A púrpura trombocitopênica trombótica, ou PTT, é uma doença hematológica rara, porém fatal, que é caracterizada pela formação de pequenos trombos nos vasos sanguíneos e é mais comum em pessoas entre 20 e 40 anos.
In PTT, there is a marked decrease in the number of platelets, in addition to fever and, in most cases, neurological disorders due to changes in blood flow to the brain due to clots.
- The diagnosis of PTT is made by the hematologist or the family doctor based on the symptoms and the result of the complete blood formula and blood smear and treatment should be initiated soon after.
- As the disease is fatal in approximately 95% of cases if left untreated.
Thrombotic thrombocytopenic purpura is mainly caused by the deficiency or genetic alteration of an enzyme, ADAMTS 13, which is responsible for reducing von Willebrand factor molecules and promoting their function. Von Willebrand factor is present in platelets and is responsible for promoting platelet adhesion to the endothelium, reducing and stopping bleeding.
Therefore, in the absence of the ADAMTS 13 enzyme, the von Willebrand factor molecules remain bulky and the blood stagnation process is affected and there is an increased risk of clotting.
Thus, TTP can have hereditary causes, which correspond to a deficiency of ADAMTS 13, or acquired, which are those that lead to a decrease in the number of platelets, such as the use of immunosuppressive or chemotherapeutic or antiplatelet drugs, infections. , nutritional deficiencies or autoimmune diseases, for example.
TTP generally has nonspecific symptoms, but it is common for patients with suspected TTP to have at least 3 of the following characteristics:
It is also common for patients with suspected PTT to experience symptoms of thrombocytopenia, such as purple or reddish spots on the skin, bleeding of gums or nose, as well as difficult control of bleeding from small wounds. Learn about the other symptoms of thrombocytopenia.
Kidney and neurological disorders are the main complications of TTP and occur when small thrombi obstruct blood flow to the kidneys and brain, which can lead to kidney failure and stroke, for example. To avoid complications, it is important that as soon as the first signs appear, a general practitioner or hematologist is consulted so that diagnosis and treatment can begin.
The diagnosis of thrombotic thrombocytopenic purpura is made based on the symptoms that the person presents, in addition to the result of the complete blood count, in which a decrease in the number of platelets, called thrombocytopenia, is observed, in addition to being observed. in blood smear platelet aggregation, which is when platelets come together, in addition to schizocytes, which are fragments of red blood cells because red blood cells pass through blood vessels that are blocked by small vessels.
Other tests may also be ordered to aid in the diagnosis of TTP, such as bleeding time, which increases, and the absence or reduction of the ADAMTS 13 enzyme, which is one of the causes of the formation. small thrombi.
The treatment of thrombotic thrombocytopenic purpura should be started as soon as possible, since it is fatal in most cases, since the formed thrombi can block the arteries that reach the brain, reducing blood flow to this area.
Treatment normally indicated by the hematologist is plasmapheresis, which is a blood filtration procedure in which excess antibodies that may be the cause of this disease and excess von Willebrand factor, as well as supportive care, such as haemodialysis, for example. for example, if there is kidney failure. Understand how plasmapheresis is performed.
In addition, your doctor may recommend the use of corticosteroids and immunosuppressive drugs, for example, to combat the cause of PTT and avoid complications.