Systolic blood pressure drops

Introduction Systolic blood pressure is the highest pressure in the arteries when the human heart contracts. The pressure on the inner wall is called systolic blood pressure, also known as high pressure. Plateau hypotension is mainly caused by a decrease in systolic blood pressure, and women have a higher incidence than men. Its mechanism is unclear, may cause autonomic dysfunction due to hypoxia, increased vagal tone, causing bradycardia and decreased peripheral resistance. Some scholars believe that hypoxia is related to the decrease of arteriolar smooth muscle tension and increased capillary opening through the action of certain physiologically active substances. The result is a decrease in cardiac output, a decrease in peripheral vascular resistance, and a decrease in systolic blood pressure, and a decrease in diastolic blood pressure is not as pronounced as systolic blood pressure.

Cause

High altitude disease, also known as mountain sickness and plateau insufficiency, refers to an idiopathic disease that occurs when the human body enters the plateau hypoxia environment. After returning to the plains, it quickly returned to its characteristics. The disease often occurs at altitudes above 3000 m above sea level. The main cause of the disease is hypoxia, cold, dryness, solar radiation, fatigue, and malnutrition can also promote the disease. Plateau disease is divided into acute and chronic according to the onset time.

Reasons for low blood pressure in the plateau:

1. In order to adapt to the hypoxic environment and ensure that the tissue obtains more blood, the plateau people often have capillary proliferation, small blood vessels dilate, and the collateral circulation that is usually not open is also open, so that the surrounding resistance of the blood vessels is reduced, and the diastolic blood pressure is lowered.

2. Plateau people have mild pulmonary hypertension and heavy right heart load. In order to save the energy of cardiac contraction, the systemic pressure is less reflective, and the cardiac output is reduced at rest, which causes the systolic blood pressure to decrease.

3, plateau small arterial wall smooth muscle cells contain low levels of concomitant + contractive stress response is also low. It can be seen that the mildly low blood pressure is an adaptation phenomenon, and it is not necessary to worry about it. If it is treated indiscriminately, it will destroy the physiological balance in the body.

4, a small number of people due to plateau adaptation dysfunction, vasomotor center and autonomic dysfunction, blood tissue histamine content, or adrenal cortical function is insufficient, blood pressure is too low, tissue perfusion is insufficient, ischemia symptoms occur, Plateau hypotension will occur, but its incidence is only 2.27%.

an examination

Check the symptoms:

Hours or one or two days after reaching the plateau, severe headache, dizziness, fatigue, irritability, insomnia, palpitations, shortness of breath, chest bloating, loss of appetite, nausea and vomiting, bloating, diarrhea, vertigo, tinnitus, snoring, hand and foot Hemp or hands twitching, etc., the symptoms vary from person to person. Generally, the symptoms gradually subsided after about 1 week, but they also persisted for a long time or prolonged into chronic high altitude sickness.

Differential diagnosis

Differential diagnosis of systolic blood pressure drop:

First, acute altitude sickness

1. The altitude sickness occurs from the plain rapid into the plateau at an altitude of 3000m or from a low plateau to a higher altitude. Symptoms such as headache, palpitation, shortness of breath, nausea, vomiting, and diarrhea occur, which is called acute altitude sickness. This type is also known as mild or benign acute altitude sickness. The incidence of this type is related to the height and speed of entering the plateau and the factors such as fatigue, emotional stress, cold, and physical load. More than 24 hours after climbing, it usually adapts within 1 to 2 weeks, and the symptoms gradually disappear.

2, high altitude pulmonary edema, also known as pulmonary or severe acute altitude sickness. It is a special type of pulmonary edema that occurs in a hypoxic environment. The incidence rate is about 3%. On the basis of acute altitude sickness, it usually occurs 3 to 48 hours after climbing at an altitude of 4000m or more. There are also those who are 3 to 10 days late. It is characterized by severe cough, coughing pink foam, severe breathing difficulties, not lying down, headache. Severe oliguria, unconsciousness. Symptoms can be quickly relieved after metastasis to a low altitude plateau or back to the plains, another feature of this disease.

3, plateau coma, also known as high altitude cerebral edema or high altitude encephalopathy. Its pathological mechanism is cerebral edema. The incidence is low but it is more likely to cause death. Some people call this disease a malignant high altitude disease. In addition to the symptoms of acute altitude sickness in the early stage, patients often have increased intracranial pressure, such as severe headache, vomiting, delirium, depression or excitement, and paralysis. The patient can also convulsion and sleepiness, which can lead to coma. Physical examination showed signs of increased pulse rate, irregular breathing, and unresponsive pupils to light.

Second, chronic altitude sickness

1. Chronic high altitude polycythemia patients in the plateau emigration or inhabitants who have hemoglobin 200g / L, red blood cells 6.5 × 1012. / L (6.5 million / mm3) and hematocrit 0.65 (excluding other reasons), said For high altitude polycythemia. Patients often have dizziness, headache, memory loss, palpitations, shortness of breath, chest tightness and increased after exercise. There may also be multiple blood spots such as loss of appetite, vision loss and nosebleeds, conjunctival hyperemia, facial capillary exposure.

2. High altitude heart disease refers to a type of heart disease in which right ventricular hypertrophy occurs in the plateau and inhabitants (some patients may still have left ventricular enlargement), and severe cases may have heart failure. More common in young children, the heart is often diffuse or spherical expansion, and the adult pulmonary artery is prominent. Patients often have dizziness, headache, insomnia, palpitations, difficulty breathing after exercise, chest tightness, chest pain and discomfort in the precordial area. Symptoms and signs of heart failure can occur in the advanced stage.

3, plateau blood pressure abnormalities are high altitude hypertension and high altitude hypotension. After the normal blood pressure in the plains, after entering the plateau, the young and middle-aged systolic blood pressure>18.7kPa, diastolic blood pressure>12.0kPa and corresponding symptoms, return to normal after returning to the plains, said high altitude hypertension; after entering the plateau, blood pressure is lower than 12 .O / 6.67kPa, for more than 2 weeks, said plateau hypotension. Generally, those who first arrive at the plateau are prone to high blood pressure, and the fluctuation period is about 1 year. Those who live for a long time or live in the country are prone to high altitude hypotension.

4, chronic high altitude disease mixed type of disease refers to high altitude polycythemia, high altitude hypertension and high altitude heart disease, there are two types of simultaneous existence, known as mixed type. The most common is polycythemia with heart disease and polycythemia with hypertension.

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