What provokes iron deficiency anemia?

There are more than 10 known types of iron metabolism disorders that lead to the development of iron deficiency anemia. The most important are:

• iron deficiency in food, which is important in the development of iron deficiency conditions in children from early childhood to adolescence, as well as in adults and the elderly;
• impaired iron absorption in the duodenum and upper small intestine as a result of inflammation, allergic edema of the mucous membrane, giardiasis, Helicobacter jejuni infection, and bleeding;
• disruption of the Fe ³⁺ -»Fe ²⁺ transition due to a deficiency of androgens, ascorbic acid, atrophic gastritis, leading to insufficient formation of gastroferrin.
• initially low iron levels in the body;
• insufficient dietary intake;
• increased need;
• discrepancy between iron intake and losses;
• iron transport disorder.

Any one of these factors or a combination of them may be important in each patient.

It is advisable to highlight the risk factors for iron deficiency on the part of the mother and child and the causes of iron deficiency anemia in children of different ages. In young children, predominate factors of prenatal iron deficiency and factors causing a discrepancy between the need and supply of iron in the body. In older children, conditions leading to increased (pathological) blood loss are in first place.

Risk factors and causes of iron deficiency in women and children of different ages

Risk factors for developing iron deficiency
Mother:	The child has:
more than 5 pregnancies; interval between pregnancies less than 3 years; multiple pregnancy; gestosis; IDA in pregnant women; heavy menstruation; chronic infections; sports activities; donation; vegetarianism; occupational hazard	intensive growth in early and pubertal age; rickets; frequent infections, acute intestinal infections, acute respiratory viral infections; dysbacteriosis; menstrual cycle disorders; sports activities; vegetarianism
Causes of Iron Deficiency
Young children:	Older children:
Prenatal Fe deficiency factors: placenta previa, placental abruption; rupture of the umbilical cord; fetofetal and fetoplacental transfusions; prematurity, high birth weight; Factors that cause insufficient Fe intake in the body: feeding defects; malabsorption syndrome, cow's milk intolerance, recurrent acute intestinal infections; Factors causing blood loss: gastrointestinal tract anomalies; tumors; telangiectasia; Impaired iron transport: hypo- and atransferrinemia	Factors causing blood loss: gastrointestinal pathology (mucosal duplication, polyposis, diverticulosis, varicose veins, erosive gastritis, peptic ulcer, ulcerative necrotic colitis, esophageal hernia, tumors, telangiectasia; helminthiases: trichuriasis, hookworm disease, ascariasis; juvenile bleeding; hemorrhagic diathesis, thrombocytopathy, thrombocytopenia, coagulopathy; pulmonary hemosiderosis; endometriosis; glomus tumors; frequent blood sampling for research (iatrogenic blood loss). Endocrine diseases hypothyroidism; ovarian dysfunction. Hematuria:. Tuberculosis; Malabsorption syndrome, gastric and small bowel resection Impaired iron transport, hypo- and atransferrinemia Extracorporeal methods of treatment. Alimentary deficiency.

The main causes of iron deficiency anemia in children and adolescents

• alimentary Iron deficiency due to unbalanced diet;
• iron deficiency at birth;
• increased need of the body for iron due to the child’s rapid growth;
• iron losses exceeding physiological levels.

I. Ya. Kon (2001) cites 3 main alimentary-dependent factors in the development of iron deficiency in children:

• reduced iron intake from food;
• decreased absorption;
• increased losses.

The following reasons for reduced iron intake with food are considered:

• lack of breastfeeding;
• the use of partially adapted and non-adapted milk formulas and non-iron-fortified cereals in the nutrition of young children;
• late introduction of complementary foods;
• reduced intake of vitamin C, etc.

Reduced iron absorption is caused by the use of large amounts of plant fibers, excess protein, calcium, and polyphenols in the diet. Increased iron losses are possible with the early introduction of whole milk and kefir into the child's diet, which leads to the appearance of diapedetic bleeding from the stomach and small intestine and hemoglobin losses through excretion with feces.

To prevent iron deficiency, work to increase the prevalence of breastfeeding remains important. Breast milk contains iron with the highest bioavailability - 50%, which has no analogues.

In the human diet, there are heme and non-heme foods; non-heme foods predominate (90%), heme foods make up about 10%. The degree of iron absorption from these types of foods also varies. The absorption of iron from rice, corn, soy, beans, kidney beans, spinach, flour is 1-7% of its content in the product. The absorption of iron from meat products is from 18-20 to 30%.

Long-term nutrition of plant-based products - suppliers of hard-to-digest non-heme iron - and refusal of meat products rich in easily digestible heme iron can lead to iron deficiency anemia. This is confirmed by examination of vegetarians. "Civilized" vegetarians of Western countries necessarily use multivitamins, microelements, including iron preparations against the background of a plant-based diet, which allows them to have a normal hemoglobin level.

