Reduced platelets in the blood
Human blood is a unique liquid tissue that carries many functions: it transfers into the tissues of the oxygen and picks up carbon dioxide, nutrients performs a protective function and protects the body from its own losses in case of bleeding. That was the function of platelets – platelets. In the case of reduction in their number occurs thrombocytopenia. What it shows, what are the causes and what is dangerous?
A condition in which reduced blood platelets you don’t always need to be considered as a manifestation of the disease. There are situations in which there is a temporary reduction in their number in peripheral blood. This can happen for example during pregnancy. This thrombocytopenia is considered to be physiological. What number of platelets can be considered a cause for concern, and when to see the doctor?
A little about platelets
Platelets, or plate, Bizzozero (plt in the analysis, Platelet count – flat, or discoid) are small cells without nuclei, related to formed elements of the blood, most numerous after the red blood cells. Their function is involved in blood clotting or hemostasis. They are formed in red bone marrow, and their precursors are giant megakaryocytes.
If necessary, caused by bleeding, platelets nearby, form outgrowths clumped together and the damaged vascular wall, turning from flat plates of marbles. And due to the complex cascade of biochemical reactions stop the bleeding. Thus, they are involved in platelet hemostasis.
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Functional characteristics, talking about the usefulness and maturity of platelets, is the average volume of platelets. The higher it is, the less Mature cells go into the blood from the bone marrow. The distribution of erythrocyte volume perform special laboratory apparatus analyzers. The norm volume of a single platelet is considered to be 7 – 11 FL (femtolitre), that is, from seven to eleven quadrillion fractions of a liter. This indicator in an automated blood test is coded with the abbreviation MPV (medium platelet volume – the average volume of a platelet).
This is a very small value. If proportionally increase one platelet to such proportions that it will occupy the volume of one drop of water (0.1 ml), one drop is the volume of 1000 cubic meters, i.e., is a cube with sides of 10 meters!
As can be seen, the width of the distribution of platelet volume is small, it is necessary to efficiently create a strong network in the case of injury.
What is thrombocytopenia?
Thrombocytopenia is called the absolute decrease in platelet count below 150 thousand cells in 1 microliter. The upper limit of normal is 400 thousand/µl.
Thrombocytopenia and other abnormalities in the cellular composition of the blood, is absolute and relative. Relative thrombocytopenia in the amount of blood revealed a decrease in their number for the reason that increased content of other cells «to the detriment» of the platelets. Or, for example, thrombocytopenia may occur after massive introduction of intravenous fluid, when the blood is «diluted» and the number of platelets are reduced by hemodilution (dilution) of the blood. And the absolute thrombocytopenia is detected on the background of normal indicators of the volume and cellular composition.
As a rule, pronounced clinical signs occur if the platelet count is below normal even tripled – their number is less than 50 thousand/µl. Symptoms of thrombocytopenia are summarized from a variety of hemostatic disorders such as:
- intradermal and subcutaneous bleeding from minor injuries;
- bleeding gums;
- heavy and prolonged periods (menorrhagia);
In addition to these relatively innocuous symptoms can be a condition that really life threatening, for example, massive gastric bleeding gastric ulcer (in the case of erosion of a major vessel). In chronic alcoholism and frequent thirst vomiting may develop the syndrome Mallory-Weiss syndrome, in which bleeding occurs from multiple small submucosal tearing of the wall of the gastric cardia. Bleeding from varicose veins of the esophagus in severe thrombocytopenia is often caused by hemorrhagic shock and may lead to death, especially in the elderly and on the background of severe anemia.
Physiological causes of thrombocytopenia
On the basis of clinical data and analysis results, the physician should identify the causes of thrombocytopenia in the blood and begin the treatment. We can immediately note the physiological causes, with which there are low platelets:
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- Pregnancy. During pregnancy the reason for the thrombocytopenia is the increase in blood volume (due to the fetus and fetoplacental blood flow), as well as shortening the lifetime of the platelets.
- Abundant and painful periods that often happen in women with unstable menstrual cycle.
Pathological causes of thrombocytopenia
All the other reasons that meet reduced platelets in the blood of the adult and the child, are the cause of various diseases. The most common are the following:
- congenital thrombocytopenia associated with abnormalities of their synthesis in red bone marrow: Fanconi syndrome, Wiskott-Aldrich syndrome;
- idiopathic thrombocytopenic purpura (a more detailed description of the disease is presented in a separate article);
- drug thrombocytopenia that often occur under the influence of cytostatics (Cyclophosphamide, Methotrexate);
- autoimmune disease: the platelet count is significantly reduced in collagen diseases, and systemic lupus erythematosus;
- infectious diseases and their consequences: typhus, malaria, toxoplasmosis
- enlargement of the spleen – splenomegaly, destroying blood cells, including platelets;
- various options of aplastic anemia (toxic due to radiation sickness);
- malignant neoplasms of blood-forming organs and metastases of tumors in red bone marrow, leukemias;
- congestive heart failure;
- megaloblastic anemia, characterized by the release into the blood of immature and not ready to «work» forms of thrombocytes;
- disseminated intravascular coagulation occurring hypercoagulation and platelet depletion of the germ;
In addition to these reasons for low platelet levels may result in use of substandard stents, vascular prostheses and artificial heart valves. If the material from which made these valves will not be «perfect» fit for the passage through it of the flow of blood without turbulence and turbulence, the platelets will simply collapse in the danger zone along with other blood cells. Along with thrombocytopenia possible to change the internal structure and functions of platelets. These States are called thrombocytopathy, and they will be discussed next time.