Thrombocytopenia is a lack or low level of blood platelets (platelets). These colorless blood cells are of great importance for blood clotting. Pronounced thrombocytopenia can be life-threatening, because it causes bleeding and spontaneous hemorrhage to the internal organs.
Causes of autoimmune thrombocytopenia
The causes of thrombocytopenia are very diverse. Lack of platelets can occur because of immunity problems with blood transfusion, which is incompatible with group membership, or when foreign antigen enters the body, for example, a virus. But most often in the human body, autoimmune thrombocytopenia develops. This is a condition in which the immune system does not "know" its healthy platelet, which leads to the development of antibodies to eliminate the "alien". If such thrombocytopenia accompanies another ailment, then it is called secondary. Its causes are various pathologies:
- collagenoses (dermatomyositis, systemic lupus erythematosus or scleroderma );
- chronic and acute leukemia (Waldenstrom macroglobulinemia, myeloma);
- some kidney diseases and chronic hepatitis.
If autoimmune thrombocytopenia manifests itself as an isolated disease, then it is called Verlhof's disease, as well as essential or idiopathic thrombocytopenia. The causes of this ailment are not exactly established. Among the factors preceding its development, there are viral and bacterial infections, surgical operations, vaccinations, injuries and the introduction of gamma globulin. In 45% of cases, essential thrombocytopenia occurs spontaneously without any reason.
Causes of productive thrombocytopenia
Productive thrombocytopenia occurs in the body, when the bone marrow can not put platelets in the amount in which they are necessary for a normal circuit. The causes of this thrombocytopenia in adults are:
- aplastic anemia ;
- TAP-syndrome;
- myelodysplastic syndrome;
- myelosclerosis;
- metastases of some tumors in the bone marrow;
- the action of chemicals (for example, benzene).
In addition, productive thrombocytopenia appears as a result of acute leukemia, when there is a deep tumor transformation of hematopoiesis, with alcoholism and various infections (viremia, miliary tuberculosis, bacteremia). Suffer from the lack of platelets and those who have a deficiency of vitamin B12 and folic acid. Possible development of thrombocytopenia and against radiation therapy or exposure to ionizing radiation.
Causes of drug thrombocytopenia
With drug thrombocytopenia, antibodies are produced against a foreign antigen-drug that is fixed on the surface of platelets, or when the antigenic structure of platelets changes. In most cases, the causes of this type of thrombocytopenia are the following drugs:
1. Sedatives:
- Meprobamate;
- Phenobarbital;
- Sedormid;
- allyl isopropylbarbituric acid.
2. Alkaloids:
- Quinidine;
- Quinine.
- Antibiotics;
- Oxytetracycline;
- Streptomycin;
- Chloramphenicol;
- Ristocetin.
3. Antibacterial sulfonamides:
- Sulfidiazine;
- Sulfamethazine.
4. Other medicines:
- Dinitrophenol;
- potassium iodide;
- Digitoxin;
- Carbamazepine.
Causes of thrombocytopenia in HIV patients
Thrombocytopenia can manifest in HIV-infected people. There are two reasons for provoking this condition in patients:
- First, it is that HIV strikes megakaryocytes, resulting in a shortage of platelets.
- Secondly, drugs that help fight infection often damage the red bone marrow of a person.