Iron deficiency anemia

Introduction Iron deficiency anemia (IDA) is a common anemia caused by the lack of iron in the body and affects hemoglobin synthesis. Before the production of red blood cells is restricted, the iron storage in the body is exhausted, which is called iron deficiency. This anemia is characterized by a lack of stainable iron in the bone marrow, liver, spleen and other tissues, and a decrease in serum iron concentration and serum transferrin saturation. Typical cases of anemia are small cell hypopigmentation. The disease is a common type of anemia and is ubiquitous throughout the world. Causes of iron deficiency anemia: First, the demand for iron is increased and the intake is insufficient, the second is the poor absorption of iron, and the third is excessive blood loss, which will affect the survival of hemoglobin and red blood cells. Iron deficiency anemia (IDA) is a common anemia caused by the lack of iron in the body and affects hemoglobin synthesis. Before the production of red blood cells is restricted, the iron storage in the body is exhausted, which is called iron deficiency. This anemia is characterized by a lack of stainable iron in the bone marrow, liver, spleen and other tissues, and a decrease in serum iron concentration and serum transferrin saturation. Typical cases of anemia are small cell hypopigmentation. The disease is a common type of anemia and is ubiquitous throughout the world. Causes of iron deficiency anemia: First, the demand for iron is increased and the intake is insufficient, the second is the poor absorption of iron, and the third is excessive blood loss, which will affect the survival of hemoglobin and red blood cells.

Cause

[cause]

The mononuclear-macrophage system such as liver, spleen and bone marrow contains about 1000 mg of iron, which can be used by the human body to produce 1/3 of the blood volume of hemoglobin, and almost all of the iron released by hemoglobin decomposition is reused by the human body. Short-term food iron deficiency or iron deficiency increases, and there is generally little iron deficiency. Iron deficiency anemia is easily caused by the following factors.

1. The amount of iron needed is increased and the intake is insufficient.

Children need increased iron during the growing season and during lactation, especially in premature infants, twins or mothers with anemia. The original iron storage of the baby is insufficient. If the milk is only fed by people with less iron, it will not be timely replenished with non-ferrous foods such as eggs, vegetables, meat and animal liver. Iron deficiency anemia. Increased iron supply during pregnancy and lactation, combined with gastrointestinal dysfunction during pregnancy, lack of stomach acid, affecting iron sleep, especially after multiple pregnancy, it is easy to cause iron deficiency anemia. Because of the rapid growth of adolescents, the amount of iron needed to increase, especially in young women, due to menstrual blood loss, iron deficiency can occur if the food consumed for a long time is insufficient. The most common cause is insufficient iron in food, partial eclipse or malabsorption. Heme iron in food is easily absorbed and is not affected by food composition and stomach acid.

Non-heme iron needs to be changed to Fe2 before it can be absorbed. Phosphate, phytic acid, tannins, etc. in vegetables, cereals and tea can affect the absorption of iron. The daily iron requirement for adults is about 1-2 mg. Men with 1 mg/d are enough, and the need for iron for women of reproductive age and adolescents with growth and development should increase from 1.5 to 2 mg/d. If the iron content in the diet is rich and the amount of iron stored in the body is sufficient, iron deficiency will rarely occur. Other causes of inadequate iron intake are drug or gastrointestinal disorders that affect iron absorption, intake of certain metals such as gallium and magnesium, calcium carbonate and magnesium sulfate in antacids, and H2 inhibitors used in ulcers. Etc., can inhibit the absorption of iron.

Atrophic gastritis, gastric acid and duodenal surgery, the reduction of gastric acid affects the absorption of iron, etc., are the cause of insufficient iron intake. In addition, an average blood loss of 1300ml (about 680mg iron) during pregnancy requires 2.5mg of iron per day. In the 6 months after pregnancy, 3 to 7 mg of iron is needed every day. The requirement for iron during lactation is increased by 0.5 to 1 mg/d. Insufficient supplementation will lead to a negative balance of iron. If the pregnancy is repeated, the amount of iron needs to increase. Blood donors donate 400ml each time, which is equivalent to 200mg of lost iron. About 8% of male blood donors and 23% of female blood donors have reduced serum ferritin. If you donate blood several times in a short period of time, the situation will increase.

