low blood pressure



OVERVIEW

Definition

Hypotension is a condition in which arterial blood pressure values in the upper extremities fall below the lower limit of the normal range (90/60 mmHg), either as a physiologic manifestation or as an abnormal manifestation caused by disease, drugs, etc.

Classification

According to whether it is a disease state or not, it is divided into physiological hypotension and pathological hypotension.

Acute hypotension and chronic hypotension are classified according to the time of onset and duration of the disease.

Morbidity

Hypotension can occur in people of any age and gender.

The epidemiology of different types of hypotension varies.

Upright hypotension (also known as postural hypotension) occurs more often in middle-aged men.

Causes

Causes

Physiologic Factors

Hypotension caused by physiologic factors usually has no obvious symptoms and no obvious damage to the body, and the common causes are listed below.

Heredity: There are many people in the family whose blood pressure is below normal, but it is not caused by disease.

Physical: Low blood pressure occurs when a person is thin and weak and eats a small amount of food, but is in good health and does not have a disease that causes lowered blood pressure.

Pregnancy: A woman’s blood pressure will be relatively low during pregnancy and will return after delivery.

Postprandial hypotension: A decrease in blood pressure may occur when you have eaten for 2 hours, mostly in the elderly.

Disease Factors

Heart disease: myocardial infarction, heart failure, arrhythmia, etc.

Severe infectious diseases.

Severe allergic diseases.

Nervous disorders.

Endocrine diseases: hypothyroidism, hypoadrenocorticism, etc.

Excessive water loss in the body: severe diarrhea, severe vomiting, excessive exercise or hot weather leading to heavy sweating, etc.

Diseases that cause bleeding from organs: gastrointestinal bleeding due to peptic ulcer or cirrhosis, ectopic pregnancy (ectopic pregnancy, etc.).

Severe pain.

Trauma

Bleeding from ruptured blood vessels due to trauma can cause hypotension.

Includes open and closed (wounds not visible on the surface of the body, but there is bleeding inside).

Commonly seen in cuts to the extremities, stab wounds to the chest and abdomen, and abdominal impact injuries.

Medications

Hypotension can be caused by overdose of drugs such as vasodilators, drugs that decrease myocardial contractility, and diuretics.

Pathogenesis

Decrease in heart function

Diseases or medications cause a decrease in the contractile function of the heart muscle, which weakens the blood flow rate and pressure on blood vessels, and low blood pressure occurs.

Dilation of blood vessels

Low blood pressure occurs when disease or medication causes dilation of blood vessels with unchanged blood flow.

Decrease in blood volume

Bleeding due to trauma or disease, medication, exercise, environment, and disease lead to a large loss of water in the body, and if it is not replenished in time, the total amount of blood decreases, and low blood pressure can occur.

Symptoms

Main Symptoms

Hypotension: Measurement of upper arm arterial blood pressure below 90/60 mmHg during the day in a quiet and non-sleeping state.

Dizziness: manifested by a feeling that the body or things around you are spinning, or an inability to stand still.

Blackout: This is characterized by darkness in front of the eyes.

Syncope: This is a temporary loss of consciousness that can last from a few seconds to several minutes.

In severe cases, there will be pale, unresponsive, unconscious, coma and other signs of severe ischemia in the brain.

The above manifestations can be associated with a change in body position, such as occurring when suddenly switching from a squatting or lying position to a standing or sitting position, which is called upright hypotension.

Other symptoms

Hypotension caused by different etiologic factors may have other symptoms besides those mentioned above.

Heart disease may cause palpitations, chest pain, and chest tightness.

Infectious diseases may include fever, cough, phlegm, nausea and vomiting.

Allergic diseases may include rashes and itching.

Endocrine diseases may include fatigue and obesity.

Bleeding from organs or traumatic bleeding may cause cold, clammy skin and pallor.

Consultation

Department of Medicine

Cardiovascular Medicine

If your blood pressure in the upper extremities is lower than 90/60mmHg, or if you experience dizziness, blackness, fainting, or pallor, you should seek medical attention.

Emergency Department

If you have a pale face, cold skin, unconsciousness, coma, or have suffered a traumatic injury, you should seek medical attention immediately.

Preparation for medical treatment

How to get to the clinic: registration, preparation of documents, common problems

Tips

Do not abuse drugs without the doctor’s permission, so as to prevent drugs from affecting the relevant examinations and interfering with the diagnosis and treatment of the disease.

