Number of platelets

Reference values ​​of platelet count( PLT) in the blood: newborns 1-10 days - 99-421x109 / l;older than 10 days and adults - 180-320x109 / l

[Nikushkin EV, Kryuchkova MI, 1998].

Platelets are a blood element with a diameter of 2-4 microns, which is a "fragment" of the cytoplasm of the megakaryocytes of the bone marrow. The life span of platelets is 7-10 days. Physiological fluctuations in the number of platelets in the blood during the day are up to 10%.In women during menstruation, the number of platelets may decrease by 25-50%.Platelets perform angiotrophic, adhesive-aggregation functions, participate in the processes of blood clotting and fibrinolysis, provide retraction of the blood clot. They are able to carry circulating immune complexes( CIC) on their membranes, to maintain vasospasm. In 80-85% of patients with hemorrhagic diathesis, disorders in the hemostasis system are caused by a decrease in the amount or a decrease in the functional activity of platelets.

An increase in the number of platelets in the blood( thrombocytosis) can be primary( the result of primary proliferation of megakaryocytes) and secondary, reactive, arising against a background of a disease.

Increased platelet counts in the blood of can cause the following diseases.

■ Primary thrombocytosis: essential thrombocythemia( platelet count may increase to 2000-4000x109 / L and more), erythremia, chronic myelogenous leukemia and myelofibrosis.

■ Secondary thrombocytosis: acute rheumatic fever, rheumatoid arthritis, tuberculosis, liver cirrhosis, ulcerative colitis, osteomyelitis, amyloidosis, acute bleeding, carcinoma, lymphogranulomatosis, lymphoma, condition after splenectomy( for 2 months or more), acute hemolysis, after operations(within 2 weeks).

Reduction in the number of platelets in the blood less than 180x109 / l( thrombocytopenia) is noted with oppression of megakaryocytopoiesis, platelet production disturbance. Thrombocytopenia can cause the following conditions and diseases.

■ Thrombocytopenia caused by reduced platelet formation( hematopoietic insufficiency).

□ Purchased:

- idiopathic hematopoiesis hypoplasia;

- viral infections( viral hepatitis, adenoviruses);

- intoxication( myelodepressive chemicals and preparations, some antibiotics, uremia, liver diseases) and ionizing ozuzuchenie;

- tumor diseases( acute leukemia, cancer metastases and sarcomas in the red bone marrow, myelofibrosis and osteomyelitis);

- megaloblastic anemia( deficiency of vitamin B12 and folic acid);

- night paroxysmal hemoglobinuria.

□ Hereditary:

- Fanconi syndrome;

- Wiskott-Aldrich syndrome;

- May-Heglin anomaly;

- Bernard-Soulier syndrome.

■ Thrombocytopenia caused by increased destruction of platelets.

□ Autoimmune - idiopathic( Werlhof disease) and secondary [with systemic lupus erythematosus( SLE), chronic hepatitis, chronic lymphocytic leukemia, etc.], in newborns due to penetration of maternal autoantibodies.

□ Isoimmune( neonatal, posttransfusion).

□ Hapten( hypersensitivity to certain drugs).

□ Associated with a viral infection.

□ Associated with mechanical damage of platelets: with prosthetics of heart valves, extracorporeal circulation;with nocturnal paroxysmal hemoglobinuria( Marciaf-you-Mikeli disease).

■ Thrombocytopenia caused by sequestration of platelets: sequestration in hemangioma, sequestration and destruction in the spleen( hyper-splenism in Gaucher disease, Felty's syndrome, sarcoidosis, lymphoma, spleen tuberculosis, myeloproliferative diseases with spleen-numiglia, etc.).

■ Thrombocytopenia caused by increased platelet consumption: disseminated intravascular coagulation( DVS) syndrome, thrombotic thrombocytopenic purpura, etc.

Number of platelets in the blood that need correction:

■ below 10-15x109 / l - in the absence of other bleeding risk factors;

■ below 20x109 / l - if there are other risk factors for bleeding;

■ below 50х109 / l - with surgical interventions or bleeding. An algorithm for diagnosing the causes of thrombocytopenia is presented in Fig.