The Other Side of Blood Pressure: Hypotension

You have probably heard and read a lot about high blood pressure and the health risks associated to this condition. However, low blood pressure is as dangerous as its counterpart. The pressure of blood in the arteries may vary above or below what is considered a normal blood pressure 120/80 mmHg.

Low blood pressure, which the medical term is Hypotension, is subnormal arterial blood pressure that often occurs when systolic blood pressure drops down less than or equal to 90 mmHg. Abnormally low blood pressure is often seen in shock, but this condition does not lead to shock.

Postural hypotension and orthostatic hypotension are the common causes of low blood pressure, occurring due to changes in body position, whether when an individual moves to a vertical position, or lies down suddenly. By means of a tilt-table, testing these causes can be confirmed.

However, as a medical condition is more likely to be the result of reduced blood volume, usually referred as hypovolemi, that most of the times is induced by excessive use of diuretics. Hypovolemia is also caused by vasodilator therapy with calcium channel blockers, nitrate preparations and/or ACE inhibitors

Low blood pressure is also seen as a side effect of certain forms of anesthesia, including curare, in which event hypotension is typically treated by the anesthesiologist. Another unknown form of hypotension may occur to any individual 30 to 75 minutes after eating: the "Postprandial hypotension" in which the cause is not understood.

Orthostatic hypotension or postural hypotension is the sudden fall in blood pressure returning a measure of 20/10 mmHg. Symptoms occurring after suddenly standing in an upright position, and may include headache, dizziness, blurred or dimmed vision, light-headedness, and syncope.

In medicine and physiology, hypovolemia refers to the state of decreased blood volume, associated to the decrease in volume of blood plasma, contributing to low blood pressure stages. Some causes of hypovolemia include bleeding, dehydration and severe burns. Severe hypovolemia leads to hypovolemic shock.

In general terms, low blood pressure is usually accompanied by signs and symptoms such as headache, chest pain, irregular heartbeat, shortness of breath, dizziness, light-headedness, stiff neck, severe upper back pain, cough with phlegm, foul-smelling urine and burning with urination.

In severe cases hypotension presents fever higher than 38.3° C (101° F), seizures, inability to drink or eat, prolonged diarrhea or vomiting, adverse effect of medications, acute, life-threatening allergic reaction and loss of consciousness. The low flow of blood through the arteries and veins also avoid the delivery of enough oxygen and nutrients to vital organs such as the brain, heart, and kidney.