primary orthostatic hypotension
Introduction
Introduction to primary orthostatic hypotension PrimaryOrthostatic Hypotension is a rare disease. In 1925, Bradbury and Eggleston first described in detail the clinical features of this disease as orthostatic hypotension (ie, a significant decrease in blood pressure from a sudden rise in the supine or sacral position), syncope The pulse rate is fixed (ie, there is no corresponding increase in heart rate when standing upright), no sweat, erectile dysfunction and nocturia, etc., called "spontaneous orthostatic hypotension." basic knowledge The proportion of illness: the incidence rate is about 0.002%-0.007% Susceptible people: no special people Mode of infection: non-infectious Complications: dizziness, syncope, coronary insufficiency
Cause
Primary orthostatic hypotension
Secondary to other diseases (30%):
1. Nervous system diseases spinal tuberculosis, spinal cord transection, syringomyelia, infectious polyneuritis, multiple sclerosis, subacute combined degeneration, tremor paralysis and so on.
2. Endocrine and metabolic diseases Adrenal insufficiency, hypopituitarism, hypothyroidism, diabetes, pheochromocytoma and so on.
3. Drug-induced ganglion blockers, antihypertensive drugs, vasodilators, etc.
4. Autonomic neuropathy such as sympathetic surgery.
5. Other amyloidosis, severe anemia, cachexia, prolonged illness and bed rest.
Pathogenesis (20%):
When the human body is standing, due to the influence of the gravity of the earth, about 300 to 400 ml of blood is deposited on the lower limbs, and the amount of blood returning to the heart is reduced. The cardiac output can be reduced by about 25% compared with the lying position, and the blood pressure can be lowered. The normal blood pressure is just beginning. When descending, it can rapidly stimulate the baroreceptors of the carotid sinus and the aortic arch, so that the frequency and rate of inhibitory impulses issued to the vasomotor center are reduced, and the adrenergic sympathetic nerve excitability is increased reflexively and released into the blood. Increased amount of norepinephrine in the surrounding blood vessels and heart, leading to arteriolar contraction and increased heart rate. In addition, vascular system baroreceptors can also cause vasoconstriction effects on venous congestion, as well as increased muscle tone and equal length of lower limbs. Contraction, forcing blood through the venous valve to the heart, this muscle pumping effect can also increase the amount of blood returning, thus preventing a sharp drop in cardiac output. In addition, when the body position changes, hyperventilation usually occurs, resulting in reflex venous tension. Increase, which also contributes to the filling of the heart and the rise of blood pressure, due to the above adjustment machine , It is clear reduction in blood pressure does not occur when the upright from the supine.
Any part or part of the above-mentioned regulatory mechanism can cause orthostatic hypotension. The primary orthostatic hypotension is mainly the central nervous system, especially the autonomic neuron degeneration (especially the sympathetic nervous system). ), which blocks the reflex arc of the baroreceptor, and the lesion can be damaged in the sympathetic nerve, brain stem, hypothalamus, vascular motion center and arteriole wall itself before or after the ecchymosis. Blood vessels (mainly small arteries) and volumetric blood vessels (mainly venules) are not able to effectively reflex contraction, and the heart rate is not increased, so that the effective circulating blood volume is reduced, and the blood pressure is lowered. In addition, some people think that catecholamine metabolism Or a secretory disorder causes nerve conduction disorders, and some vasodilator substances such as bradykinin release in the circulation may also participate in the occurrence of orthostatic hypotension.
Autonomic neurogenesis (30%):
Primary orthostatic hypotension is mainly caused by the central nervous system, especially autonomic neurogenesis (especially the sympathetic nervous system) that blocks the reflex arc of baroreceptors.
Prevention
Primary orthostatic hypotension prevention
1. Actively prevent and treat diseases that cause orthostatic hypotension.
2. For orthostatic hypotension of the elderly, when moving up and changing position, the movement should be slow, avoiding sudden standing.
