For good functioning of the body it is important that the blood pressure remains within normal limits.  High blood pressure, is harmful and causes many complications in the body and low blood pressure  is equally harmful.

With a mild reduction in blood pressure, one feels giddy and can occassionally fall down. Severe fall of blood pressure can also result into shock. If not corrected immediately, this can be fatal due to lack of perfusion to vital parts of the body like brain and heart.  

Low blood pressure can be acute 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. Due to  a damaged 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 anemia is  impairs  perfusion of heart and results  in low blood pressure.

Chronic infections like tuberculosis and HIV are also accompanied at times by low blood pressure. 

Drugs for hypertension can  induce a less than normal blood pressure. Therefore, it is important to monitor the blood pressure of an individual who is on antihypertensive drugs.

Similarly diuretics (medicines used to mobilise extra salt and water from the body) can also cause a low blood pressure. 

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  and due pumping of blood by heart. Some people have a tendency for low blood pressure with change in position. When they stand up from a lying or sitting position, blood pressure tends to fall.  

Some individuals develop low blood pressure when they stand in the same position for long time. This occurs due to pooling of blood in the lower limbs.  

Acute   hypotension necessitates urgent resuscitation  to prevent shock. This includes perfusion with fluids containing saline and electrolytes. Elevation of the legs is very useful as a first aid measure to help improve the return of blood to the heart and its pumping ability. 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 prevents hypotension. 

People having  hypotension   should avoid sudden change of position to avoid low blood pressure. Eating meals at regular times is also useful.

Dr Rachna Pande, Specialist Internal medicine, Ruhengeri Hospital