Presentation on theme: "Haematopoiesis and Anemia"— Presentation transcript:
1Haematopoiesis and Anemia 造血与贫血Department of PediatricsSoochow University Affiliated Children’s Hospital
2Main Point-要点 Master clinical manifestation and diagnosis of anemia Know well etiology and classification of anemiaKnow well principle of treatment of anemiaUnderstand hematopoiesis trait and blood change in childhood
3一、Development of the haematopoietic system -造血系统的发育 Three anatomic stages of haematopoiesis prior to birthmesoblastic stage-中胚叶造血期hepatic stage-肝脏造血期myeloid stage-骨髓造血期
4GESTATIONAL AGE PHASE LOCATION TABLE 1 GESTATIONAL HEMATOPOIESISGESTATIONAL AGE PHASE LOCATION2 weeks - 2 months Mesoblastic Wall of yolk sac6 weeks - birth Hepatic Liver2 1/2 month - birth Myeloid Bone Marrow
5Mesoblastic haematopoiesis -中胚叶造血 Mesoblastic hematopoiesis occurs in extraembryonic structures, principally in the yolk sac wall where small nests of blood cell production can be visualized, and begins between the 10th and 14th days of gestation. These nests are referred to as "blood islands". By 6–8 wk of gestation the liver replaces the yolk sac as the primary site of blood cell production, and by 10–12 wk extraembryonic hematopoiesis has essentially ceased.
6Hepatic haematopoiesis -肝脏造血 Islands of blood cell development occur within the liver parenchyma from 6 weeks to birth. Although the liver is the dominant site of hematopoiesis for the first half of gestation, blood cell production also occurs at lesser intensity within the spleen.
7Myeloid haematopoiesis -骨髓造血 Hematopoiesis within bone marrow begins in the clavicle at about 2 1/2 months. Activity continues to rise until myeloid tissue becomes the major site of hematopoiesis in the latter half of gestation. Myeloid hematopoiesis is centered in most bone marrow (red marrow) during intrauterine life. [Fig1. 2]
8Each hematopoietic organ houses distinct hematopoietic populations Each hematopoietic organ houses distinct hematopoietic populations. At 18–20 wk of gestation, >85% of the cells in the fetal liver are erythroid and virtually no neutrophils are present .[Fig 3]In contrast, at the same time, <40% of the cells within the bone marrow are erythroid and ≤15% are neutrophils. The subpopulations of leukocytes present in the liver and marrow also differ with gestation.
10Figure 2 Contrast chart of haematomopesis before/after birth
11Figure 3 Maturation and differential chart of haematopoiesis
122、Haematopoiesis after birth When bone marrow develops, it eventually assumes the task of forming most of the blood cells for the entire organism. However, maturation, activation, and some proliferation of lymphoid cells occurs in secondary lymphoid organs (spleen, thymus, and lymph nodes). In children, hematopoiesis occurs in the marrow of the long bones such as the femur and tibia. In adults, it occurs mainly in the pelvis, cranium, vertebrae, and sternum.
13The red marrow is then very gradually replaced by inactive, fatty, yellow, lymphoid marrow. The latter begins to develop in the shafts of the long bones and continues until, by years, red marrow is present only in the upper ends of the femur and humerus and in the flat bones of the sternum, ribs, cranium, pelvis and vertebrae.However, because of the growth in body and bone size that has occurred during this period, the total amount of active red marrow (approximately g) is nearly identical in the child and the adult.
14Extramedullary hematopoiesis -髓外造血 In some cases (for instance infections or anemias), the liver, thymus, and spleen may resume their haematopoietic function, if necessary. This is called extramedullary hematopoiesis. It may cause these organs to increase in size substantially. When situation has been improved, these organs will recover to normal size.
153.Normal developmental changes in blood cells 1) Erythrocyte and hemoglobinThe hemoglobin and erythrocyte are relatively high in the term newborn infant because of the low oxygen tension prevailing and erythropoietin(EPO) increasing in utero.RBC x1012/L, Hb g/L
16Physiological anemia -生理性贫血 These values subsequently decline, reaching a nadir (the lowest number) at 2-3 months for term infants. It owns self-limiting and gets adult level at the age of twelve.RBC 3.0x1012/L, Hb 100g/L or so
172) White blood cells and differentiation As already mentioned granulocytes is the collective name given to three types of white blood cell. Lymphocytes are produced in bone marrow from primitive precursors, the lymphoblasts and prolymphocytes.