Preparation Checklist

Pay special attention to the time of onset of symptoms, special manifestations, etc.

What is the discomfort? How long has the discomfort lasted?

Are there any symptoms such as dizziness, blurred vision, etc.?

Is there any significant change in urine output?

Are there any symptoms such as fatigue or panic attacks?

When are these symptoms more noticeable?

Have you ever had your blood pressure checked? Is your blood pressure below normal?

What diseases have you had before?

Are you suffering from kidney disease, endocrine disease, cardiovascular disease, etc.?

Is there a family history of low blood pressure?

What medications have you taken recently?

Are there any allergic foods or medications?

Test results in the last six months, which can be brought to the doctor’s office

Blood biochemistry

Routine blood tests

C-Reactive Protein

Urine routine

Ultrasound, vascular ultrasound

Echocardiography

Coronary Angiogram

Magnetic Resonance Imaging (MRI)

Ambulatory Blood Pressure Monitoring

Electrocardiogram, ambulatory electrocardiogram

Medication use in the last 3 months, bring medication box or package to doctor if available

Drugs to raise blood pressure: epinephrine, norepinephrine, phenylephrine, mesalamine

Drugs to improve cardiac function: Digoxin, Deacetyltrichoside, Amiodarone

Anti-infective drugs: penicillin

Anti-allergic drugs: diphenhydramine, glucocorticoids, sodium cromoglycate,

Vasoconstrictor: Midodrine

Diagnosis

Diagnosis is based on

Medical history

Family history of low blood pressure.

Thin body and low diet.

Being in a state of pregnancy.

Have a disease or abnormal condition such as heart disease, severe infectious disease, severe allergic disease, neurological dysfunction, endocrine disease, excessive water loss gastrointestinal bleeding, ectopic pregnancy (ectopic pregnancy).

Have a disease that causes severe pain.

Have had a traumatic injury.

Use of medications such as vasodilators, medications that decrease the contractility of the heart muscle, diuretics, etc.

Symptoms

There is dizziness, blackout, fainting, cold and clammy skin, unresponsiveness and coma.

Measurement of blood pressure in the upper extremities is below 90/60 mmHg.

Weak pulse and increased or slowed pulse rate may be present.

Fever may be present if there is an infectious disease.

Respiratory abnormalities

May be manifested as clear consciousness, unresponsive, awake but unable to communicate, not easy to wake up or coma.

Physical signs

There may be persistent pale skin and excessive sweating.

If caused by trauma, it may present with deformity of the injured area, open wounds or swelling of the skin.

Allergic conditions may present with a generalized or localized rash.

There may be tenderness in the abdomen, pressure at the site of injury, or localized structural abnormalities.

There may be a decrease in skin temperature and excessive sweating on the surface of the skin.

In the presence of diseases such as heart failure, cardiac tapping may show an enlarged heart border.

Patients with infectious lung diseases may have abnormal sounds on lung auscultation.

Patients with heart disease may have abnormal sounds on cardiac auscultation.

Increased bowel sounds may be present on abdominal auscultation in cases of gastrointestinal bleeding and severe diarrhea.

Laboratory Tests

White blood cell count, red blood cell count, and hemoglobin concentration may be checked.

Clarify the presence of bleeding and evaluate the severity of bleeding; clarify the presence and severity of infection.

Check for elevated C-reactive protein.

It can clarify whether there is an inflammatory response, as well as the severity of the inflammatory response.

Test liver function, kidney function, blood lipids, and blood glucose.

Clarify the cause of hypotension, or exclude other diseases.

Precautions: Fasting must be maintained before the test, i.e. fasting for 6 hours and 4 hours.

Urine specific gravity, urine protein, etc. can be checked.

It can clarify the cause or exclude other diseases.

Precautions: The test should be retained in mid-stream urine, i.e., a portion of the urine should be discharged first, and then the urine after that should be left in the urine cup, stop urinating when it is not completely discharged, and drain the remaining urine in the body after removing the urine cup.

It can confirm whether a woman is pregnant or not.

To clarify whether there is a possibility of ectopic pregnancy.

Includes thyroid hormones, adrenal hormones, etc.

Can clarify the cause or rule out other diseases.

Imaging

To check the function and structure of the heart.

It can clarify the presence of cardiogenic hypotension.

Precautions:

Thyroid, kidney, adrenal gland, pelvis and other organs and tissues, arteries and veins can be examined.