2. Excessive storage iron consumption

Since 2/3 of the total iron in the body is present in the red blood cells, repeated and excessive blood loss can significantly consume the iron storage in the body. Hookworm disease causes long-term loss of chronic small amount of intestinal bleeding, repeated upper gastrointestinal ulcer bleeding, many years of anorectal bleeding or excessive menstrual flow in women, and eventually leads to insufficient iron storage in the body, resulting in iron deficiency anemia. In addition, paroxysmal nocturnal hemoglobinuria, mechanical hemolysis caused by artificial mechanical heart valves, and idiopathic pulmonary hemosiderosis can cause anemia due to long-term urinary iron loss. The amount of iron lost by normal people from the gastrointestinal tract, urinary tract and skin epithelial cells is about 1 mg per day. Women have more iron loss during menstruation, childbirth and breastfeeding. Excessive iron loss in the clinic is often caused by gastrointestinal bleeding in men, while women are often due to menorrhagia.

3. Excessive iron loss

The detached iron can be lost as the gastrointestinal epithelial cells age and continually fall off. In the case of atrophic gastritis, major gastrectomy, and steatorrhea, the rate of epithelial cell renewal is increased, so the loss of free iron is also increased. Iron deficiency not only causes a decrease in heme synthesis, but also reduces the activity of iron-containing enzymes (such as cytochrome oxidase) in red blood cells, affecting the electron transport system, which can cause abnormalities in lipid, protein and glucose metabolism, resulting in abnormal red blood cells. Destruction within the spleen shortens its life span. The iron in the human body is in a closed loop. Under normal circumstances, iron absorption and excretion maintain a dynamic balance, the human body generally does not lack iron, only in the case of increased need, insufficient iron intake and chronic blood loss caused by long-term iron negative balance caused by iron deficiency.

an examination

Related inspection

Blood routine serum iron (Fe) bone marrow cell line morphology examination

an examination

1. Bloody mild anemia is positive cell positive anemia. Severe anemia is typical small cell hypochromic anemia, mean red blood cell volume (MCV) hemoglobin content (MCH) red blood cell mean hemoglobin concentration MCHC.

2. Bone marrow like bone marrow shows active cell proliferation, mainly due to increased erythrocytosis, younger red blood cells and cytoplasmic imbalance.

3. Serum iron serum iron is significantly reduced.

4. The erythrocyte protoporphyrin is reduced in heme synthesis due to iron deficiency, and the red blood cell free protoporphyrin 500 g / L (normal 200-400 g / L).

5. Small cell hypochromic anemia Hemoglobin (Hb) male is less than 120g / L, female is less than 110g / L, MCV is less than 80fl, MCH is less than 26pg, MCHC is less than 0.31.

6. There are clear causes of iron deficiency and clinical manifestations.

7. Serum iron is less than 10.7mol/L (60g/dl), and the total iron binding capacity is greater than 64.44 gmol/L (360g/dl).

8. Transferrin saturation is less than 15%.

9. The extracellular iron disappeared from the bone marrow, and the intracellular iron was less than 15%.

10. The cytosine protoporphyrin (FEB) is greater than 0.9 mol/L (50 g/dl).

11. Serum ferritin (SF) is less than 14 g / L.

12. Iron treatment is effective.

13. Chronic infectious anemia.

14. Iron granulocyte anemia.

15. Vitamin B6 reactive anemia.

16. Thalassemia.

Careful inquiry and analysis of medical history, plus physical examination can be used to obtain clues to diagnose iron deficiency anemia, to confirm the diagnosis must be confirmed by the laboratory. Clinically, iron deficiency and iron deficiency anemia are divided into three stages: iron deficiency, iron deficiency erythropoiesis and iron deficiency anemia. The diagnostic criteria are as follows:

1. Iron deficiency or potential iron deficiency at this time only the consumption of stored iron in the body. It can be diagnosed by (1) plus any of (2) or (3).

(1) There are clear causes and clinical manifestations of iron deficiency.

(2) serum ferritin.

(3) Bone marrow iron staining showed iron granule cells.

2. Iron deficiency erythropoiesis indicates that red blood cells intake is less than normal, but the reduction of intracellular hemoglobin is not obvious. It meets the diagnostic criteria for iron deficiency and can be diagnosed by any of the following.

(1) Transferrin saturation.

(2) Erythrocyte free protoporphyrin > 0.9 mol / L or > 4.5 g / g Hb.

3. Iron deficiency anemia red blood cell red blood protein reduction is obvious, showing small cell hypochromic anemia. The diagnosis is based on: 1 diagnosis of iron deficiency and iron deficiency erythropoiesis. 2 small cell hypochromic anemia. 3 iron treatment is effective.

Diagnostic evaluation:

(1) Determination of serum iron is affected by many factors: it cannot be used as an indicator for the diagnosis of iron deficiency. It should be emphasized that serum total iron binding capacity is >64.44mol/L (360g/L), and transferrin saturation is anemia. . Similarly, if the total iron binding force is 15%, it cannot be diagnosed as iron deficiency.