19Figure 5 Two cross of granulocytes and lymphocytes
20PlateletsPlatelets are produced in bone marrow by a process known as thrombopoiesis. It is the same as adult at birth.x109/L
21Table 2 Normal Hematological values Hemoglobin MCV White cell Platelets(g/dl) (fL) (x109/L) (x109/L)Cord bloodat all ages3 months6monthsto 6 yearsyearsAdult
22Haemoglobins present at different ages Hb typeChainsTimescalesEmbryonic HbHbFα2γ2Predominant haemoglobin at 8 weeks; 90% of Hb at 6 months and 70% at birth. Less than 2% at 1 year of age and thoughout lifeAdult HbHbAα2β2Dectecable early in the fetus and forms % of Hb at 6 months of gestation and 30% at birthHbA2α2δ22-3% during adult life, 1:30 ratio of HbA2 :HbA
23二、Outline of Anemia-贫血概述 1. Definition of Anemia-定义Anemia, one of the more common blood syndrome, occurs when the level of healthy Hb/red blood cells (RBCs) in the body becomes too low. This can lead to health problems because RBCs contain hemoglobin, which carries oxygen to the body's tissues. Anemia can cause a variety of complications, including fatigue and stress on bodily organs.
24Anemia can be caused by many things, but the three main bodily mechanisms that produce it are: a) inadequate production of RBCs –RBCs生成不足b) excessive destruction of RBCs –RBCs破坏过多c) blood loss –失血Among many other causes, anemia can result from inherited disorders, nutritional problems (such as an iron or vitamin deficiency), infections, some kinds of cancer, or exposure to a drug or toxin.
26Normocytic anemia-正细胞性贫血 Figure 6 Causes of the normocytic anemias High reticulocyte levels Low reticulocyte levelsCoomb’s testNormal WBC and Decreased WBCPositve Negative platelets: and/or platelets:Membrane defects:spherocytosis Red cell aplasia Aplastic anemiaAutoimmune Hemoglobin defects:sickle cell LeukemiaDisease Enzyme deficiencies: Hypersplenismglucose 6-phosphate dehydrogenase InfectionsRed cell fragmentation: Drughemolytic uraemic syndrome Renal diseaseFigure 6 Causes of the normocytic anemias
272、 Symptoms and Signs-症状和体征 If your child has anemia, the first symptoms might be mild skin paleness and decreased pinkness of the lips and nailbeds. These changes may happen gradually, though, so they can be difficult to notice. Other common signs include:-irritability-fatigue-dizziness, lightheadedness, and a rapid heartbeat
28If the anemia is caused by excessive destruction of RBCs, symptoms also may include jaundice, a yellowing of the whites of the eyes, an enlarged spleen, and dark tea-colored urine.In infants and preschoolers, iron deficiency anemia can result in developmental delays and behavioral disturbances, such as decreased motor activity and problems with social interaction and attention to tasks. Research indicates that developmental problems may last into and beyond school age if the iron deficiency is not properly treated.
293、Diagnosing Anemia -贫血的诊断 In many cases, doctors don't diagnose anemia until they run blood tests as part of a routine physical examination. A complete blood count (CBC) may indicate that there are fewer RBCs or Hb than normal[Table 5]. Other diagnostic tests may include:
30Table 5 The criterion of anemia Age Hemoglobin concentration< 28 days < 145 g/L1～4 months < 90 g/L4～6 months < 100g/L6 months～6 years < 110g/L6～14 years < 120g/L
31Blood smear examination(血涂片检查): Blood is smeared on a glass slide for microscopic examination of RBCs, which can sometimes indicate the cause of the anemia.Iron tests(铁检测): These include total serum iron and ferritin tests, which can help to determine whether anemia is due to iron deficiency.Hemoglobin electrophoresis(血红蛋白电泳): Used to identify various abnormal hemoglobins in the blood and to diagnose sickle cell anemia, the thalassemias, and other inherited forms of anemia.
