Much awareness has been generated among people regarding high blood pressure, right to the rural areas, credit going to the non-communicable diseases segment of the Ministry of Health, and the dedicated health personnel, down to the grassroots level.
Blood pressure is the force against which blood flows in the vessels of the body providing blood along with necessary oxygen and nutrients to various parts of the body. Whereas high blood pressure is harmful and causes many complications in the body, low blood pressure is equally bad.
With a mild reduction in blood pressure, one feels giddy, as the blood supply to the brain is slowed. One has a sensation of falling down and darkness before the eyes. With further fall in blood pressure, one feels unable to stand up straight. Severe fall in blood pressure results in shock. If not corrected immediately, this can be fatal due to lack of perfusion to vital parts of the body like the brain, heart, and kidney.
Low blood pressure can be acute at the onset as it occurs due to loss of fluid and electrolytes from the body as it happens in diarrhoea and or vomiting. Trauma with blood loss can also lead to low blood pressure. The extent of the fall in blood pressure depends on the quantity of blood or fluid lost. Sepsis due to severe infection is also a cause of low blood pressure.
Chronic hypotension can occur due to damage to the heart valves as in stenosis of one or more heart valves. Here, due to the narrowing of the heart valve, blood is not pumped out in sufficient quantity to the body parts. Therefore, the blood pressure remains low and one feels giddy.
Heart failure also causes low blood pressure. Severe anaemia impairs perfusion of the heart and results in low blood pressure. Drugs for hypertension can lower blood pressure to even below normal. Therefore, it is important to monitor the blood pressure of an individual who takes antihypertensive medication regularly. If hypotension occurs, the dose of the drug has to be reduced proportionately.
Varicose veins (dilatation of the veins of the lower limb) are yet another condition that leads to low blood pressure. In this, there is insufficient return of blood to the heart due to the dilated veins. This affects the filling of the heart and its output leading to low blood pressure.
Normally with a change in posture, such as from lying to sitting or sitting to standing, blood pressure tends to fall slightly. But in some persons, this fall is aggravated, making them feel giddy, which is known as orthostatic hypotension. Similarly, some individuals develop low blood pressure when they stand in the same position continuously for a long time. This occurs due to the pooling of blood in the lower limbs.
Chronic infections like tuberculosis and HIV are also accompanied at times by low blood pressure.
Acute hypotension necessitates urgent resuscitation to prevent shock. Elevation of the legs is very useful as a First Aid measure to help in improving the return of blood to the heart and, hence, improving blood pressure. Even those with chronic low blood pressure can benefit by lying down for an hour or so with their legs elevated.
Those with varicose veins should use elastic stockings or a crepe bandage to keep the veins compressed. This augments the amount of blood returning to the heart and thus prevents hypotension.
People with orthostatic hypotension should avoid sudden changes in position to avoid low blood pressure. Moving the toes while standing straight for a long time helps in side-stepping hypotension for those who are prone to it.
Correction of the disease process causing low blood pressure cures the low blood pressure also. Eating meals at regular times helps to keep the body healthy and also avoids low blood pressure.
Dr Rachna Pande is a specialist in internal medicine