Hypertension - Diagnosis
Because hypertension does not produce symptoms it is important to have regular checkups. Taking a person's blood pressure is simple and painless. A doctor or nurse uses an instrument called a sphygmomanometer. A sphygmomanometer (pronounced SFIG-moh-muh-nahm-et-er) consists of a cloth-covered rubber cuff and a pressure valve. The cuff is wrapped around the patient's arm, and air is pumped into the cuff. As the air is slowly released, the doctor or nurse listens through a stethoscope to the sound of the blood rushing through the artery. He or she reads the pressure at which he or she hears distinctive heart sounds (the "lubb" and "dubb" made when a heart beats). These readings provide the patient's systolic and diastolic blood pressures.
Blood exerts pressure. Anyone who has ever cut an artery knows that fact. When that happens, blood gushes out of the artery with surprising force. That fact was first discovered by the English physician William Harvey (1578–1657) in the 1600s.
No one actually tried to measure blood pressure, however, until nearly a century later. Then, the English clergyman and physiologist Stephen Hales devised the first blood pressure measuring device. He cut open the blood vessel in various animals and inserted a metal pipe into the vessel. He then connected the pipe to a long glass tube. Blood was pushed out of the vessel into the glass tube. The blood rose to different levels in the tube for different animals.
It took another century for physicians to find a way to take blood pressure without actually cutting into a blood vessel. In 1876, the German physician Samuel Siegried von Basch (1837–1905) invented the first sphygmo-manometer (pronounced SFIG-moh-muh-nahmet-er). That tongue-twisting name describes the type of blood pressure measuring device used today. It consists of a rubber tube placed around the patient's upper arm. Air is pumped into the tube. Pressure from the air briefly cuts off the flow of blood in the patient's arm.
As the air is released from the tube, the medical worker listens to the patient's arm through a stethoscope. As blood starts flowing in the arm again, the sound produced by systolic pressure can be heard. A few moments later, the sound produced by the diastolic pressure can be heard. The worker notes the amount of pressure observed in a gauge on the arm band at each sound. These two pressures make up the patient's blood pressure reading.
There is no single point at which a person is said to have hypertension. Instead, certain levels of the condition are set depending on the person's blood pressure. These levels are as follows:
- Normal blood pressure: In the range 130/85
- High normal: In the ranges 130–140/85–90
- Mild hypertension: In the ranges 140–160/90–100
- Moderate hypertension: In the ranges 160–180/100–110
- Severe hypertension: In the ranges 180–210/110–120
- Very severe hypertension: Higher than 210/120
Patients with higher-than-normal blood pressure may then be given other tests. These include:
- Medical and family histories. These help a doctor find out if the patient has risk factors in his or her family. If hypertension is common in the family, the patient is likely to be at higher risk for the condition.
- Physical examination. Sometimes other health problems may be discovered during a physical examination that explain the patient's high blood pressure.
- Examination of the blood vessels in the eyes. High blood pressure may cause blood vessels in the eyes to become thick or narrow. Bleeding in the eyes may also be visible.
- Chest X ray. This is used to check for an enlarged heart, other heart disorders, and lung disease.
- Electrocardiograph (ECG). This test measures the electrical activity of the heart. It can determine whether the heart muscle is functioning normally.
- Blood and urine tests. These help determine the general health of the patient.
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