Thalassemia is also called marine anemia. This is a group of hereditary hemolytic anemia. The same feature is that one or more globin peptide chains in hemoglobin are reduced or cannot be synthesized due to the defect of globin gene. The composition of hemoglobin has changed, and the clinical symptoms of this group of diseases are different, mostly chronic progressive hemolytic anemia. The disease is more common in Mediterranean coastal countries and Southeast Asian countries, and has been reported in all provinces south of the Yangtze River in China. Guangdong, Guangxi, Hainan, Sichuan, Chongqing and other provinces have a high incidence rate, which is rare in the north. (1)β thalassemia can be divided into the following three types according to the severity of the disease. 1. Severe type is also called Cooley anemia. The child was asymptomatic at birth, and began to show symptoms at 3 ~ 12 months, showing chronic progressive anemia, pale face, large liver and spleen, dysplasia and often mild jaundice. With the increase of age, the symptoms become more and more obvious. Due to compensatory hyperplasia of bone marrow, the bone becomes larger and the medullary cavity becomes wider, which first occurs in metacarpals, followed by long bones and ribs. After 1 year-old, the skull changes obviously, which is characterized by skull enlargement, forehead bulge, high cheekbone surface, nose bridge collapse and eye distance widening, forming a special face shape of thalassemia. Children are often complicated with bronchitis or pneumonia. When hemosiderosis is complicated, there are too many iron deposits in myocardium and other organs such as liver, pancreas and pituitary gland, which cause corresponding organ damage symptoms, the most serious of which is heart failure, which is the result of myocardial damage caused by anemia and iron deposition and is one of the important causes of child death. If the disease is not treated, it will die before the age of 5. Laboratory examination: Peripheral hemogram showed small cell hypopigmentation anemia, red blood cells with different sizes, enlarged central shallow staining area, abnormal, target-shaped, fragmented red blood cells and nucleated red blood cells, spotted red blood cells, polychromatic red blood cells, Howe-Pericorpuscles, etc. Reticulocytes are normal or elevated. Bone marrow image shows that the red blood cell system is obviously active, mainly in the middle and late stage, and the changes of mature red blood cells are the same as those in peripheral blood. The osmotic fragility of red blood cells was significantly reduced. The content of HbF is obviously increased, mostly > 0.40, which is an important basis for the diagnosis of severe β -thalassemia. X-ray film of skull showed that the inner and outer plates of skull became thinner, the barrier widened, and vertical short hair-like bone spurs appeared between cortical bones. 2. Mild patients have no symptoms or mild anemia, and the spleen is not big or slightly larger. After a good course of disease, he can live to be old. This disease is easily overlooked and often found in family surveys of critically ill patients. Laboratory examination: the mature red blood cells have slight morphological changes, the osmotic fragility of red blood cells is better than normal or decreased, and the hemoglobin electrophoresis shows that the content of HbA2 is increased (0.035 ~ 0.060), which is the characteristic of this type. HbF content is normal. 3. Intermediate type has more symptoms than early childhood, and its clinical manifestations are between mild and severe, moderate anemia, mild or moderate spleen, unnecessary jaundice and slight changes in bones. Laboratory examination: the peripheral blood picture and bone marrow picture changed seriously, the osmotic fragility of red blood cells decreased, the content of HbF was about 0.40 ~ 0.80, and the content of HBA 2 was normal or increased. (2) Thalassemia 1. The rest of the patients were asymptomatic. The morphology of red blood cells is normal. Hb Bart's content in umbilical cord blood was 0.0 1 ~ 0.02 at birth, and disappeared after 3 months. 2. Mild patients are asymptomatic. There are slight changes in the morphology of red blood cells, such as unequal size, light staining in the center and abnormity. The osmotic fragility of red button cells decreased; Denatured globin body was positive; HbA2 and HbF contents are normal or slightly lower. The content of Hb Bart's in cord blood of children was 0.034 ~ 0. 1.40, and it completely disappeared after 6 months of birth. 3. Intermediate type is also called hemoglobin H disease. The clinical manifestations of this type are quite different, and the time and severity of anemia are different. Most of them gradually appear anemia, fatigue, hepatosplenomegaly and mild jaundice after infancy; Older patients may have a special face similar to severe β -thalassemia. Complicated with respiratory tract infection or taking oxidizing drugs and antimalarial drugs can induce acute hemolysis, aggravate anemia and even appear hemolytic crisis. Laboratory examination: the changes of peripheral blood picture and bone marrow picture are similar to those of severe β thalassemia; The osmotic fragility of red blood cells decreased; Denatured globin body was positive; HbA2 and HbF contents are normal. At birth, the blood contains about 0. 