Low Blood Pressure (Hypotension) – Causes, Symptoms, Diagnosis, & Treatment
What is low blood pressure?
Low blood pressure refers to a condition of blood pressure that is lower than normal. It is referred to as hypotension in medical terms. Normal blood pressure is between90-120 mmHg diastolic and 60-90 mmHg systolic. Low blood pressure occurs when the pressure is less than 90 mmHg systolic and 60 mmHg diastolic. When this condition occurs, the heart, brain, and other parts of the body do not get enough blood.
What causes low blood pressure?
There are different types and causes of low blood pressure. Blood pressure varies from one person to another.
Sudden loss of blood (shock), severe infection, heart attack, or severe allergic reaction (anaphylaxis) can cause severe hypotension.
A sudden change in body position causes orthostatic hypotension. This may occur when you shift from lying down to standing. This type of low blood pressure usually lasts only a few seconds or minutes. If this type of hypotension occurs after eating, it is called postprandial orthostatic hypotension. This type of hypotension mostly affects older adults, those with high blood pressure, and people with Parkinson disease.
Neurally mediated hypotension (NMH) is caused when a person has been in a standing position for a long time. This type of hypotension most often affects young adults and children. Children usually outgrow this type of hypotension.
Some of the following medicines and substances can cause low blood pressure:
- Anti-anxiety medicines
- Certain antidepressants
- Heart medicines, including those used to treat high blood pressure and coronary heart disease
- Medicines used for surgery
The following are the other causes of low blood pressure:
- Arrhythmias (changes in heart rhythm)
- Dehydration (inadequate intake of fluids)
- Heart failure
- Nerve damage from diabetes
What are the symptoms of low blood pressure?
The following are the common symptoms of low blood pressure:
- Nausea or vomiting
- Blurred vision
How is low blood pressure diagnosed?
The doctor will review your symptoms and examine you to determine the cause of your low blood pressure. He/she will check your temperature, pulse, the rate of breathing, and blood pressure. Sometimes, a hospital stay might be needed for a while.
The doctor will ask the following questions:
- What is your normal blood pressure?
- Do you feel dizzy or lightheaded when standing or sitting after lying down?
- Did you faint or become less alert?
- What other symptoms do you have?
- What medicines do you take?
- Have you been eating and drinking normally?
- Have you had any recent illness, accident, or injury?
The doctor may order the following tests:
- Complete blood count (CBC), including blood differential
- Basic metabolic panel
- Blood cultures to check for infection
- X-ray of the abdomen
- X-ray of the chest
How is low blood pressure treated?
Hypotension does not cause any symptoms in a healthy person and often no treatment is needed. When needed, treatment depends on the cause of the low blood pressure and the symptoms.
When symptoms occur due to a drop in blood pressure, sit or lie down immediately and raise your feet above heart level.
Severe hypotension caused by shock is a medical emergency, which needs treatment right away. When it happens, the doctor may give:
- Medicines to increase blood pressure
- Medicines to improve heart strength
- Other medicines, such as antibiotics
- Blood through a needle (IV)
For low blood pressure that occurs after standing up too quickly, the doctor may recommend the following treatment:
- If medicines are the cause, your doctor may change the dosage or switch you to a different medicine.
- Your doctor may suggest drinking more fluids to treat dehydration.
- Your doctor may recommend wearing compression stockings to help keep blood from collecting in the legs. This will help keep more blood in the upper body.
For people with neurally mediated hypotension (NMH), the following self-care measures will help:
- Avoid triggers like standing for a long period of time
- Drink enough fluids and keep yourself adequately hydrated
- Increase salt in your diet
The doctor may prescribe medicines in severe cases.
This feature is for informational purposes only and is not intended to substitute the expert guidance of a doctor. We advise seeing a doctor if you have any health concerns.