Compensation

Introduction Compensation is a protective mechanism of the human body. For example, if you have two kidneys, after removing one kidney, in order to maintain your normal urinary function, the kidney on the other side will gradually become more powerful (behaving as big as the original) to make up for the missing. The function of that kidney, this is the compensatory effect. When a person bleeds, the heart rate increases to increase the amount of blood pumped by the heart, while the blood vessels contract to reduce the volume of the blood vessels. However, if the patient's bleeding volume is quite large and the compensation mechanism will not be sufficient for compensation, a drop in blood pressure will occur. If the bleeding stops, the fluid moves from the rest of the body into the blood circulation, restoring blood volume, and then the blood pressure begins to rise. Finally, new blood cells are produced and blood volume is fully restored. Blood transfusion is a way to quickly restore blood volume.

Cause

Adapting or compensating for a physiological phenomenon required in a physiological or pathological condition by enhancing the function of an organ or tissue. The tissue or organ that performs the compensatory function is not only functionally enhanced, but also accompanied by an increase in volume. For example, due to the need of physical labor, the muscles of the extremities become hypertrophy and firm, and the contractile force is strengthened. When the main artery is blocked, the blood supply function is compensated by the enlarged collateral circulation.

an examination

Related inspection

Electrocardiogram mammography

Blood pressure depends on three factors: the amount of blood pumped by the heart, the blood volume of the blood vessels, and the volume of the blood vessels.

The more pump bleeding (cardiac output) per minute, the higher the blood pressure. If the heart rate slows or the heart contraction weakens, such as after a myocardial infarction, the heart pumping volume will decrease. Excessive heart rate can also reduce the effective pumping capacity of the heart, thereby reducing cardiac output.

The more circulating blood volume, the higher the blood pressure. Blood loss due to dehydration and hemorrhage can reduce blood volume and cause blood pressure to drop.

The smaller the volume of the blood vessel, the higher the blood pressure. Therefore, vasodilation causes blood pressure to drop and vasoconstriction to increase blood pressure. Sensors (especially receptors located in the neck and chest) continuously monitor blood pressure. When they perceive a change caused by any of the above three factors, these receptors will trigger other compensatory factors to compensate to maintain blood pressure stability. The nerves transmit signals from the receptors and brain to the following key organs:

The heart regulates the frequency and intensity of the heart contraction (changing the amount of blood pumped by the heart, the kidneys regulating the discharge of water (changing the circulating blood volume), and the blood vessels contract or expand the blood vessels (changing the volume of the blood vessels).

Thus, when the blood vessels dilate and the blood pressure drops, the sensor immediately signals that the heart is transmitted through the brain to increase the frequency of heart beats to increase the amount of blood pumped by the heart. As a result, blood pressure is small even if there is fluctuation.

However, these compensation mechanisms also have certain limits. For example, when a person has bleeding, the heart rate is increased to increase the amount of blood pumped by the heart, and the blood vessels contract to reduce the volume of the blood vessels. However, if the patient's bleeding volume is quite large and the compensation mechanism will not be sufficient for compensation, a drop in blood pressure will occur. If the bleeding stops, the fluid moves from the rest of the body into the blood circulation, restoring blood volume, and then the blood pressure begins to rise. Finally, new blood cells are produced and blood volume is fully restored. Blood transfusion is a way to quickly restore blood volume.

Poor function of the compensatory mechanism for maintaining blood pressure also leads to hypotension. For example, as long as any disease damages the signaling function of the nerve, the regulatory mechanism of compensation will not work properly.

Differential diagnosis

The tendency to hemorrhage is a common manifestation of many different diseases and different causes of bleeding. In order to clarify the reasons, clinical and laboratory data must be comprehensively analyzed to understand the patient's past history and to combine the current bleeding conditions to arrive at the correct conclusion. Among them, laboratory tests are more important.

(1) To examine the history of hemorrhagic diseases, such as bleeding from childhood, minor injuries, trauma, or bleeding after minor surgery. Should be considered for hereditary hemorrhagic disease, adulthood should consider the acquisition of bleeding, need to find the primary disease; skin, mucosal purpura with abdominal pain, joint pain and normal platelets should consider allergic purpura; skin mucosa purpura, menstrual volume Many, low platelet counts need to consider thrombocytopenic purpura, more women.

(2) Physical examination should pay attention to the traits and parts of bleeding. Allergic purpura occurs in both lower limbs and buttocks, varies in size, is symmetrically distributed, and can be accompanied by rashes and urticaria. Thrombocytopenic purpura or platelet dysfunction is often a needle-like bleeding site with a systemic scattered distribution.

Scurvy is characterized by bleeding around the hair follicle. Hereditary telangiectasia has vasospasm in the lips, tongue, and cheeks. Hepatosplenomegaly, lymphadenopathy, jaundice, etc., can provide a clinical diagnosis of primary disease.

Differential diagnosis:

Hemorrhagic cerebral infarction also has hemorrhagic lesions on CT findings. It should be differentiated from primary cerebral hemorrhage and brain tumor hemorrhage. Sometimes it is necessary to have a original CT slice to confirm the diagnosis.

1. Primary cerebral hemorrhage Since the advent of CT, the clinical diagnosis of cerebral hemorrhage is not difficult.

The main clinical basis:

(1) Sudden onset of physical activity or emotional agitation.

(2) Onset of illness, symptoms of limb dysfunction and increased intracranial pressure in a few minutes or hours, may have headache, nausea and vomiting.

(3) There are signs of nervous system localization.

(4) History of previous hypertension, especially those who have not undergone regular treatment.

(5) Brain CT scan: There is a high-density shadow at the time of the disease, and there is a mass effect around the low-density edema zone. The hematoma with a diameter greater than 1.5 cm can be accurately displayed. It can determine the location of the hemorrhage, the size of the hematoma, whether it breaks into the ventricle, whether there is brain edema and cerebral palsy, almost 100% diagnosis. Hemorrhagic cerebral infarction is a clinical manifestation of cerebral infarction, and hemorrhagic lesions occur on the basis of cerebral infarction.

2. Patients with brain tumor hemorrhagic brain tumor bleeding usually have symptoms of increased intracranial pressure such as headache, nausea, vomiting, and examination of optic disc edema and signs of nervous system localization. On this basis, the condition suddenly aggravates, and the brain CT scan shows: The density of cystic changes or necrosis in brain tumors is high, and the blood plane is visible. Uneven high density shadows are sometimes seen. The tumor tissue has an enhanced response during enhanced scanning.

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