The platelets (also called thrombocytes or PLT) they are corpuscular elements of the blood that are responsible for blocking the loss of blood in case of lesions of the vascular system through the process of hemostasis and coagulation.
What are platelets?
The platelets, having an average life of 10 days, are produced by the red bone marrow (just like the other corpuscular elements of the blood such as red blood cells and white blood cells), through the genesis of large cells with numerous nuclei inside, called megakaryocytes.
What are platelets used for?
In cases of blood loss, the megakaryocytes are activated, fragmenting and giving rise to platelets, which approach the point of bleeding, attaching themselves to both vessel wall, both between the plate and the plate, creating a platelet aggregation which is called "Platelet plug".
This is the first step of the coagulation process, which leads to stopping the bleeding and activating all the steps for restoring tissue continuity. When these corpuscles become old, they are phagocytosed and destroyed by macrophages present mainly in the spleen and liver.
The doctor may indicate the examination of platelets in various situations, such as for example the screening, diagnosis or control of pathologies that alter the normal values or function of platelets (diseases of the blood, of the bone marrow or coagulation disorders). Often these alterations do not give any sign of their presence, both when there is a lack of platelets, and when the concentration is increased.
When the cause of the alteration of this value is discovered, the doctor will know what to do to act directly against the predisposing pathology, using effective remedies that resolve the clinical picture even in a very short time.
Normal values of platelets and platelet parameters
What are the normal values of platelets? There platelet count (PLT) indicates the number of platelets for a unit volume of blood, ed normal values in adults they range from 150 to 450,000 units per microliter of blood, while in children this range ranges from 150 to 700,000 units per microliter of blood. A low PLT condition will occur for a platelet concentration below 150,000 units per microliter of blood.
Performing a corny blood count, we can evaluate some parameters related to these corpuscles: remember theMPV, the PDW and the PCT.
The platelet volume medium (or Mean Platelet Volume - MPV) expresses the average size of platelets in the blood examined. It is normally between 9.7 and 12.8 femtoliters (ie one billionth of a liter) and is used, together with all the other platelet parameters, to better frame blood pathologies. A high MPV value indicates that the body is increasing platelet synthesis, while the opposite situation will occur in the case of low MPV.
L'amplitude of platelet distribution (or Platelet Distribution Width - PDW) represents the variability of platelet sizes: a high PDW indicates that the volumes of these elements are very different from each other, while a low PDW indicates that the platelet volumes are more uniform between them. Normally the PDW must be between 9 and 14 fL, but it is a parameter that must be corrected according to the age and sex of the subject in question, as there are large variations in physiological values over the course of life.
L' hematocrit platelet or plateletcrit (PCT) indicates how much blood volume is occupied by the platelet mass. Normally, the reference interval is between 0.20 and 0.36% and is calculated, together with the other parameters described above, to detect alterations in the amount of platelets circulating in the blood. A low PCT value will be associated with a condition of thrombocytopenia, while a high PCT value is related to a thrombocytosis.
High platelets or platelets
The finding of high platelets in the blood is called platelets. There platelet disease it is a condition in which an adult subject finds himself having a platelet count in the blood higher than 450,000 units per microliter (or mm3) of blood. Instead they consider themselves values of high platelets in children if the concentration of these elements exceeds 700,000 units per microliter of blood.
Causes of high platelets
The causes of high platelets can be divided into:
- primary (or essential) causes, ie related to diseases derived from a proliferation of hematopoietic cells (called myeloproliferative diseases);
- secondary causes (from the most frequent finding), i.e. deriving from a known condition.
The myeloproliferative pathologies more involved in the genesis of an increase in platelets of primary type are:
- polycythemia vera (an uncontrolled proliferation of blood stem cells);
- primary idiopathic myelofibrosis (abnormal proliferation of blood cells due to damage to the DNA of a blood stem cell);
- chronic myeloid leukemia (linked to an increase in the genesis of a class of white blood cells, the neutrophilic granulocytes, caused by a chromosomal alteration);
- acquired idiopathic sideroblastic anemia (or refractory anemia with ring sideroblasts);
- essential thrombocytosis (platelet proliferation from stem cells without any definite reason), to be considered as a last resort, after first excluding the above diseases.
For the secondary platelet diseases there are numerous subclassifications. The most used is related to the duration of platelet disease, which can be acute or chronic.
The main ones acute causes of high platelets I'm:
- situations of high physical stress (intense physical exercise, great fear ...);
- intravenous administration of adrenaline;
- situations of hypoxia;
- following a surgical operation;
- following a birth;
- acute bleeding or hemolysis;
- following thrombocytopenia (or rebound thrombocytosis), linked to conditions such as autoimmune diseases, infections, therapy for vitamin B12 and / or folic acid deficiencies causing megaloblastic anemias, administration of chemotherapy etc ...;
- in the newborn, in case of maternal abuse of narcotics.
The main chronic causes of platelet disease I'm:
- iron deficiency and iron deficiency anemia, that is linked to chronic blood loss (most frequent cause) or to a deficiency of this element in the blood;
- chronic hemolytic anemias;
- chronic infectious diseases, such as tuberculosis or syphilis;
- chronic inflammatory bowel disease (such as Crohn's disease or ulcerative colitis);
- neoplasms, particularly those with kidney or lungs;
- asplenia (functional insufficiency of the spleen, which is no longer able to perform its duties);
- hyposplenia (decrease in the volume of the spleen);
- splenectomy (surgical removal of the spleen).
