High bloody face

Introduction Hair bun is the main sign of high altitude polycythemia, and more than 95% of patients have different degrees of hair loss. Lips, cheeks, auricle edges, nails and other nail beds are blue-purple, facial capillary expansion is purple-red stripes, forming a unique face of the disease, that is, "plateau multi-blood face". Chronic hypobaric hypoxia is the underlying cause of this disease. Long-term heavy smoking in the plateau will impede the transmission of oxygen, reduce the oxygen uptake of tissues, and aggravate hypoxemia, leading to the occurrence of hyperbilirubinemia. Obesity in the highland area, nighttime sleep and breathing disorders, etc. are also likely to induce excessive red blood cell hyperplasia.

Cause

(1) Causes of the disease

Chronic hypobaric hypoxia is the underlying cause of this disease. Long-term heavy smoking in the plateau will impede the transmission of oxygen, reduce the oxygen uptake of tissues, and aggravate hypoxemia, leading to the occurrence of hyperbilirubinemia. Obesity in the highland area, nighttime sleep and breathing disorders, etc. are also likely to induce excessive red blood cell hyperplasia.

(two) pathogenesis

Chronic hypobaric hypoxia is the root cause of this disease. It is caused by many ways and mechanisms to cause erythrocytosis. Although many theories and hypotheses have been put forward, the more concentrated views are:

1. Respiratory drive weakening: The passivation of the ventilatory response is related to the length of time spent on the plateau. The patient's resting lung ventilation is about 70% to 80% of healthy people, tidal volume is 60% to 75%, and there is mild small airway obstruction; blood gas analysis patients' pH is lower than normal, and PaCO2 is increased, suggesting Hypertension has a manifestation of insufficient alveolar ventilation. Passivation of HVR is not the only cause of hyperbilirubinemia, and other factors may exist, leading to the hypothesis that hypoxia inhibits the respiratory center, namely hypoxic ventilatory depression.

Current research suggests that attenuated respiratory drive (whether peripheral or central) is a major cause of significant hypoxemia and relative hypercapnia in patients. However, the causal relationship between them is still unclear. Is it like the patients with high altitude pulmonary edema, the attenuation of ventilation drive occurs before the high red syndrome, that is, whether it is related to heredity, it is a new topic worthy of further discussion. Some people think that this disease is not a single factor, in addition to respiratory-driven factors, a large number of smoking, chronic respiratory infections, nocturnal sleep disordered breathing and obesity hypoventilation syndrome can promote arterial oxygen saturation.

2. The role of erythropoietin: erythropoietin (EPO) is a glycoprotein hormone with a molecular weight of approximately 39,000. It mainly acts on the erythropoietin receptor on the erythroid committed progenitor cell membrane, promotes the proliferation and differentiation of these committed progenitor cells, accelerates red blood cell maturation and prevents apoptosis (Apoptosis). Fetal and neonatal EPO are secreted by hepatocytes, and adulthood is mainly secreted by tubulointerstitial fibroblasts, but the liver retains the ability to produce EPO.

Hypoxia, whether low-pressure (plateau) or blood-borne (anemia) can stimulate the production of EPO. In general, when the renal oxygen receptor is stimulated by hypoxia, the tubulointerstitial fibroblasts secrete EPO and stimulate the original cells of the bone marrow, promote the division of nuclear red blood cells, accelerate the maturation of red blood cells, and thus increase the number of red blood cells in the blood.

As a result, on the one hand, it increases the oxygen carrying capacity of hemoglobin, increases oxygen transmission, and improves tissue hypoxia; on the other hand, if the hematocrit exceeds 60%, the blood viscosity is significantly increased, the blood flow is slow, and the blood is stagnant in the microcirculation. Even thrombosis occurs, which hinders the transmission of oxygen, thus aggravating tissue hypoxia.

3. Hemoglobin-oxygen affinity reduction: About 97% of the oxygen transported by the blood binds to Hb and is present in red blood cells. The binding and dissociation of oxygen to Hb is a reversible reaction, namely Hb O2óHbO2. During the oxygenation or oxygenation process, an S-shaped curve, that is, an oxygen separation curve, can be formed due to the different conformations of Hb. The oxygenation curve has important physiological significance. It is affected by pH, PCO2, temperature and 2,3-diphosphoglycerate (2,3-DPG), of which 2,3-DPG is especially important. 2,3-DPG is the product of the red blood cell glycolysis branch. The increase of 2,3-DPG in the blood can be combined with Hb, thus reducing the affinity of Hb and oxygen. The oxygen ion shift curve is shifted to the right and the oxygen release is increased.