(2) In the past, it was thought that the staining of bone marrow iron showed that the disappearance of bone marrow irritable iron was the "gold standard" for the diagnosis of iron deficiency: it was rarely used after the determination of ferritin by radioimmunoassay in the 1970s, because the conditions of bone marrow iron staining required production conditions. High, and often affected by the inconsistent results of bone marrow samples from different parts, so the clinical serum ferritin has replaced the bone marrow iron staining method to become the "gold standard" for the diagnosis of iron deficiency. It is currently considered that serum ferritin 1g / L is equal to 100mg Iron storage.

(3) Many patients with iron deficiency anemia often have a combination with various chronic diseases (including inflammation, tumor and infection): serum ferritin levels are affected by chronic diseases. The criteria for serum ferritin in patients with chronic diseases with iron deficiency have not been unified (some literatures believe that it should be greater than 60-140 g/L). In addition to careful analysis of clinical and laboratory findings, it is advisable to further measure ferritin receptors (which should be increased in the absence of iron) or erythroferrin.

Differential diagnosis

Mainly differentiated from other small cell hypochromic anemia

1. globin-producing anemia (thalassemia) There is often a family history, and most target red blood cells are seen in blood samples. Fetal hemoglobin (HbF) or hemoglobin A2 (HbA2) is increased in hemoglobin electrophoresis. The patient's serum iron and transferrin saturation, bone marrow dyeable iron increased.

2. Chronic disease anemia Although the serum iron is reduced, the total iron binding capacity will not increase or decrease, so the transferrin saturation is normal or slightly increased. Serum ferritin is often elevated. The number of iron granules in the bone marrow decreased, and the iron particles and hemosiderin particles in macrophages increased significantly.

3. Iron granulocyte anemia is rare in clinical practice. Occurs in the elderly. Mainly due to iron utilization barriers. Often small cell positive pigmented anemia. Serum iron is increased and total iron binding is normal, so transferrin saturation is increased. The iron granules and iron granules in the bone marrow increased significantly, and most of the circular iron granule cells were observed. Serum ferritin levels are also elevated.

[clinical manifestations]

The severity of clinical manifestations is mainly determined by the degree of anemia and its rate of occurrence. Acute blood loss is caused by rapid disease, even if the degree of anemia is not heavy, it will cause obvious clinical symptoms, and chronic anemia due to slow onset, the body can gradually adapt to symptoms without adjustment.

1. Symptoms are sallow or pale, tired and tired, loss of appetite, nausea, bloating, diarrhea, difficulty swallowing. Dizziness and tinnitus, even fainting, a little activity that is anxious, palpitations discomfort. In patients with coronary arteriosclerosis, angina can be induced. Women may have irregular menstruation, amenorrhea, and so on.

Special performance

The special manifestations of iron deficiency are: angular cheilitis, atrophy of the tongue, and glossitis of the tongue. Severe iron deficiency may have key nails (anti-armor), loss of appetite, nausea and constipation. Patients in Europe often have dysphagia, angular cheilitis, and abnormal tongue called the Plummer-Vinson or Paterson-Kelly syndrome, which may be related to the environment and genes. Dysphagia is due to the formation of a mucosal network at the junction of the hypopharynx and the esophagus. It can even form a cuff-like structure around the lumen, which binds the opening of the esophagus. It is often necessary to surgically remove these nets or to expand the stenosis, and the supplement of iron alone does not help.

Non-anemia symptoms of iron deficiency in non-anemic symptoms: children with growth retardation or behavioral abnormalities, manifested as irritability, irritability, lack of concentration in school and decreased academic performance. The eclipse is a special manifestation of iron deficiency, and may also be the cause of iron deficiency. The mechanism of its occurrence is unclear. Patients often cannot control a single "food" such as ice cubes, clay, starch, etc. Iron can disappear after treatment.

2. Signs

For a long time, people may have nails shrinking, not smooth, anti-A, pale skin mucous membranes, dry skin, and dry hair. The tachycardia, the heart beats strongly, and the systolic murmur can be heard in the apex or the pulmonary valve area. Severe anemia can lead to congestive heart failure and edema can also occur. About 10% of patients with iron deficiency anemia have mild splenomegaly. The reason is unclear. No special pathological changes were found in the spleen of the patient, and disappeared after iron deficiency correction. Retinal hemorrhage and exudation can be seen in a small number of patients with severe anemia.

3. Common complications

Severe and persistent anemia can lead to anemic heart disease and even heart failure.

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