Symptoms of high platelets
From the symptomatic point of view, this condition often goes on asymptomatic in most patients. However, there are some symptoms of high platelets that can be assessed as real "alarm bells". Among others, we must remember:
- increased blood pressure (which can lead to severe headaches, dizziness and episodes of tachycardia);
- severe itching;
- abdominal pain;
- enlarged spleen or splenomegaly;
- weight loss and poor appetite;
- low blood iron concentration;
- venous and arterial thrombosis (platelet disease is one of the risk factors that predispose to the genesis of these conditions).
High platelets in pregnancy
The finding of high platelets in pregnancy, combined with low hemoglobin values is a possible risk factor
- miscarriages, particularly in the first ten weeks, possibly due to thrombosis of the placenta;
- intrauterine growth retardation;
- premature births;
- fetal intrauterine death.
Low platelets or thrombocytopenia
There thrombocytopenia, instead, it is a condition that results from the presence of a number of low platelets in blood circulating, less than 150,000 units per microliter of blood.
Causes of low platelets
The causes of thrombocytopenia are numerous and for this reason a classification has been proposed that divides them into 5 groups, based on the time of platelet life in which the pathological alteration occurs:
- From less production of megakaryocytes. This group includes pathologies such as medullary aplasia, primary medullary neoplasms or secondary neoplastic infiltrations of the bone marrow (marrow metastases). In the case of medullary aplasia, low platelet values are found together with low red blood cell and white blood cell values;
- From less platelet production. In this group we find deficiencies of B12 or folic acid (mainly due to dietary deficiency), myelodysplastic syndromes, autoimmune diseases (SLE, anti-phospholipid antibody syndrome).
- From greater platelet destruction. In this group we can distinguish the causes of increased destruction in immune (idiopathic thrombocytopenic purpura or Werlof's disease, associated with autoimmune diseases, associated with lymphoproliferative diseases, associated with the use of drugs or associated with the presence of isoantibodies) and in non-immune (intravascular prostheses, abnormalities of the blood vessel wall or presence of fibrin thrombi). Interesting to note is the presence of low platelet values in pregnancy in patients with idiopathic thrombocytopenic purpura: this pathology, in addition to a deficiency in medullary production of megakaryocytes, can cause symptoms especially in the third trimester of pregnancy, but often runs asymptomatic without using any specific care;
- From increased consumption of platelets. The most frequent cause is related to CID (or Disseminated Intravascular Coagulation), in which we have an abnormal activation of the coagulation cascade with the formation of intravascular thrombi and platelet aggregates in the face of a condition of thrombocytopenia and a tendency to form hemorrhages serious even for minor trauma. In addition to this pathology, we find the thrombotic thrombocytopenic purpura (PTT or Moschcowitz syndrome) and the hemolytic-uremic syndrome.
- From platelet seizure. The most frequent sites of platelet sequestration are at the splenic level, in case of splenomegaly (enlarged spleen) or in hemangiomas (vascular tumors that can also be large, or small but in large numbers). An enlarged spleen is common in people with liver cirrhosis and in those suffering from hematological diseases such as leukemias or lymphomas.
Symptoms of low platelets
What are the main symptoms of thrombocytopenia? The presence of symptoms basically depends on two factors:
- platelet count. Symptoms are scarce or even absent up to platelet values that reach 50,000 units per microliter of blood: if the thrombocytopenia falls below this value, it will be easier to see signs of a decrease in platelet concentration.
- platelet function. It is not uncommon to find a normal plasma concentration of platelets in the face of signs and symptoms suggestive of thrombocytopenia. This happens because the platelets present, for some reason, do not function as they should and therefore, despite being in the correct number, they cannot perform their functions.
The fundamental element of the symptoms of low platelets is the presence of hemorrhage, which, depending on the affected vessel, can give rise to:
- nasal epistaxis, the classic nosebleed
- bruising or bruising, especially in case of trauma
- gum bleeding or gingivorrhagia,
- menorrhagia, i.e. heavy menstrual flow or hypermenorrhea
- metrorraggie, i.e. uterine / vaginal blood loss outside the menstrual period
- gastrointestinal bleeding or haemorrhage
- retroperitoneal or muscle bleeding (such as the dreaded retroperitoneal hematoma, which remains asymptomatic until it is very extensive)
In case of bleeding we will have common symptoms such as weakness, tachycardia, hypotension, skin and nail pallor, in addition to symptoms related to the affected body part.
In cases of extreme thrombocytopenia, they will also be observed brain hemorrhages, clinical conditions with poor prognosis. Obviously, the lower the value of thrombocytopenia, the more worrying the degree of bleeding will be, the easier it is to observe the genesis of spontaneous bleeding.
Other symptoms of thrombocytopenia are the feeling of tiredness and increased fatigue, even for small efforts.
How to increase platelets?
How to raise platelets? First of all, there are no magic foods or remedies that can increase platelets. The best way to increase the values is to understand the cause of their reduction, then contacting the attending physician and carrying out the appropriate blood and instrumental tests when required. In some cases, it may be enough to stop a particular drug that the doctor will have identified as responsible. In other cases, low platelets cannot be increased as they may be due to non-modifiable pathologies and conditions.
In any case, a healthy lifestyle, avoiding alcoholic beverages and harmful agents, certainly reduces the probability of developing neoplastic pathologies or chronic diseases which, secondarily, can lead to thrombocytopenia.Tags: Coagulation Hematology Laboratory medicine Blood