Sideroblastic anemias in children

Anemias associated with impaired synthesis or utilization of porphyrins (sideroachrestic, sideroblastic anemias) are a heterogeneous group of diseases, hereditary and acquired, associated with impaired activity of enzymes involved in the synthesis of porphyrins and heme. The term "sideroachrestic anemia" was introduced by Heylmeyer (1957). In sideroachrestic anemias, the level of iron in the blood serum is elevated. In the bone marrow, ring-shaped sideroblasts are found - nucleated erythrocytes with a perinuclear rim consisting of coarse hemosiderin granules and representing mitochondria filled with iron.

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Causes of sideroachrestic anemia

Hereditary forms

They are transmitted in a recessive, X-linked manner (males are affected) or an autosomal dominant manner (both males and females are affected).

The metabolic block may be at the stage of formation of delta-aminolevulinic acid from glycine and succinyl CoA. This reaction requires pyridoxal phosphate, an active coenzyme of pyridoxine and aminolevulinic acid synthetase.

Acquired forms

Acquired forms of anemia associated with impaired porphyrin synthesis may be caused by lead poisoning.

Household lead intoxication is quite common in pediatric practice. It occurs when eating food that has been stored in tinned or home-made clay pottery with glaze. Lead poisoning is most often caused by the ingestion of lead-containing paints, plaster, and other materials saturated with lead dyes (newspapers, gypsum, crushed stone; lead content exceeds 0.06%), as well as household dust and soil particles (lead content 500 mg/kg). Lead enters the atmosphere not only through inhalation; most often it precipitates and enters the body with dust and soil particles. In infants, lead poisoning occurs when contaminated water is used to prepare infant formula. Intoxication can result from failure to observe the necessary precautions when smelting lead at home.

Causes of sideroblastic anemia

Diagnosis of sideroachrestic anemias

The diagnosis of hereditary forms of anemia is confirmed by studying the content of porphyrins in erythrocytes. It has been established that in hereditary forms of sideroachrestic anemia, the content of erythrocyte protoporphyrin is reduced. The content of erythrocyte coproporphyrin can be both increased and decreased. Normally, the average level of erythrocyte protoporphyrin in whole blood is 18 μg%, and the upper limit in the absence of anemia is 35 μg%. To study the content of iron reserves and confirm hemosiderosis, the desferal test is used. After intramuscular administration of 500 mg of desferal, 0.6-1.2 mg of iron per day is normally excreted in the urine, and in patients with sideroblastic anemia - 5-10 mg / day.

To diagnose lead poisoning, the level of lead in venous blood is determined; the level of erythrocyte protoporphyrin in whole blood - a level above 100 μg%, as a rule, indicates the toxic effect of lead.

Diagnosis of sideroblastic anemia

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Treatment of sideroachrestic anemias

Treatment of patients with hereditary sideroachrestic anemia

1. Vitamin B _{6 in large doses - 4-8 ml of 5% solution per day intramuscularly. If there is no effect, the coenzyme of vitamin B12} - pyridoxal phosphate is indicated. The daily dose of the drug is 80-120 mg when taken orally.
2. Desferal (to bind and remove iron from the body) - 10 mg/kg/day in monthly courses 3-6 times a year.

Treatment of sideroblastic anemias

Prevention of lead poisoning

To avoid lead poisoning, precautions should be taken when renovating old homes, such as temporarily relocating children. Burning and burying lead paint is especially dangerous; it should be scraped off or removed chemically. Monitoring the condition of living spaces and tightening sanitary and building codes reduces the incidence of poisoning.