Causes of iron deficiency anemia in pregnant women

Anemia in pregnant women is usually caused by 2 reasons: a negative iron balance in the body and its insufficient intake. Iron deficiency in the body of a pregnant woman is dangerous due to numerous risks for herself and the fetus, in particular:

• placental insufficiency;
• intrauterine fetal death;
• miscarriages;
• premature birth;
• low birth weight of the baby;
• preeclampsia;
• pyelonephritis;
• postpartum infections;
• bleeding.

The pregnant woman's need for iron increases so much that it cannot be covered by a normal diet, even if iron absorption increases several times. The total iron expenditure of a pregnant woman consists of:

• additional maternal red blood cells - 450 mg;
• fetal tissue, placenta and umbilical cord - 360 mg;
• blood loss during childbirth - 200-250 mg;
• daily loss through the gastrointestinal tract and sweat - 1 mg;
• losses with milk during breastfeeding - 1 mg.

Total iron losses amount to more than 1000 mg.

The criteria for anemia in pregnant women are considered to be a decrease in hemoglobin concentration to less than 110 g/l in the first and third trimesters of pregnancy and less than 105 g/l in the fourth trimester.

As is known, the concentration of hemoglobin in 30% of women after childbirth is below 100 g/l, and in 10% of women - below 80 g/l, which corresponds to moderate anemia, requiring treatment and worsening due to the lactation period. Causes of postpartum anemia in women:

• depletion of iron stores in the depot during pregnancy;
• blood loss during childbirth.

Blood loss during physiological childbirth is 400-500 ml (200-250 mg of iron), and in case of multiple pregnancy or cesarean section it increases to 900 ml (450 mg of iron). Traditional methods of treating postpartum anemia:

• transfusion of red blood cells in severe cases requiring emergency treatment;
• use of oral iron preparations in cases of mild anemia.

The use of intravenous iron preparations in the treatment of postpartum anemia has proven to be an effective and rapid treatment method. This is extremely important due to the fact that women are discharged from the maternity hospital early and they have a lactation period ahead of them, which requires an additional minimum of 1 mg of iron per day. As the results of the studies have shown, the use of the drug Venofer [iron (III) hydroxide sucrose complex; 3 intravenous injections of 200 mg during the week] leads to a revolutionary result: in a group of 30 women, an increase in the average hemoglobin concentration from 70.7 to 109.3 g/l was noted. Thus, the transition of severe anemia to mild in record time was demonstrated. Such treatment serves as an alternative to blood transfusions.

Chronic posthemorrhagic anemia, associated with a long-term loss of a small volume of blood, is also classified as iron deficiency anemia and is treated according to the principles of treating iron deficiency anemia. When treating chronic posthemorrhagic anemia, it is first necessary to find the source of blood loss and eliminate it. For male patients, losses from the gastrointestinal tract are more typical, caused by:

• ulcerative bleeding;
• colon polyps;
• nonspecific ulcerative colitis;
• intestinal angiomatosis;
• the presence of Meckel's diverticulum;
• tumors of the stomach and intestines (in adults);
• bleeding from hemorrhoids (in adults).

In female patients, the most common bleeding is associated with juvenile uterine bleeding in girls of pubertal age and prolonged and heavy menstruation, observed in 12-15% of women of reproductive age. Loss of hemoglobin from the gastrointestinal tract ranks second in women.

Donors who frequently donate blood (regular donors) are at risk of developing iron deficiency conditions or already have iron deficiency anemia. Overcoming iron deficiency in donors is possible with the help of:

• breaks in blood donation (at least 3 months);
• adequate nutrition;
• prescribing iron preparations for oral administration.

The only drawback of these recommendations is the need for their long-term implementation. Rapid overcoming of iron deficiency in regular donors is fundamentally possible by administering intravenous iron preparations, for example, by using the drug venofer registered in our country. The following justifications are available for this:

• venous access for blood sampling is ensured;
• the volume of blood loss is known;
• The amount of iron loss from the body is calculated based on the volume of donated blood (a one-time exfusion of 500 ml of whole blood results in a loss of 250 mg of iron).

At the same time, the cost of whole blood and its components increases, but it is necessary, first of all, to take into account the donor's well-being, the decrease in his quality of life during the period of overcoming iron deficiency anemia. It is quite possible that the use of intravenous iron preparations will allow donors to donate blood more often, which is important given the existing donor shortage.

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Stages of iron deficiency development

Prelatent iron deficiency is characterized by decreased iron stores, decreased hemosiderin in bone marrow macrophages, increased absorption of radioactive iron from the gastrointestinal tract, and the absence of anemia and changes in serum iron metabolism.

Latent iron deficiency: along with depletion of the depot, the transferrin saturation coefficient decreases, and the level of protoporphyrins in erythrocytes increases.

Overt iron deficiency anemia: in addition to the above signs, clinical manifestations of iron deficiency are observed.