What Is Neurally Mediated Hypotension?

Hypotension refers to a state where the arterial circulation arterial pressure is lower than normal. Because hypertension often causes damage to important organs such as the heart, brain, and kidney in the clinic, it has received much attention. The World Health Organization also has clear regulations for the diagnosis of hypertension, but there is no uniform standard for the diagnosis of hypotension. It is generally considered that the upper limb arterial blood pressure in adults is lower than 12/8 kPa (90 / 60mmHg) as hypotension. According to the etiology can be divided into physiological and pathological hypotension, according to the form of onset can be divided into acute and chronic hypotension.

Basic Information

English name

hypotension

Visiting department

cardiology

Common causes

Secondary to severe tuberculosis, malignant tumors, malnutrition, cachexia, etc.

Common symptoms

Dizziness, dark eyes, soft limbs, cold sweats, palpitations, oliguria, or shock

Causes of hypotension

Physiological hypotension

It means that in some healthy people, the blood pressure measurement value has reached the low blood pressure standard, but without any conscious symptoms. After long-term follow-up, except for low blood pressure, the organs of the human body are free of abnormalities such as ischemia and hypoxia, and do not affect life.

2. Pathological hypotension

In addition to lowering blood pressure, it is often accompanied by varying degrees of symptoms and certain diseases.

(1) Primary hypotension refers to a state of hypotension with no obvious cause, such as physiological hypotension (physical hypotension), which is more common in elders and women with weak constitution.

(2) Secondary hypotension refers to a decrease in blood pressure caused by a disease in an organ or system of the human body. Such hypotension can occur quickly in a short period of time, such as major bleeding, acute myocardial infarction, severe trauma, infection, allergies and other reasons caused by a sharp reduction in blood pressure. In most cases, hypotension occurs slowly and can gradually increase, such as hypotension secondary to severe tuberculosis, malignant tumors, malnutrition, cachexia, etc.

Clinical manifestations of hypotension

According to the onset of hypotension, it is divided into two categories, acute and chronic.

Acute hypotension

Acute hypotension refers to a sudden and significant decrease in blood pressure from normal or higher levels. Clinically, symptoms such as dizziness, dark eyes, soft limbs, cold sweats, palpitations, and oliguria are often caused by ischemia of important organs such as the brain, heart, and kidney In severe cases, syncope or shock appears.

2. Chronic hypotension

Chronic hypotension refers to a state in which blood pressure continues to fall below the normal range.

(1) Constitutional hypotension is generally considered to be related to heredity and physical weakness. It is more common in women and elderly people aged 20 to 50. Those with mild symptoms may have no symptoms, and those with severe symptoms may experience mental fatigue, dizziness, headache, and even fainting. It is more pronounced when summer temperatures are higher.

(2) Orthostatic hypotension The occurrence of hypotension in some patients is related to changes in posture (especially in the upright position), which is called orthostatic hypotension. Orthostatic hypotension is defined as: within 3 minutes of changing the posture to an upright position, the systolic blood pressure decreases> 20mmHg or the diastolic blood pressure decreases> 10mmHg, accompanied by symptoms of hypoperfusion, these symptoms include: dizziness, dizziness, blurred vision, Weakness, nausea, cognitive dysfunction, palpitations, neck and back pain. Elderly patients with simple systolic hypertension are accompanied by diabetes mellitus and hypovolemia, and those with diuretics, vasodilators or psychotropic drugs are prone to orthostatic hypotension.

(3) Secondary hypotension Some diseases or drugs can cause hypotension, such as syringomyelia, high aortic stenosis, mitral valve stenosis, chronic constrictive pericarditis, idiopathic or hypertrophic cardiomyopathy , Hemodialysis patients and chronic malnutrition, as well as taking antihypertensive drugs, antidepressants. Hypotension caused by these diseases can also cause symptoms of hypoperfusion such as dizziness and dizziness.

Hypotension test

Physical examination

In addition to paying attention to the measurement of supine and standing blood pressure in patients with hypotension, we should also pay attention to the measurement of blood pressure in the upper and lower limbs, to exclude arterial stenosis caused by polyarteritis. In addition, the physical appearance, skin color, hair distribution, weight loss, edema, and other general manifestations should be paid attention to during physical examination; the physical examination should pay attention to changes in heart sounds and heart murmurs; the nervous system examination should pay attention to the patient's limb feeling , Sports, and freemasonry.

2. Laboratory and special inspection

According to the history and physical examination, clues for the diagnosis of the cause of hypotension can be obtained, but if the diagnosis is established, it depends on the necessary laboratory or special examination.

If you are suspected of diabetes, you need blood glucose and urine glucose measurements; for cardiovascular diseases, you need to perform ECG, echocardiography, and even angiography. If necessary, you can also perform blood routine, blood electrolytes, troponin, 24-hour ambulatory electrocardiogram, and Invasive electrophysiological examination, upright tilt test, transesophageal echocardiography and other examinations; the diagnosis of endocrine diseases requires evidence of pituitary, adrenal or thyroid function tests. If pulmonary embolism is suspected, blood gas analysis, pulmonary arterial CT, and pulmonary ventilation perfusion scans can be performed. If intracranial or focal neuropathy is suspected, EEG, skull and brain CT and magnetic resonance imaging should be performed.

Hypotension diagnosis

The diagnosis of hypotension is mainly based on arterial blood pressure measurement to achieve hypotension standards. At the same time, pay attention to the following conditions for patients with hypotension to help diagnosis and differential diagnosis.

1. Ask if there are other vascular symptoms and other systemic diseases besides hypotension. If not, consider hypotension.

2. Ask if there are acute or severe cases that cause acute hypovolemia, acute cardiac function decline, or cardiac dysfunction.

3. Ask if you have cardiovascular disease and peripheral vascular disease that cause hypotension, and if you have a history of living on the plateau. Are there any endocrine system diseases and clinical manifestations that cause hypotension? Whether there is metabolic disease or spinal cord disease.

4. Ask when the hypotension occurred, and whether it has a significant relationship with clinical symptoms and posture. Have a long history of bed rest. Is there any cause of autonomic nerve damage caused by surgery or trauma?

5. Ask about the duration of hypotension and the relationship between clinical manifestations and medication.

By inquiring about the above conditions in detail, it can be clear whether hypotension is primary or secondary, and whether it is acute hypotension. Combined with other clinical data, the primary cause can be identified.

Hypotension treatment

1. Etiology treatment

Weak nutrition should be strengthened; those who have wasting diseases such as tuberculosis should step up treatment; those who are caused by drugs can stop using or adjust the dosage. If hypertensive patients feel uncomfortable after their blood pressure drops too fast after taking antihypertensive drugs, they should adjust the administration method and dosage under the guidance of a doctor. For orthostatic hypotension patients, be careful not to overdo it when standing in the supine position, or use hands Help to prevent wrestling due to hypotension.

2. Properly strengthen exercise

Have a regular life to prevent excessive fatigue, because extreme fatigue can lower blood pressure. To maintain a good mental state, properly strengthen exercise, improve physical fitness, improve the regulating functions of nerves and blood vessels, accelerate blood circulation and reduce the incidence of orthostatic hypotension. The elderly should exercise according to environmental conditions and their physical conditions. , Such as Tai Chi, walking, aerobics, etc.

3 Adjust your diet

You should not eat too much at every meal, because too much blood will reduce the return of blood to the heart. Elderly people with low blood pressure can drink some light salt water in the morning or eat a slightly salty diet to increase water intake. More water enters. Blood can increase blood volume, which can increase blood pressure; drink tea in moderation, because the caffeine in tea can excite the respiratory center and cardiovascular system.