Symptoms of thrombotic thrombocytopenic purpura

Idiopathic (autoimmune) thrombocytopenic purpura can be acute, chronic and recurrent. In the acute form, the platelet count normalizes (more than 150,000/mm3 ⁾ within 6 months after diagnosis without relapses. In the chronic form, thrombocytopenia less than 150,000/mm3 ^lasts more than 6 months. In the recurrent form, the platelet count decreases again after returning to normal. The acute form is more typical for children, while the chronic form is more typical for adults.

Because idiopathic thrombocytopenic purpura is often transient, the true incidence is unknown. The reported incidence is about 1 in 10,000 cases per year (3-4 in 10,000 cases per year in children under 15 years of age).

Symptoms of acute and chronic idiopathic thrombocytopenic purpura

Clinical signs	Acute ITP	Chronic ITP
Age	Children 2-6 years old	Adults
Floor	Doesn't play a role	M/F-1:3
Seasonality	Spring time	Doesn't play a role
Previous infections	About 80%	Usually no
Associated autoimmune conditions (SLE, etc.)	Not typical	Typical
Start	Spicy	Gradual
Platelet count, mm3	More than 20,000	40,000-80,000
Eosinophilia and lymphocytosis	Typical	Rarely
IgA level	Normal	Reduced
Antiplatelet antibodies	-	-
GpV	Often	No
Gpllb/llla	Rarely.	Often
Duration	Usually 2-6 weeks	Months and years
Forecast	Spontaneous remission in 80% of cases	Unstable long-term course

As stated above, the pathogenesis of idiopathic thrombocytopenic purpura is based on increased destruction of autoantibody-laden platelets by cells of the reticulohistiocytic system. Experiments with labeled platelets have shown that the lifespan of platelets decreases from 1-4 hours to several minutes. The increase in the content of immunoglobulins (IgG) on the platelet surface and the frequency of platelet destruction in idiopathic thrombocytopenic purpura are proportional to the level of platelet-associated IgG (PAIgG). The targets for autoantibodies are glycoproteins (Gp) of the platelet membrane: Gp Ilb/IIIa, Gp Ib/IX and Gp V.

People with the HLA phenotype B8 and B12 have an increased risk of developing the disease if they have precipitating factors (antigen-antibody complexes).

The peak incidence of idiopathic thrombocytopenic purpura occurs between the ages of 2 and 8 years, with boys and girls getting sick with equal frequency. In children under 2 years of age (infantile form), the disease is characterized by an acute onset, a severe clinical course with the development of deep thrombocytopenia less than 20,000/mm ³, a poor response to exposure, and frequent chronicization of the process - up to 30% of cases. The risk of the debut of chronic idiopathic thrombocytopenic purpura in children is also increased in girls over 10 years of age with a disease duration of more than 2-4 weeks before diagnosis and a platelet count of more than 50,000/mm ³.

In 50-80% of cases, the disease occurs 2-3 weeks after an infectious disease or immunization (smallpox, live measles vaccine, etc.). Most often, the onset of idiopathic thrombocytopenic purpura is associated with non-specific upper respiratory tract infections, in approximately 20% of cases - specific (rubella, measles, chickenpox, whooping cough, mumps, infectious mononucleosis, bacterial infections).

Differences between chronic infantile and chronic childhood idiopathic thrombocytolenic purpura

Signs	Chronic infantile IHL	Chronic childhood ITP
Age (months)	4-24	More than 24
Boys/Girls	3:1	3:1
Start	Sudden	Gradual
Previous infections (viral)	Usually no	Often
Platelet count at diagnosis, in mm3	More than 20,000	40,000-80,000
Response to treatment	Bad	Temporary
Frequency of total incidence, %	30	10-15

The symptoms of idiopathic thrombocytopenic purpura depend on the severity of thrombocytopenia. Hemorrhagic syndrome manifests itself in the form of multiple petechial-bruise rashes on the skin, hemorrhages on the mucous membranes. Since petechiae (1-2 mm), purpura (2-5 mm) and ecchymosis (more than 5 mm) can also accompany other hemorrhagic conditions, differential diagnosis is made based on the number of platelets in the peripheral blood and the duration of bleeding.

Bleeding occurs when the platelet count drops below 50,000/mm3 ^. The risk of serious bleeding occurs with deep thrombocytopenia below 30,000/mm3 ^. At the onset of the disease, nasal, gingival, gastrointestinal and renal bleeding are usually uncharacteristic; coffee ground vomiting and melena are rare. Severe uterine bleeding is possible. In 50% of cases, the disease manifests itself in a tendency to form ecchymoses at the sites of bruises, on the anterior surface of the lower extremities, over bony prominences. Deep muscle hematomas and hemarthroses are also uncharacteristic, but can be a consequence of intramuscular injections and extensive injuries. With deep thrombocytopenia, hemorrhages occur in the retina, and rarely - bleeding into the middle ear, leading to hearing loss. Cerebral hemorrhage occurs in 1% of cases of acute idiopathic thrombocytopenic purpura, and in 3-5% of cases of chronic idiopathic thrombocytopenic purpura. It is usually preceded by headache, dizziness, and acute bleeding in some other location.

During an objective examination, splenomegaly can be detected in 10-12% of children, especially at an early age. In this case, differential diagnosis is carried out with leukemia, infectious mononucleosis, systemic lupus erythematosus, hypersplenism syndrome. Enlargement of the lymph nodes in idiopathic thrombocytopenic purpura should not be present, unless it is associated with a previous viral infection.

Secondary thrombocytopenic purpura

As stated earlier, thrombocytopenia may be idiopathic or secondary to a number of known causes. Secondary thrombocytopenia, in turn, can be divided depending on the number of megakaryocytes.

Thrombopoietin deficiency

A rare congenital cause of chronic thrombocytopenia with the appearance of numerous immature megakaryocytes in the bone marrow is thrombopoietin deficiency.

Treatment consists of transfusions of plasma from healthy donors or patients with idiopathic thrombocytopenic purpura, which leads to an increase in the platelet count and the appearance of signs of megakaryocyte maturation, or replacement therapy with thrombopoietin.