ITP is an autoimmune disorder leading to reduced platelet counts.
Commonly referred to as idiopathic, but it is an immune phenomenon.
Epidemiology
Most common bleeding disorder in children aged 1 to 7 years.
Acute ITP: lasts for less than 6 months.
Chronic ITP: persists for more than 6 months.
Majority of cases resolve within 2-4 months, generally presenting in acute form.
Pathophysiology
Triggered by febrile illnesses, often viral infections.
Viral antigens enter the body, leading to antibody formation.
Antibodies cross-react with platelet antigens, particularly the glycoprotein 2b3a complex.
Resulting antibody attachment traps platelets in the spleen, leading to destruction by macrophages and subsequent thrombocytopenia.
Clinical Presentation
History of viral illness followed by symptoms such as:
Petechiae (small bruises)
Mucosal bleeding (e.g., epistaxis)
Prolonged bleeding after trivial trauma
Normal platelet count range: 150,000 to 400,000.
Symptoms worsen when platelet count is:
Less than 20,000: significant bleeding
20,000 to 50,000: petechiae and bruises.
Seasonal clustering of cases observed.
Differential Diagnosis
Differentiate ITP from:
Bone marrow failure
Malignancies
Hypersplenism
Laboratory Investigations
CBC shows:
Reduced platelet count
Normal other hematological parameters
Peripheral smear:
Normal, no malignant cells observed.
Bone marrow examination:
Increased megakaryocytes, indicating production is not hampered (unlike marrow failure).
Clinical Considerations
Children with ITP typically do not appear toxic or sick.
If a sick child presents, consider other serious conditions such as malignancy, sepsis, malaria, dengue, or disseminated intravascular coagulation (DIC).
Treatment
If platelet count > 20,000 and no bleeding occurs:
Observation is recommended.
If bleeding is present:
Administer IVIG (1g/kg/day for 1-2 days).
For Rh-positive children, consider anti-D immunoglobulin (50-75 mg/kg).
Steroids (initially dexamethasone followed by prednisolone).
In cases of serious hemorrhage:
Platelet transfusion combined with steroids.
Management of Chronic ITP
For chronic ITP (lasting > 6 months):
Treatments include:
Splenectomy (removal of the spleen)
Corticosteroids
Other medications: Danazol, Vincristine, Cyclosporine, Azathioprine, Rituximab.