Idiopathic thrombocytopenic purpura (ITP) is a disease characterized by the destruction of platelets, which are the blood cells responsible for the first stages of blood clotting. It is not surprising, therefore, that one of the most common clinical manifestations of ITP is bleeding.
Before we speak of the disease properly, let us understand some concepts.
Platelets, also called thrombocytes, are blood cells produced in the bone marrow. A normal person has between 150,000 and 400,000 platelets per milliliter of blood. The role of platelets is to start the coagulation process. Every time we have a bleeding injury, platelets are the first components of the coagulation cascade to reach the site. They group together to form a kind of stopper to staunch bleeding quickly, giving the body time to repair the injury without further blood loss.
When we have a fall in the number of platelets (thrombocytes) we call thrombocytopenia. Therefore, the term thrombocytopenia of ITP indicates that one of the manifestations of the disease is the low platelet count.
When we have fewer platelets we are more exposed to bleeding. Purple is the name given to small purple patches on the skin caused by blood loss. In people with normal platelets, minor skin traumas are quickly controlled to prevent bleeding. In people with thrombocytopenia, there is a greater delay in the control of blood loss and this ends by overflowing to the skin. As our skin layer is slightly transparent it is possible to notice purple spots, which are nothing more than blood under the skin.
Unlike people with normal platelets, who need strong traumas to develop purple spots, the thrombocytopenic patient has several of these purplish lesions without even remembering to have knocked somewhere.
Small purples, such as dots, are called petechiae. The big purple spots are called bruise.
The term idiopathic means that there is no known cause. In fact, it is known that PTI is an autoimmune disease, that is, our body improperly produces antibodies against our own platelets. What is not known is why our body starts to recognize the platelets as something strange and starts to fight them.
The PTI affects both children and adults, but in the former it is usually an acute illness, started after a viral infection, and often with spontaneous resolution, without the need for specific treatment. In adults, it is a more chronic disease, sometimes requiring drug treatment. In adults, ITP can be a manifestation of another disease such as HIV, lupus or leukemias.
In children it usually occurs between 2 and 10 years. In adults, the incidence is higher between 20 and 40 years.
The clinical picture depends basically on the degree of reduction of platelets. Generally, values greater than 50,000 platelets per milliliter of blood do not cause symptoms. Below 50,000 there may be purples and petechiae. Below 30,000 bleeding risks begin to appear, which increase significantly when platelets are below 10,000 per ml. Children with ITP have a lower rate of spontaneous bleeding than adults, often tolerating platelets as low as 10,000 / ml.
In addition to purpura, the patient with idiopathic thrombocytopenic purpura may also have other signs of low platelets such as bleeding gums, mouth, nose, and, more rarely, blood loss in the stool and urine, as well as a coagulate the blood in small bruises.
There is no definitive examination for the diagnosis of ITP. This is done by counting platelets and after discarding other diseases that cause thrombocytopenia, such as cirrhosis, use of some drugs such as heparin or sulfa, preeclampsia.
The patient's blood count is normal except for the presence of thrombocytopenia itself.
As more than 80% of children spontaneously recover from ITP, drug treatment in this group is usually indicated only when there is severe thrombocytopenia or bleeding that puts the patient's life at risk. In general, no treatment is required when platelet levels are above 30,000 / ml. In patients with platelets below 30,000 / ml, indication of treatment or not should be individualized and evaluated on a case-by-case basis.
In most cases only preventive measures are necessary. The main ones are to avoid sports activities or any other that may be traumas or impact. It is also important to avoid drugs that may worsen platelet function, namely aspirin and anti-inflammatories.
The main drugs used in cases of severe ITP are steroids, usually prednisone or dexamethasone, and intravenous immunoglobulin.
Transfusion of platelets is only indicated in cases of imminent risk of death, since they will have a very short life, since they will be destroyed together with the patient's natural platelets. There is no point in supplying platelets until the destruction process has been interrupted.
About 20% of children with idiopathic thrombocytopenic purpura do not show improvement even after 6 months of evolution, behaving similarly to adult ITP.
In severe cases of ITP that do not respond to drug treatment or remain active for more than 12 months, splenectomy (spleen removal) can be used to control the disease.
B. ITP in adults
As with children, only drug treatment is indicated in adults with very low platelet counts or at risk of severe bleeding. Patients with platelets above 50,000 / ml need only frequent follow-up.
The treatment is similar to that of children, but in adult patients complete resolution of the disease is not expected, with the goal of only preventing very large falls in platelets.
Removal of the spleen may be indicated in severe cases lasting more than 6 weeks.
