Blood pressure is the force against which blood flows in the blood vessels of the body providing blood along with necessary oxygen and nutrients to various parts of the body. For good functioning of the body, it is important that the blood pressure remains within normal limits. 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. He has a sensation of falling down and darkness before the eyes. With further fall in blood pressure, he feels unable to stand up straight. Severe fall of 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 and heart.
Low blood pressure can be acute from the onset as it occurs due to loss of fluid and electrolytes from the body as in diarrhea and or vomiting. Trauma with blood loss can also lead to a low blood pressure. The extent of fall in blood pressure depends on the quantity of blood or fluid lost. Sepsis due to severe infection is also a cause for 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 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 heart and result in low blood pressure.
Drugs for hypertension can lower blood pressure to below normal. Therefore it is important to monitor the blood pressure of an individual who takes antihypertensive medication regularly. If hypotension occurs, dose of the drug has to be reduced proportionately.
Varicose veins (dilatation of the veins of the lower limb), is yet another condition which leads to low blood pressure. In this, there is insufficient return of blood to the heart due to the dilated veins. This affects filling of the heart and its output leading to low blood pressure.
Some people’s pressure changes with change in position (orthostatic hypotension). When they stand up from a lying or sitting position, blood pressure tends to fall much. Similarly, some individuals develop low blood pressure when they stand in the same position continuously for long time. This occurs due to 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 the blood pressure. Even those with a chronic low blood pressure can benefit by lying down for an hour or so with legs elevated.
Those having 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 having orthostatic hypotension should avoid sudden change of position to avoid low blood pressure. Moving toes while standing straight for a long time, helps in avoiding hypotension in 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 avoid a low blood pressure.
Dr. Rachna Pande is a specialist in internal medicine at Ruhengeri Hospital