After the human body rushed into the plateau, the concentration of 2,3-DPG increased significantly, which is the compensation performance of the body for hypoxic suits. However, the relationship between changes in 2,3-DPG and hyperbilirubinemia is not well understood. Eaton found that 2,3-DPG in patients with high redness was 23% higher than normal people at the same altitude; in the 4300m area, patients' whole blood and red blood cell 2,3-DPG were significantly higher than local healthy people, and PaO2 is negatively correlated and positively correlated with P50 (PO2 when SaO2 is equal to 50%). Therefore, the increase in 2,3-DPG concentration in the plateau increases oxygen transmission and increases tissue oxygen uptake, but its abnormal elevation can cause a decrease in free hemoglobin in the lungs, a significant decrease in blood oxygen affinity, and oxygen uptake from the alveoli. The process is difficult, and SaO2 is decreased; the result is the synthesis of 2,3-DPG, which leads to further reduction of SaO2, which forms a vicious circle and progresses to more severe erythrocytosis. Therefore, the excessive concentration of 2,3-DPG is one of the manifestations of the human body's maladaptive adaptation to the plateau.

Although this disease is a systemic multi-system disease, there are very few cases of direct death from high-redness. The pathological damage of A hyperosmia is very extensive, with multiple systemic changes, the most affected by heart, brain and lung, and the degree of damage is also serious. The manifestation of the brain is that the surface of the brain parenchyma is shallow, the blood vessels of the brain and pia mater are dilated and congested, or the blood vessels are ruptured, and there are spotted or flaky hemorrhage in the brain; brain cells are swollen and interstitial edema. Necrosis of nerve cells, localized or extensive softening. Heart disease does not occur in patients with simple hyperactivity. If the heart has obvious pathological changes, it is considered to be a high altitude heart disease. The surface of the lungs is dark red and the texture is relatively solid; the alveolar wall is thickened, the cavity is enlarged or the interstitial edema is interstitial. The pulmonary capillaries are highly dilated and congested, the pulmonary arterioles are thickened, and the thrombus is formed in the lumen. Other organs, such as the adrenal gland, digestive tract, kidney and spleen, also have bleeding, thrombosis and tissue necrosis.

an examination

Related inspection

Blood oxygen saturation blood routine arterial blood gas analysis arterial oxygen partial pressure (PaO2) refers to pulse oxygen

Symptom

The disease is mostly chronic, and there is no clear onset time, which usually occurs when you migrate to the plateau for one year, or the original acute high altitude disease is delayed. Hypertension is an anoxia-induced injury of various organs caused by increased blood viscosity and slow blood flow. The severity of each organ is different, and the clinical symptoms are different. The changes are very complicated. The most common symptoms are headache, dizziness, shortness of breath, fatigue, and memory loss. The severity of clinical symptoms is related to the degree of tissue hypoxia caused by changes in hematology. After returning to the plains from a hypoxic environment, the hemoglobin and hematocrit returned to normal, and the symptoms gradually disappeared, but they relapsed when they returned to the plateau. Peruvian scholars summarized the common symptoms and signs of high red syndrome: headache, shortness of breath, fatigue, wilting, palpitations, sleep disorders, tinnitus, poor appetite, cyanosis, conjunctival capillary congestion, muscle and/or joint pain, paralysis Finger (toe), finger toe numbness, abnormal feeling. Domestic scholars have counted 360 cases, and their common symptoms are: dizziness, headache, shortness of breath, chest tightness, fatigue, joint pain, anorexia, weight loss, memory loss, and insomnia. In addition, women's irregular menstruation, male impotence, loss of libido, etc. have also been reported.

2. Signs

Hair blemishes are the main cause of this disease, and more than 95% of patients have different degrees of hair loss. Lips, cheeks, auricle edges, nails and other nail beds are blue-purple, facial capillary expansion is purple-red stripes, forming a unique face of the disease, that is, "plateau multi-blood face". The ocular membrane is highly congested, the tongue purple tongue is thick and chapped, and the pharyngeal mucosa is black or blue-purple. About 17.7% of patients had clubbing and 12.8% had nail depression. Some patients have facial and lower extremity edema, and the liver and spleen can be swollen. The general rule of heart rhythm, a few people with bradycardia, or with sinus arrhythmia. In about 20% of cases, I-II murmurs can be heard in the apical region and pulmonary valve area, and the second sound of the pulmonary artery is hyperactive or split. The blood pressure can be high or low, and the pulse pressure difference is small.

(1) Migrants living in the plateau above 3000m above sea level, or a few inhabitants.

(2) has headache, dizziness, shortness of breath, fatigue, sleep disorders, cyanosis, eyeball combined membrane congestion.

(3) Hemoglobin > 200 g / L, hematocrit > 65% and red blood cell count > 6.5 × 10 ¹² / L.

(4) Symptoms and signs disappeared after leaving the hypoxic environment, and relapsed when returning to the plateau.

(5) Excluding erythrocytosis caused by other diseases.

Differential diagnosis

Differential diagnosis of high blood surface of the plateau:

Secondary erythrocytosis

Mainly caused by chronic bronchitis, emphysema, cyanotic congenital heart disease, thoracic deformity and other erythrocytosis. These diseases have typical symptoms and signs, such as chronic cough, heart murmur, etc., so it is not difficult to identify.

2. Polycythemia vera

Most of the disease is in people over 50 years old. There is no primary disease and cause. The immigration plain can't be recovered, the blood oxygen saturation is normal, and there is no blood surface. The bone marrow changes to the whole hematopoietic hyperplasia and the spleen enlargement.

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