Ultrasound can clarify the etiology. Vascular ultrasound can clarify the presence of hypotension due to vascular pathology.

Precautions:

Examine the coronary arteries and other blood vessels.

It can clarify the etiology.

Precautions:

Examines organs or tissues such as the brain, adrenal glands, and kidneys.

It can clarify the cause of the condition, the extent of the effect of low blood pressure on the organs, etc., or rule out disease.

Precautions:

Electrocardiogram

Examines the electrical signals of the heart over a short period of time.

Precautions:

Examination of the electrical signals of the heart over a period of time (mostly 24 hours) and the relationship between changes in the electrical signals of the heart and time of day and daily behavior.

Can clarify the presence of hypotension due to heart function.

Ambulatory blood pressure monitoring

Checks blood pressure over a period of time (mostly 24 hours) and its relationship to time and daily behavior.

It can clarify whether there is hypotension caused by abnormal blood pressure regulation.

Precautions:

Blood Pressure Measurement Test

Measure blood pressure in the lying and standing positions every minute for 3 to 5 consecutive measurements.

The test is performed when upright hypotension is suspected. If the test result shows a drop in blood pressure of more than 30/20 mmHg, it is positive and indicates the presence of upright hypotension.

Microbiological examination

Bacterial culture and drug susceptibility testing of sputum and blood.

Used when bacterial infection is suspected. It can clarify the presence or absence of bacterial infection, as well as determine the type of bacteria and provide information for the development of a treatment plan.

Detection of viral antigens, viral antibodies, etc.

Can clarify the presence of viral infection, as well as the type and severity of the infection.

Endoscopy

Gastroscopy and colonoscopy are performed to examine the stomach, colon, and other parts of the body.

It can clarify the presence of gastrointestinal bleeding and other conditions that cause low blood pressure, as well as the severity of the bleeding, and can be directly treated if necessary.

Differential Diagnosis

Cerebrovascular disease

Similarities: Dizziness, blackout, syncope, confusion, coma.

Differences: Cerebrovascular disease is a disease in which ruptured or blocked blood vessels in the brain cause abnormal brain function. Blood pressure may be elevated, and symptoms such as hemiparesis and slurred speech may also occur. It can be differentiated by head CT and other tests.

Hypertension

Similarities: Dizziness, blackouts, fainting, confusion, coma.

Differences: Hypertension is characterized by a blood pressure that exceeds the upper limit of normal (140/90 mmHg). It can be differentiated by blood pressure measurement and other tests.

Hypoglycemia

Similarities: Dizziness, blackouts, fainting, cold clammy skin, unresponsiveness, unconsciousness, coma.

Differences: In hypoglycemia, blood glucose is lower than the lower limit of normal, blood pressure may be normal or high, and there may be hunger, babbling, and other symptoms. It can be differentiated by measuring blood sugar and other tests.

Non-hemorrhagic anemia

Similarities: Dizziness, pale skin, blackouts, fainting, unresponsiveness.

Differences: Non-hemorrhagic anemia is related to diet, blood or bone marrow disorders, and may also present with weakness. It can be differentiated by blood tests.

Treatment

Purpose of treatment

Remove the cause of the disease, replenish blood volume or raise blood pressure, and prevent damage to the brain and other vital organs.

General treatment

Rest

Take rest and prevent falls. When dizziness or blackout occurs, stop activity immediately, sit down or lie down to rest, and stand up slowly when symptoms are relieved.

If unconsciousness occurs, someone should assist you to lie on your side to avoid suffocation by secretions in the mouth.

Hydration

If hypotension is caused by profuse sweating or severe diarrhea, in the absence of nausea or vomiting, drink to rehydrate.

Drinks can be chosen from sports drinks, light salt water, sugary drinks or plain water.

Drinking should be done in small amounts and slowly, around 200 ml at a time.

Stop drinking when nausea or vomiting occurs.

Stop bleeding

When bleeding is caused by trauma, stop bleeding immediately while waiting for an ambulance.

If the bleeding is small, you can use medical gauze, towel or clothes to stop bleeding by pressing directly on the bleeding area.

If the bleeding is from the limbs and the amount of bleeding is large, a tourniquet can be made from a tourniquet or necktie and tied to the wound 5 cm above to stop the bleeding, and the time of tying the tourniquet should be recorded.

If no obvious bleeding is seen after the trauma, but there is a sign of low blood pressure, it should be kept still in the same place.

