Blood cells are quite diverse. Each of them performs a specific role aimed at preserving and maintaining body functions. Platelets are responsible for protecting the body from blood loss.
It is especially important to determine the number of these cells in children, since they are more susceptible to injury, and blood loss with them can affect the body much more than in an adult. So what are platelets, and what is the norm for platelets in children?
What are these cells?
Platelets are cells that ensure the integrity of the walls of blood vessels. They are formed from a megakaryocyte - a giant cell devoid of a nucleus. The formation of platelets (the second name of platelets) occurs by detaching them from a giant cell.
About 70 percent of all formed cells circulate in the vessels, and 30 percent remain in the spleen. The destruction of these cells also occurs there.
Platelets do not have nuclei, and due to this they are not able to reproduce.
Their cytoplasm contains a certain amount of enzymes, as well as substances that promote the formation of blood clots,due to which these cells carry out their functions.
Platelets do not live for long - from 7 to 10 days, after which unused cells are destroyed by macrophages.
The norm of platelets in children is always somewhat higher than in adults. This is due to the active metabolism of the child's body. What are the normal values for the number of these cells?
Normal performance
How many of the determined blood cells should platelets be? The norm in children usually lies within the following limits:
- In newborns, platelet counts typically range from 100 to 42010⁹ cells per liter of blood.
- At the age of one year, the minimum number of platelets increases slightly - up to 150. The maximum, on the contrary, decreases to 350.
- After a year, the platelet index of a child is the same as that of an adult - 180-32010⁹ per liter of blood.
- At the age of five, a certain phenomenon is sometimes observed - platelets change (the norm in children of 5 years does not differ from adult indicators, however, the cells become more active, due to which the development of thrombopathies is observed). This phenomenon is explained by the second pediatric decussation. Due to the dominance of neutrophils, inflammation processes can be triggered with false activation of platelets.
It should be remembered that with a hardware blood test and with manual counting, the platelet rate in a child's blood may vary somewhat. Therefore, with automatic counting, the maximumnormal values of the plates are up to 500 in newborns and up to 400 in a one-year-old child.
Preference should still be given to manual counting: less likely to make a mistake and more to make a correct diagnosis.
How are they formed?
The formation of platelets occurs in the bone marrow. The ancestor of these cells is a megakaryocyte - a giant cell. It is located between endothelial cells and fibroblasts. Due to the influence of these cells from the outside, the particles of the megakaryocyte are separated (its cytoplasm passes between the surrounding cells and is thus laced).
Emerging into the bloodstream, platelets circulate through it until they reach the damaged area of the vessel (the presence of endothelial damage is important). Settling there, platelets trigger some humoral processes, as a result of which a fibrous skeleton is formed at the site of the lesion, on which new platelets settle. Thus, first a white and then a red thrombus is formed.
The process of formation of cells in the bone marrow occurs daily, which allows you to maintain their normal number. Any damage to the bone marrow contributes to a decrease or increase in the number of plates.
Changes in the number of cells
As you know, all indicators of the internal environment of the human body change under the influence of various reasons. An increase in the level of platelets is called thrombocytosis. It can be divided into primary and secondary. Primary thrombocytosis develops as a result ofdirect damage to the bone marrow. Secondary depends on comorbidities.
Reducing the level of platelets is called leukopenia. Like thrombocytosis, it is divided into primary and secondary.
It is necessary to understand how platelets vary in children. The norm (the table includes normal indicators and deviations according to age) can change in any direction and sometimes be regarded incorrectly. That is why it is extremely important to know the possible deviations from the norm in children for the correct diagnosis. the table looks like this.
| Indicator | Thrombocytopenia | Norma | Thrombocytosis |
| first 5 days of life | < 42010⁹ | 215-42010⁹ | >42010⁹ |
| 10-14 days | < 17510⁹ | 175-42010⁹ | >42010⁹ |
| 1 year | < 15010⁹ | 150-35010⁹ | >35010⁹ |
So why do the levels of these cells change? It is necessary to understand this problem in more detail.
Reasons for high platelets
Why can platelets increase? The norm in children may change due to the following reasons:
- Myeloproliferative diseases (usually tumor lesions of the bone marrow with an increase in its functional activity). An increase in the number of platelets occurs most often withparallel increase and other cells.
- Inflammatory diseases, usually of a chronic nature - rheumatoid joint disease (juvenile arthritis), tuberculosis.
- Bleeding. There is a functional overproduction of platelets to stop blood loss.
- Use of glucocorticosteroids. These hormones, when used for a long time (for example, with severe bronchial asthma), cause almost all natural processes to be disrupted, so thrombocytosis can occur.
Above normal platelets in a child can also be observed as a result of diseases of the blood system (for example, with erythremia).
Reduce platelets
As mentioned, the level of clotting cells may decrease. Why is this happening?
Platelets below the norm in a child are observed most often in blood diseases - aplastic anemia and leukemia. The number of cells of the immune system also decreases.
Hereditary diseases. These include Wiskott-Aldrich syndrome, Fanconi, histiocytosis. It is these diseases that lead to the fact that children have reduced platelets. The norm in children is almost never observed, the level of plates is always reduced.
Menstruation. They cause thrombopenia in girls who have recently had menarche. Before the cycle normalizes, there may be a significant decrease in the level of cells.
Heavy metal poisoning. Lead poisoning is most common (for example, it is knowna case where a child had this poisoning as a result of the evaporation of vapors from new wallpaper).
Features in children
Platelet counts usually normalize by one year, but during the neonatal period, the baby's blood system undergoes some changes.
When platelets are determined, the norm in children under one year old may vary somewhat. For example, during the first five hours of a baby's life, about 215 million platelets are observed in the blood. During the first five days, this number decreases, and by the end of day 5, their number stops at 175 million. It is on the 5th day that significant changes occur in the blood - the level of not only platelets, but also leukocytes changes (the so-called “pediatric scissors” - a cross of lymphocytes and neutrophils). From about the tenth day, the platelet count stabilizes - at least 100 million cells (100-42010⁹).
As they grow older, their number increases slightly and becomes equal to 180-32010⁹ for about a year.
How to identify platelets?
A blood test is used to determine the number of platelets. It can be carried out in any clinic or laboratory equipped with the necessary equipment.
When conducting an analysis, it is imperative to take into account the age of the child. It should be remembered that if platelets are determined, the norm in children under one year old, namely its lower limit, is quite low. You should only panic if the lower indicator is less than 100.
Indications for the determination of cells are prolonged bleeding oron the contrary, excessively rapid formation of blood clots.
As mentioned above, if platelets are determined, the norm in children may fluctuate slightly depending on the method of counting. If automated scoring is used, the upper limit of normal is slightly higher than with manual scoring. This is due to the fact that the device perceives even small blood clots as several blood clots, and a person, when counting, as one cell.
In addition to determining the number of cells, it is possible to evaluate their functional activity. For this, another study is assigned - a coagulogram. It can detect abnormalities in the work of the plates, even if the norm of platelets in the child's blood has been determined.
What is the danger of changing normal indicators?
Why is the level of blood clotting elements determined? Their definition is important in the following cases:
- Low cell levels increase the risk of bleeding. When an injury occurs, the likelihood of large blood loss increases significantly (and for a child, the loss of even a small amount of blood can be fatal). Usually, bruises on the skin even after light contact with it are the harbingers of a decrease in the level of cells. When they appear, be sure to take a platelet test.
- An increase in the level of cells threatens with increased thrombosis, which can adversely affect blood circulation in general (the likelihood of developing thrombosis and subsequent stroke increases,infarction or necrosis).
That is why it is extremely important to determine these blood elements.