32Bone marrow aspiration and biopsy(骨髓穿刺和活检): This test can help determine whether cell production is happening normally in the bone marrow. It's the only way to diagnose aplastic anemia definitively and is also used if a disease affecting the bone marrow (such as leukemia) could be causing of the anemia.Reticulocyte count(网织红细胞计数):A measure of young RBCs, this helps to determine if RBC production is at normal levels.
33Figure 7 Peripheral blood smear of iron deficiency anemia
34Figure 8 Bone marrow smear of megaloblastic anemia
354、Treatment-治疗1）Treatment for anemia depends on its cause. It's important not to assume that any symptoms your child may be having are due to iron deficiency. Be sure to have your child checked by a doctor.a）If your child has iron deficiency anemia, the doctor may prescribe medication as drops (for infants) or as a liquid or tablet (for older kids), which usually must be taken for as long as 3 months to rebuild the body's store of iron. The doctor also may recommend adding certain iron-rich foods to your child's diet or reducing milk intake.
36b）If your teenage daughter is anemic and has heavy or irregular menstrual periods, her doctor may prescribe hormonal treatment to help regulate the bleeding.c）Folic acid and vitamin B12 supplements may be prescribed if the anemia is traced to a deficiency of these nutrients, although this is rare in children.
37d）Anemia caused by an infection will usually improve when the infection passes or is treated. If a certain medication appears to be the cause, your doctor may discontinue it or replace it with something else — unless the benefit of the drug outweighs this side effect.2）Depending on the cause, treatment for more severe or chronic forms of anemia may include:
38a）transfusions of normal red blood cells taken from a donor b）removal of the spleen or treatment with medications to prevent blood cells from being removed from circulation or destroyed too rapidlyc）medications to fight infection or stimulate the bone marrow to make more blood cells
39d）In some cases of sickle cell anemia, thalassemia, and aplastic anemia, bone marrow transplantation may be used. In this procedure, bone marrow cells taken from a donor are injected into the child's vein; they then travel through the bloodstream to the bone marrow and begin producing new blood cells.
405、Preventing Anemia -贫血的预防 Whether anemia can be prevented depends on its cause. Currently, there is no way to prevent anemia due to genetic defects affecting the production of RBCs or hemoglobin.However, you can help prevent iron deficiency, the most common form of anemia. Before following any of these suggestions, be sure to talk them over with your doctor:
41Cow's milk consumption. During the first 6 months of life, babies are usually protected against developing iron deficiency by the stores of iron built up in their bodies before birth. But after month 6, they often don't get enough iron through breast milk alone or regular cow's milk (which contains less iron than fortified infant formula).Regular cow's milk can cause some infants to lose iron from their intestines, and drinking lots of it can make a baby less interested in eating other foods that are better sources of iron.
42For these reasons, regular cow's milk is not recommended for children until they reach 1 year of age and are eating an iron-rich diet. In addition, they should not drink more than ounces ( ml) of milk each day. If you can't get your child to eat more iron-rich foods, speak with your doctor about giving your child an iron supplement.
43Iron-fortified cereal and formula. These products can help ensure that your baby is getting enough iron, especially during the transition from breast milk or formula to solid foods.
44Well-balanced diet. Make sure that your kids regularly eat foods that contain iron. Good choices include iron-fortified grains and cereals, red meat, egg yolks, leafy green vegetables, yellow vegetables and fruits, potato skins, tomatoes, molasses, and raisins.If your child is a vegetarian, you'll need to make an extra effort to ensure sufficient iron sources because iron found in meat, poultry, and fish is more easily absorbed than iron found in plant-based and iron-fortified foods.
45Also, be aware that certain food combinations can inhibit or promote absorption of iron. For example, drinking coffee or tea (including iced tea) with a meal can significantly lower the amount of iron absorbed. On the other hand, vitamin C helps the body absorb iron.
46Summary-小结 Hematopoiesis consists of two phases and three stages. Physiological anemia and extramedullary hematopoiesis are special phenomena in childhood.Anemia is syndrome,not a kind of specific disease.It is very important for treatment for anemia to seek its causes and find the way to cure.Health education can help prevent iron deficiency, the most common form of anemia.