Improve diet and living habits

Hypotension caused by a poor diet or physical condition can be regulated by improving diet and moderate exercise.

Adjustment of medication

If the low blood pressure is caused by medication, you should consult the doctor and change the medication according to the doctor’s requirement.

Medications

There are many medications available for the treatment of hypotension, only some of which are listed below. Specific medications should be used according to your doctor’s instructions.

Drugs to raise blood pressure

To raise the blood pressure in a short period of time to prevent the brain and other organs from functioning abnormally due to low blood pressure.

They are often used in acute hypotension emergency.

Commonly used drugs include epinephrine, norepinephrine, phenylephrine, and mesalamine.

Drugs to improve heart function

By improving the function of the heart, improve the dynamics of blood circulation, relieve the symptoms of low blood pressure.

Commonly used in heart failure, arrhythmia and other cardiac diseases caused by low blood pressure.

Commonly used digoxin, deacetyl furanoside, amiodarone, etc.

Anti-infective drugs

The main purpose is to control infection and inhibit the growth or proliferation of pathogens.

Used in the treatment of infectious diseases.

Commonly used penicillin and cephalosporins, etc.

Anti-allergy drugs

Inhibit allergic reactions, or used for severe allergy-induced hypotension emergency.

Commonly used drugs include H1 antihistamines (e.g., diphenhydramine, chlorpheniramine, etc.), glucocorticoids, leukotriene receptor antagonists (e.g., montelukast sodium, etc.), and mast cell stabilizers (e.g., sodium cromoglycate, ketotifen, etc.).

Severe allergies must be accompanied by epinephrine.

Replacement of body fluids

Replace lost fluids promptly to maintain blood pressure.

Used in excessive water loss, bleeding caused by disease or trauma, when blood volume is insufficient.

Commonly used drugs include glucose solution, saline, hydroxyethyl starch injection, iron dextrose, etc.

Hemostatic drugs

Used for bleeding caused by stress and peptic ulcer.

Such as octreotide, which can improve the blood supply of gastric mucosa.

Drugs to improve endocrine function

Restore the function of human organs to normal by treating endocrine diseases.

Used to treat endocrine diseases, thus improving the symptoms of hypotension.

Commonly used in the treatment of hypothyroidism with levothyroxine sodium, hydrocortisone, cortisone acetate for the treatment of hypoadrenocorticism.

All of the above drugs should be used under the supervision of a physician.

Volume expanders

Such as fludrocortisone, may improve upright hypotension by increasing blood volume.

Adverse effects such as hypertension, edema and cardiac enlargement should be noted.

Vasoconstrictors

For all causes of hypotension, especially upright hypotension.

Such as Midodrine, which elevates blood pressure by limiting vasodilatory capacity.

Others

E.g. Droxidopa, improves symptoms of upright hypotension caused by norepinephrine deficiency.

e.g. Acarbose, which lowers postprandial blood glucose levels, thereby controlling blood pressure, note that dosage needs to be adjusted when combined with digoxin.

Surgery

Hypotension caused by trauma, gastrointestinal bleeding, ruptured tubal pregnancy, etc. requires surgical treatment.

Surgery at this time is mostly emergency surgery, and fasting and water fasting on the way to the hospital is sufficient.

During and after surgery, there may be increased bleeding, infection of the surgical site or wounds, etc. Following the doctor’s instructions can reduce the risk of these conditions occurring.

Traditional Chinese Medicine (TCM) Treatment

The doctor will choose the appropriate treatment according to the manifestation (Diagnosis and Treatment).

Treatment should be carried out according to the doctor’s instructions.

Avoid believing in partial remedies, local remedies, secret remedies, etc. leading to aggravation of the condition or causing other lesions.

Blood transfusion treatment

In case of low blood pressure caused by severe bleeding, blood transfusion treatment is required.

Depending on the condition, the doctor may choose to transfuse component blood such as red blood cells, plasma, or whole blood.

Before transfusion, blood type test should be conducted according to the doctor’s requirements to reduce the risk of hemolysis.

During blood transfusion, use anti-allergic drugs as required by the doctor.

If rash, itchy skin, palpitation, sweating, unconsciousness, etc. occur during blood transfusion, the doctor should be notified promptly and the transfusion should be suspended.

Fever may occur after blood transfusion, which is normal in most cases.

