probability of underlying disease. In two persons with same level of high BP, the hypertension may be twenty times severe if there are underlying risk factors such as-onset in young age, male sex, persistent diastolic pressure above 115 mm Hg., obesity, smoking, alcoholism, diabetes, high cholesterol and presence of damage to heart, kidney, eyes and brain. These people need more aggressive treatment.
Lifestyle and dietary management
Lifestyle has a major bearing on BP management and all patients, even if they are on medicines, must be encouraged to follow general non-pharmacological methods.
Relief of stress is important. One may have to change his job or his attitude towards job and life. Relaxation techniques and Yoga will be of help.
Smoking and alcohol intake should be minimized.
Weight reduction of 4.4 kg over 6 months is proven to decrease BP by 2.5 mm Hg. Caloric reduction is important.
Exercise as per physical limitation of a person should be encouraged. It helps in Bp control directly and through weight reduction. Exercises like jogging, swimming are better than weight lifting and push-ups.
Role of diet has been proven in several clinical trials. In this regard, important aspects are- calorie, salt, potassium, calcium and fat. Calorie should be restricted to achieve normal weight. Salt restriction is beneficial in lowering BP and it also increases the efficacy of medicines. Some types of patient are particularly salt sensitive such as- kidney patient, elderly and diabetics. Up to 5 gram of common salt per day is desirable. There is no need and use of completely stopping salt. Increased intake of potassium has same effect as that of salt restriction. Potassium is found in fruits and vegetables. But kidney patients should better be avoiding potassium. High calcium intake has also been found to be beneficial for BP control. Fat restriction helps in reducing weight and in limiting damage to blood vessels.
Drugs for high blood pressure
Although lifestyle and diet is definitely important, they may not alone be sufficient. Then a person should not feel disheartened. Requirement of medicine is not a sign of failure of patient’s effort on lifestyle modification. There are many groups of anti-hypertensives from which the best can be chosen for a particular patient. Various groups of medicines with examples are as under-
Diuretics- Furosemide, Hydrochlorothiazide.
ACE-inhibitors- Enalapril, Ramipril, Lisinopril
Angiotensin receptor blockers. (ARB)- Losartan, telmisartan, Irbesartan.
Antiadrenergic- Clonidine, methyldopa, Doxazocin, Prazocin, atenolol, propranolol, labetalol.
Vasodilator- Minoxidil. Hydralazine
Mineralocorticoid receptor antagonist- Spironolactone
Calcium Channel blocker- Amlodipine, Nifedipine, Diltiazem
Treatment has to be individualized. A doctor should start with the best possible medicine as per patient need. For example, diuretics are better for elderly and patients of heart failure but may precipitate gout.. ACE-I and ARB are better for patients of diabetes and of heart attack but ACEI can cause dry cough and foetal damage in pregnancy. Drugs like propranolol reduces anxiety but is harmful in asthma. Drugs like Prazocin may be beneficial in prostate enlargement. Calcium antagonist can better control BP but may cause swelling of feet. Proper choice of medicine along with a change in life style and diet will be able to achieve target BP.
Target blood pressure
Treatment should be started when BP is more than 140/90. If diastolic BP is less than 89 and systolic is more than 160 then again treatment should be started in patients above 65 years of age. Patients who have fluctuating BP and those who are not receiving treatment, should be followed six monthly so that treatment may be started at proper time.
In patients of diabetes and evidence of organ damage, target BP should be 130/85. Lower is better and in some patients especially those with kidney diseases, it is advocated to achieve a target of 120/75. In patients in whom target is not being achieved, there are several possibilities. Prescription might be faulty with inclusion of inadequate and inappropriate drugs. Or patient may not be taking medicines as prescribed. Excessive salt intake makes BP control difficult. Some times BP remains high due to concomitant use of medicines such as steroids, contraceptive pill or even nasal drops for cough and cold.
Hypertension is a very common disease. But many people are not aware about their disease due to absence of clear-cut symptoms. This ignorance can reduce the life span of a person by up to 20 years and can lead to serious complications such as heart failure, kidney failure and brain hemorrhage. So regular BP measurement even in absence of symptom is desirable. When hypertension is detected, one should not jump with BP lowering drug but a complete evaluation of patient is mandatory. Lifestyle and dietary management has an important role in treatment but along with this, medicines may be required. There are numerous medicines from various groups to choose from. An aware and motivated patient with the help of a competent doctor can lead a normal healthy life.
Director of Nephrology and Transplant Medicine at Asian Institute of Medical Sciences (AIMS), Faridabad. He is an expert in many procedures such as CRRT, hemoperfusion, CAPD, and kidney transplant.