3. It is advisable to wear elastic stockings, tight pants or elastic bandages to reduce blood stasis in the lower limbs when standing upright.
Complication
Primary orthostatic hypotension complications Complications, dizziness, syncope, coronary artery insufficiency
Primary orthostatic hypotension can occur with darkness, dizziness and even syncope, and severe cases can cause complications such as insufficient blood supply to the coronary arteries.
Symptom
Primary orthostatic hypotension symptoms Common symptoms Upright hypotension, syncope, hypotension, dizziness, pacing frequency, increased blood pressure, low dizziness, pre-existing golden flower oxygen partial pressure, low cold sweat, panic
The most prominent manifestation of primary orthostatic hypotension is normal blood pressure in the supine position, rapid and significant decrease in blood pressure during erect, systolic blood pressure decreased more than 30mmHg, diastolic blood pressure decreased more than 20mmHg, but the heart rate did not change, resulting in a decrease in blood pressure A series of cerebral ischemia, hypoxia, vertigo gradually occurs when the erect is light, and severe stun can occur immediately, so that it is forced to rest in bed for a long time. After lying down, the symptoms of dizziness or syncope can be alleviated. In addition, autonomic nerve damage can occur. Symptoms such as dry skin, less sweating, urination, defecation and libido and erectile dysfunction, etc., because this disease often involves the central nervous system, some cases may gradually appear extraocular muscle paralysis, limb stiffness with gross tremor, expression dull, Symptoms of extrapyramidal injury such as slow movement and gait gait; gait sputum, ataxia, unclear language, nystagmus and other cerebellar damage symptoms and increased muscle tone, hyperreflexia, pathological nerve reflex positive, pronunciation Difficulty and other symptoms of pyramidal tract damage, a small number of patients have paresthesia, mental decline, this type of patient due to The central nervous system damage, also known as the central type, is Shy-Drager syndrome. If there is no central nervous system damage, only the patients with orthostatic hypotension and peripheral autonomic dysfunction are called peripheral orthostatic hypotension.
Examine
Primary erect hypotension check
For hypoxemia caused by endocrine diseases, the corresponding endocrine function and hormone test should be done. If the blood routine test is red, the change of white blood cells will also help to diagnose.
1. Whether there is a change in heart rate and heart rate in the electrocardiogram, whether there is a change in ST-T, and whether there is a pathological Q wave.
2. Cardiac ultrasound and peripheral vascular Doppler ultrasonography are helpful in the diagnosis of cardiovascular hypotension.
3. Cardiac catheterization and angiography can identify peripheral vascular disease and heart disease.
4. X-ray examination through a chest X-ray examination to see if there is a mass to oppress the peripheral large blood vessels.
5. Myelography to understand the presence or absence of spinal cord lesions such as syringomyelia.
Diagnosis
Diagnosis of primary orthostatic hypotension
According to the clinical manifestations of the disease is not difficult to diagnose, but should pay attention to the following points:
1. Some patients with orthostatic hypotension do not occur immediately and need to stand for 1 to 3 minutes before they occur. Therefore, when suspected of this disease, wait at least 5 minutes.
2. When a normal person stands up, there will be a short-term blood pressure drop but the fluctuation is not large, and it will recover within 1~2 minutes. In this case, do not misdiagnose the disease. In the case of syncope, except for this disease, the vasovagal reflex should be excluded. Arterial sinus allergy, urinary syncope and severe arrhythmia (such as complete atrioventricular block, sick sinus syndrome, etc.) caused by syncope.
Patients with hypotension are mainly manifested by insufficient blood supply to the brain, while secondary hypotension caused by endocrine diseases is accompanied by symptoms of endocrine dysfunction. Some patients may present with loss of appetite, abdominal discomfort, indigestion, and increased red blood cells. Leukopenia, decreased resistance can cause infections and other phenomena.