Rash, itchy skin, palpitation, profuse sweating and persistent fever after blood transfusion should be notified to the doctor promptly.

Prognosis

Cure

Hypotension caused by physiologic factors does not require treatment.

Hypotension caused by some diseases can be restored to the prehypotensive state or normal state through timely treatment.

Some serious diseases (e.g. heart failure) require long-term medication to keep blood pressure within a safe range.

Low blood pressure caused by bleeding due to trauma or disease can be restored to its pre-trauma or pre-bleeding state with prompt treatment.

Low blood pressure caused by medication can be restored to the state before the low blood pressure by changing the medication.

Hazards

Low blood pressure can cause fainting, which can lead to falls and injuries.

Severe hypotension can lead to abnormal brain function, leaving sequelae such as hemiplegia, limb movement disorder, or life-threatening.

Daily

Daily management

No surgery

Eat small and frequent meals, with eight minutes of fullness at main meals.

Fruits can be consumed between meals to supplement vitamins.

Increase the intake of proteins, sugars (carbohydrates), lipids, iron and folic acid, e.g. eat more eggs, milk, lean meat, fish, animal liver, animal blood and citrus fruits as appropriate.

Pay attention to dietary hygiene, wash your hands before eating, and avoid eating raw and cold food.

Avoid spicy and stimulating foods, such as raw onions, raw garlic, chili peppers and curry.

Avoid stimulating beverages such as strong tea, coffee, alcohol, etc.

Avoid foods that clarify allergies.

Moderately reduce the intake of refined carbohydrates, such as white rice and white flour.

A salt-restricted diet is generally not recommended.

Drink reasonable amounts of water (adults should ensure at least 1500 ml per day) to avoid malnutrition and dehydration in the body.

Processed foods and flavoring agents also contain sodium. Insufficient or excessive sodium intake should be avoided, and consult a medical professional or dietitian if necessary.

Avoid exertion and late nights.

Avoid sitting up or standing up suddenly.

Exercise in moderation, avoid over-exercise and avoid exercising in hot environments.

Follow your doctor’s request for regular review.

Seek medical attention if symptoms worsen or new symptoms appear.

After undergoing surgery

Depending on the site of surgery and the degree of trauma, you should follow the doctor’s requirements for meals after surgery. If abdominal surgery is involved, you should wait until you are out of breath to start eating.

Adjust the structure of nutrient mix and gradually transition from liquid or semi-liquid food to normal diet as the body recovers.

For those who are unable to eat or have insufficient nutritional intake, enteral or parenteral nutrition should be supplemented according to the doctor’s instruction.

Choose light and easy-to-digest food, avoid spicy and stimulating food, such as chili, pepper, coffee, ginger, garlic, etc.; avoid rough and hard food, do not eat fried food, food with too much dietary fiber, etc., and juice fruits and vegetables.

Ensure adequate sleep and avoid staying up late.

Pay attention to the range of motion and speed of activity of the upper limbs to avoid pulling the wound.

Get out of bed in time according to the doctor’s requirements, avoid excessive bed rest.

Pay attention to the strength of coughing and sneezing.

Follow the doctor’s prescribed time for review and change of medication.

Consult the doctor promptly if there is any discomfort such as bleeding from the incision, abnormal secretion from the incision, fever, or worsening chest pain.

Prevention

Improve diet: Ensure adequate nutrition, avoid picky eating, partiality, or dieting to lose weight.

Pay attention to dietary hygiene: wash and cook food before consumption, avoid eating unclean food.

Improve living habits: Ensure adequate sleep, avoid staying up late and overworking.

Reasonable exercise: Be careful to replenish water, sodium, potassium, glucose and other substances during activities, and avoid exercising in a hot environment.

Avoid allergies: Avoid eating or contacting allergy-prone foods, substances or environment.

Avoid trauma: Pay attention to safety and minimize accidents. Avoid behaviors such as fighting and brawling.

Actively treat diseases: diseases that may cause low blood pressure, such as coronary heart disease, heart failure, arrhythmia, hypothyroidism, hypoadrenocorticism, chronic gastroenteritis, peptic ulcer, hepatitis or cirrhosis of the liver, should be actively treated.

Doing pregnancy checkups: Women who are likely to become pregnant should visit the doctor for checkups in a timely manner.

Reasonable use of medication: Use medication according to the doctor’s instruction, avoid adding, reducing or stopping medication on your own. Consult the doctor in time if any discomfort occurs during the process of medication.