Low Blood Pressure, or hypotension, occurs when blood pressure during and after each heart beat is much lower than usual. This means the heart, brain, and other parts of the body do not get enough blood.
Low Blood Pressure Cause
Low blood pressure can develop during pregnancy, and as a side effect of taking certain medications, including beta blockers, tricyclic antidepressants, medications used to treatParkinson’s disease, and alcohol. Combining other drugs with medications prescribed for high blood pressure or blood pressure medications themselves can sometimes cause abnormally low blood pressure.
In addition, thyroid problems, low blood sugar, dehydration, and, sometimes, diabetescan influence blood pressure. In rare cases, low blood pressure may suggest a serious medical problem, such as a cardiac, endocrine, or neurological disorder.
As we get older, the reflexes in our circulation that keep pressure constant get slower and blood pressure can drop suddenly when you stand up; this is called postural or orthostatic hypotension. This is a common concern, often compounded by prolonged bed rest, pregnancy, dehydration, diabetes, heart problems or the effects of certain drugs. An estimated 20 percent of adults over the age of 65 develop this problem. For older people, blood pressure may also drop immediately after eating.
Low blood pressure is commonly caused by drugs such as:
- Medications used for surgery
- Anti-anxiety medications
- Heart medicines, including those used to treat high blood pressure and coronary Heart disease
- Diuretics
- Certain antidepressants
- Pain killers
- Alcohol
Other causes of low blood pressure include:
- Dehydration
- Heart failure
- Heart attack
- Changes in heart rhythm (arrhythmias)
- Fainting
- Anaphylaxis (a life-threatening allergic response)
- Shock (from severe infection, stroke, anaphylaxis, major trauma, or heart attack)
- Advanced diabetes
Conditions that can cause low blood pressure
Some medical conditions can cause low blood pressure. These include:
- pregnancy. Because a woman’s circulatory system expands rapidly during pregnancy, blood pressure is likely to drop. During the first 24 weeks of pregnancy, systolic pressure commonly drops by five to 10 mm Hg and diastolic pressure by as much as 10 to 15 mm Hg. This is normal, and blood pressure usually returns to your pre-pregnancy level after you’ve given birth.
- Heart problems. Some heart conditions that can lead to low blood pressure include extremely low heart rate (bradycardia), heart valve problems, heart attack and heart failure. These conditions may cause low blood pressure because they prevent your body from being able to circulate enough blood.
- Endocrine problems. An underactive thyroid (hypothyroidism) or overactive thyroid (hyperthyroidism) can cause low blood pressure. In addition, other conditions, such as adrenal insufficiency (Addison’s disease), low blood sugar (hypoglycemia) and, in some cases, diabetes, can trigger low blood pressure.
- Dehydration. When you become dehydrated, your body loses more water than it takes in. Even mild dehydration can cause weakness, dizziness and fatigue. Fever, vomiting, severe diarrhea, overuse of diuretics and strenuous exercise can all lead to dehydration.Far more serious is hypovolemic shock, a life-threatening complication of dehydration. It occurs when low blood volume causes a sudden drop in blood pressure and a reduction in the amount of oxygen reaching your tissues. If untreated, severe hypovolemic shock can cause death within a few minutes or hours.
- Blood loss. Losing a lot of blood from a major injury or internal bleeding reduces the amount of blood in your body, leading to a severe drop in blood pressure.
- Severe infection (septicemia). Septicemia can happen when an infection in the body enters the bloodstream. These conditions can lead to a life-threatening drop in blood pressure called septic shock.
- Severe allergic reaction (anaphylaxis). Anaphylaxis is a severe and potentially life-threatening allergic reaction. Common triggers of anaphylaxis include Foods, certain medications, insect venoms and latex. Anaphylaxis can cause breathing problems, hives, itching, a swollen throat and a drop in blood pressure.
- Lack of nutrients in your diet. A lack of the vitamins B-12 and folate can cause anemia, a condition in which your body doesn’t produce enough red blood cells, causing low blood pressure.
Low Blood Pressure Symptoms
For some people, low blood pressure can signal an underlying problem, especially when it drops suddenly or is accompanied by signs and symptoms such as:
- Dizziness or lightheadedness
- Fainting (syncope)
- Lack of concentration
- Blurred vision
- Nausea
- Cold, clammy, pale skin
- Rapid, shallow breathing
- Fatigue
- Depression
- Thirst
Tests For Low Blood Pressure
The following tests may be done:
- Complete blood count ( CBC) and other blood tests, including blood differential
- Blood cultures to check for infection
- ECG
- Urinalysis
- X-ray of the abdomen
- X-ray of the chest