Hypotension: Low BP Causes, Symptoms, Complications,Treatment
Hypotension (a.k.a: Low Blood Pressure) is the pressure in the arteries when the heart pumps the blood. This condition is seen even in healthy adults, but the blood pressure (BP) can become normal after a short duration whereas the disease-related hypotension requires medical attention.
What is Hypotension?
Hypotension is the condition in which BP is lower than the normal range. Normal BP is 120/80 mmHg, where 120 is the systolic BP and 80 is the diastolic BP. If BP is ≤ 90/60 mmHg, then the condition is considered as hypotension.
Types of Hypotension:
There are three types of hypotension that may occur due to various reasons. The characteristic, causes and the high risk population are classified in the table below:
|Orthostatic hypotension||Occurs while standing up or sitting down very rapidly||Due to a decrease in blood supply because of hypovolemia or low blood volume||Older adults|
|Postprandial hypotension||Occurs 30 to 60 min after having meals||Due to consuming meals rich in carbohydrates, blood circulation improves in the gastrointestinal system, thus decreasing blood supply to the brain and other organs||Older adults|
|Neurally-mediated hypotension||Occurs after standing for prolonged periods||Due to neurological deficits||Children and young adults|
Orthostatic hypotension is a condition in which BP decreases rapidly.
What Causes Hypotension?
Causes of hypotension are:
- Hypovolemia: Low blood volume or hypovolemia leads to hypotension. This condition may occur due to severe bleeding, hyperthermia (high body temperature), severe dehydration due to vomiting or diarrhea, inadequate fluid intake, anemia, and use of diuretics.
- Vasodilation: Dilatation of blood vessels also causes hypotension. This condition occurs due to sepsis (blood infection) or anaphylaxis (allergic reaction).
- Heart diseases: Presence of heart diseases such as arrhythmia and ischemia can cause hypotension.
- Metabolic disorders: Presence of adrenal and thyroid disorders can cause hypotension.
- Use of certain medications: Calcium channel blockers, antidepressants, antiparkinsonian drugs, alpha blockers, and beta blockers can also lead to hypotension.
- Obstruction due to clots: Formation of clots such as in case of pulmonary embolism leads to blockage in the blood flow causing hypotension.
- Pregnancy: Hypotension also occurs in pregnant women as there is a requirement of blood supply for both mother and fetus. However, this condition may become normal after delivery.
Hypotension usually doesn’t show any symptoms. However, some individuals may experience symptoms such as:
- Dizziness or feeling light-headed
- Palpitations (fast and irregular heartbeat)
- Increased thirst
- Cold or sweaty skin
- Rapid breathing
- Vision disturbances such as blurred vision
An individual with hypotension may develop symptoms gradually. If BP is 80/60 mmHg, nausea, fatigue, and dizziness may appear. If BP is 70/50 mmHg, the person may experience vision disturbances and confusion. If BP further lowers to 50/35 mmHg, it may lead to coma or death.
Risk Factors of Hypotension:
The factors that increase the risk of hypotension are:
- Age above 60
- Prolonged exposure to heat
- Vitamin B12 and folate deficiency
- Consumption of alcohol
- Endocrine problems such as thyroid insufficiency and diabetes
- Sitting for a prolonged time
Complications of Hypotension:
As blood supplies oxygen, hypotension may cause a decrease in the supply of oxygen. In severe cases, brain and heart may get damaged due to oxygen deprivation leading to coma.
Hypotension can lead to shock. It occurs due to a sudden drop in blood pressure or blood volume. It is a life-threatening condition and requires immediate medical attention. It is also called hypotensive emergency. It occurs due to conditions such as anaphylaxis, sepsis, or severe burns.
Diagnosis of Hypotension:
The doctor may initially assess the symptoms by performing a physical examination followed by BP and heart rate measurement. A sphygmomanometer is used to measure BP. The BP is measured in a sitting or lying position. In this condition, the heart rate may increase to 20 to 30 beats than the regular heartbeat.
Electrocardiogram (ECG) can be performed to monitor rhythm and activity of the heart. It helps to detect arrhythmias and structural abnormalities of heart.
In case of orthostatic hypotension, BP (Blood Pressure) and heart rates are measured in lying, sitting, and standing position with an interval of two minutes between measurements in each position.
Tilt table test is performed in case of orthostatic hypotension. The doctor makes you lie down on a table and tilts it to 60 to 80 degrees as that upper part of the body is raised. Then the changes in BP and heart rate are monitored.
Blood tests are also performed to detect the percentage of haemoglobin, sugar levels, or thyroid hormone levels.
Asymptomatic or mild hypotension and hypotension in healthy individuals usually don’t require treatment. Treatment is given in case of hypotensive emergencies or hypotension caused due to underlying conditions.
The main aim of the treatment in emergency cases is to increase blood volume.
- Intravenous fluids or normal saline if there is no renal failure
- Blood transfusion, in case of anemia (low hemoglobin levels)
- Monitoring urine output
- Dopamine, if hypotension persists
It is essential to identify the cause of hypotension before providing treatment. If the cause is unclear, symptomatic treatment can be given along with improving BP.
If hypotension is due to medications, the dose of medication is altered. If dose cannot be changed, another medication can be prescribed.
In case of pulmonary embolism, wear compression stockings to improve blood supply and avoid sitting by crossing legs.
For patients with orthostatic hypotension:
- Avoid prolonged sitting or standing. Take a short break or sit for a while if you have to stand for a long time.
- Avoid changing positions rapidly.
Prevention and Cure of Hypotension:
Following certain measures can help in early recovery and prevention of hypotension. They include:
- Consuming a healthy diet that has more of fruits and vegetables
- Increasing dietary intake of the salt
- Taking frequent meals, small meals in short duration
- Drinking more liquids
- Limiting alcohol consumption
- Having coffee as caffeine increases BP
- Avoiding diet rich in carbohydrates
Consuming foods rich in vitamin B12 and folic acid such as eggs (reduces anemia)