High blood pressure is often seen as a part of growing older. The risk of developing essential hypertension, high blood pressure due to unknown causes, increases after the age of 40 years. Most older adults are therefore using chronic high blood pressure medication for decades thereafter. However, what is not often known is that the elderly are at risk of low blood pressure which is known as hypotension. Using high blood pressure medication while suffering with low blood pressure can be dangerous. It is therefore important that every senior is checked regularly for changes in blood pressure, among other cardiovascular disorders that start with age.

Hypotension is the medical term for low blood pressure where the systolic reading is below 90 mmHg and diastolic reading is below 60 mm Hg. Common symptoms of hypotension are dizziness, lethargy and fainting spells. Various medical and surgical conditions lead to symptoms of hypotension like heart problems and hormonal imbalances. In the elderly, side effects of medication is another common reason for hypotension.

Symptoms of Low Blood Pressure

Mild hypotension often does not cause any symptoms. It is only when the blood pressure drops to a point where the different parts of the body are not receiving enough oxygen that the symptoms become evident. This includes :

• Dizziness
• Sudden blackouts
• Poor concentration
• Confusion
• Disorientation
• Blurring of vision
• Cold and clammy limbs
• Nausea
• Fatigue
• Drowsiness
• Irregular pulse rate

Usually hypotension is also associated with symptoms of the underlying cause.

• Left sided chest pain in a heart attack.
• Respiratory distress with swelling of lips and eyes in anaphylactic shock.
• Abdominal pain in case of a ruptured aneurysm of the abdominal aorta.
• Stiffness of neck, sensitivity to light and high fever in meningitis.

Untreated hypotension leads to number of complications like :

• Injuries sustained from falling due to fainting spells. Hypotension is an important cause to consider when investigating falls in the elderly.
• Impairment of blood supply to vital organs which may lead to irreversible damage to the brain and heart tissue. If the hypotension is persistent the brain and heart may be starved off oxygen leading to tissue death as is seen in a stroke and heart attack respectively.

Causes of Hypotension

Normal blood pressure is between 100 to 140 mm of Hg for systolic pressure and 60 to 90 mm of Hg for diastolic blood pressure. With advancing age the normal blood pressure, and specifically the systolic pressure, increases but within a certain limit. Blood pressure is determined by two factors contractility of the heart and resistance by the peripheral arteries. Hypotension arises when the heart does not contract hard enough or if the arteries are wide and therefore providing less resistances. Low blood volume can also cause hypotension.

In seniors, some of the possible causes of hypotension includes :

• Heart diseases like heart valve disease, heart attack (myocardial infarction), arrhythmias and heart failure.
• Hormonal imbalance such as underactive and overactive thyroid gland, adrenal insufficiency in Addison’s disease and low blood glucose (hypoglycemia).
• Dehydration due to loss of fluid and electrolyte loss in severe vomiting, diarrhea and over use of water pills (diuretics).
• Blood loss as in ruptured aneurysm, ruptured spleen or large open wound.
• Severe infections, especially with septicemia.
• Severe allergic reactions – anaphylactic shock.
• Certain medication such as :
  – Diuretics
  – Alpha and beta blockers
  – Antiparkinsonian drugs

Types of Hypotension

There are different types of hypertension which may be related to specific events.

1. Orthostatic (postural) hypotension associated with standing up from a sitting or lying posture.
2. Postprandial hypotension occurring immediately after meals. Mainly elderly people are affected.
3. Vasovagal syncope due to long standing.

Treatment of Low Blood Pressure

The treatment of low blood pressure needs to be directed at the underlying cause. It may involves measures such as :

• Replacement of lost fluid or blood.
• Use of vasopressor agents like dopamine.
• Intake of salt and water.
• Use of compression stockings.

The elderly may experience episodes associated with bradycardia (low heart rate) and if it cannot be effectively managed with medication, surgery for a pacemaker may be warranted.