25Hb Bart and a small amount of HbH. With the increase of age, HbH gradually replaced Hb Bart, and its content was about 0.024 ~ 0.44. Inclusion body formation test was positive. 4. severe type is also called Hb Bart fetal edema syndrome. Fetuses of 30 ~ 40 weeks often miscarry, stillbirth or die within half an hour after delivery. Fetus is characterized by severe anemia, jaundice, edema, hepatosplenomegaly, ascites and hydrothorax. The placenta is big and brittle. Laboratory examination: morphological changes of mature red blood cells in peripheral blood such as severe β thalassemia, and the number of nucleated red blood cells and reticulocytes increased significantly. Almost all hemoglobin is Hb Bart's or there is a small amount of HbH at the same time, and there is no HbA, HbA2 and HbF. Diagnosis and differential diagnosis According to clinical features and laboratory examination, combined with positive family history, diagnosis can generally be made. When conditions permit, it can be used for gene diagnosis. This disease must be differentiated from the following diseases. 1. Iron deficiency anemia Mild thalassemia has similar clinical manifestations and morphological changes of red blood cells to iron deficiency anemia, which is easy to be misdiagnosed. However, iron deficiency anemia is often caused by iron deficiency, such as the decrease of serum ferritin content, the decrease of iron granule red blood cells outside bone marrow, and the increase of free Ling Ye of red blood cells. It is effective to treat it with iron agent. 2. Infectious hepatitis or cirrhosis is easily misdiagnosed as icteric hepatitis or cirrhosis due to mild anemia of HbH disease, accompanied by hepatosplenomegaly and jaundice, and a few cases may also have liver function damage. However, it can be identified by medical history inquiry, family investigation, erythrocyte morphology observation and hemoglobin electrophoresis. Mild thalassemia does not require special treatment. Moderate and severe thalassemia should be treated by one or more of the following methods. 1. General treatment should pay attention to rest and nutrition, and actively prevent infection. Appropriate supplementation of folic acid and vitamin E. Blood transfusion and iron removal are still one of the important treatment methods at present. A small amount of red blood cell infusion is only suitable for moderate α and β thalassemia, not for severe β thalassemia. For severe β thalassemia, medium and large doses of blood transfusion should be given from the early stage to make the growth and development of children close to normal and prevent bone lesions. The methods are as follows: firstly, the concentrated red blood cells are infused repeatedly to make the hemoglobin content of children reach120 ~150g/L; Then, every 2 ~ 4 weeks, concentrated red blood cells 10 ~ 15 ml/kg were infused to keep the hemoglobin content above 90 ~105 g/L. However, this method is easy to lead to hemosiderosis and should be treated with iron-Austrian mixture at the same time. 3. Desferriamine is commonly used in iron chelating agents, which can increase the excretion of iron from urine and feces, but it can't prevent the gastrointestinal tract from absorbing iron. Iron load is usually evaluated after regular infusion of red blood cells 1 year or 10 ~ 20 units. If there is iron overload (such as SF >；; 1000 μ g/l), using iron chelating agent. Every night, deferoxamine/kloc-0 was injected subcutaneously for 1 2 hours, or added to glucose osmotic solution for 8-12 hours; 5 ~ 7 days a week, long-term application. Or adde into red blood cell suspension for slow infusion. Deferamine has few side effects and occasional allergic reactions, which can cause cataracts and long bone development disorders for a long time. Too much will lead to poor eyesight and hearing. The combined application of vitamin C and chelating agent can enhance the effect of deferoxamine on urinary iron excretion, and the dose is 200rng/ day. 4. Splenectomy Splenectomy is effective for H disease and intermediate β thalassemia, but it is not effective for severe β thalassemia. Splenectomy can weaken immune function, and should be performed after 5 ~ 6 years old, and the indications should be strictly controlled. 5. Hematopoietic stem cell transplantation Allogeneic hematopoietic stem cell transplantation is a method that can radically cure severe β thalassemia at present. If there are HLA-compatible hematopoietic stem cell donors; It should be the first choice for the treatment of severe β thalassemia. 6. The application of chemical drugs in gene activation therapy can increase the expression of γ gene or decrease the expression of α gene, thus improving the condition of β thalassemia. Drugs that have been used in clinic include glucosylurea, 5- azacytidine (5 ~ AZC), cytarabine, Mailuoling, isoniazid and so on, and are currently being explored. Prevention of population census, genetic counseling and premarital guidance are of great significance to avoid marriage between thalassemia gene carriers. Prenatal diagnosis through genetic analysis can diagnose the fetus with severe β -thalassemia and α -thalassemia in the early pregnancy, and terminate the pregnancy in time, thus avoiding the occurrence of fetal edema syndrome and the birth of patients with severe β -thalassemia, which is an effective method to prevent the disease at present.

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