Immune thrombocytopenic purpura (ITP) is a condition marked by a decrease in the number of platelets in the blood, known as thrombocytopenia. This leads to hemorrhages in the skin and other organs.
It is important to discern the disease from the symptom known as purpura. Purpura is a symptom characterized by the presence of purple or brown skin spots, which can manifest in various bleeding disorders, including ITP.
It is better to call it immune thrombocytopenic purpura instead of idiopathic thrombocytopenic purpura, in order to avoid the term idiopathic and give importance to the immune mechanism of the disease.
ITP is a very rare disease, and the diagnosis is not easy.
Immune thrombocytopenic purpura is caused by the immune system. It produces antibodies (particularly immunoglobulin G or IgG) against platelets. These antibodies lead the spleen to identify platelets as foreign cells and destroy them.
In addition to the increase of platelet destruction, there is a decrease in platelet production in the bone marrow, although the exact cause remains unclear.
As a result, the count of platelets in the bloodstream decreases. The disease is not considered a genetic condition but may be triggered by another disease sometimes with predisposing genetic factors.
Some of the diseases that trigger the ITP are viral infections (particularly HIV and Hepatitis B and C), lymphoid tumors (particularly chronic lymphoid leukemia), autoimmune diseases (particularly systemic lupus erythematosus) and in certain geographic areas, infection with Helicobacter pylori.
In children, it often appears after a virus infection. Acute ITP is most prevalent among children aged two to nine.
Platelets are essential in blood clotting and wound healing. They also play a crucial role in fighting against infections.
As a result, people with any type of thrombocytopenia are at a higher risk of bleeding and infections.
Patients with ITP may remain asymptomatic, and the condition is only detected through a blood test indicating a low platelet count.
In some cases, frequent bleedings may be present, that is common in all types of thrombocytopenia:
Paradoxically, in some cases, symptoms of thrombosis (excessive clot formation) may arise at the onset of the disease without a clear explanation.
In patients with a diagnosis of ITP who have already been treated, the risk of thrombosis increases with the use of medications such as corticosteroids and significantly increases if a splenectomy (spleen removal) is necessary.
Additionally, a tendency towards infections and persistent fatigue, or asthenia, are other common symptoms observed in individuals with ITP.
The diagnosis of ITP is established through a combination of clinical history, physical examination and platelet count.
Nontrauma-related bleeding is usually not a problem as long as the platelet count remains above 20.000/mm3. Traumatic hemorrhage can appear when platelet counts range between 40.000 and 60.000/mm3. Coagulation tests are normal except a prolonged bleeding time.
The main aim of the diagnosis is to exclude all other potential causes of thrombocytopenia, making ITP a diagnosis of exclusion. Recommended tests when ITP is suspected include:
Other tests, such as immunologic tests, will be performed by a hematologist depending on the case.
Treatment is not required in patients with mild thrombocytopenia, and is reserved for cases with frequent bleeding due to thrombocytopenia or patients with platelet count below 20.000/mm3.
The goal of the therapy is to halt the bleeding and elevate the platelet count above 20.000/mm3.
In cases of high risk of bleeding, initial hospitalization might be necessary.
The treatment options for ITP include:
If corticosteroids do not work, the recommended treatment is:
In cases where patients do not respond to these treatments, combinations of medications may be explored, or reconsideration of the ITP diagnosis might be necessary. Unfortunately, ITP cannot be prevented.