Discussion of Pediatric Idiopathic Thrombocytopenic Purpura
It is the bleeding disorder that can occur in the pediatric population. ITP is an abbreviation of Idiopathic Thrombocytopenic Purpura. The bleeding occurs as the result of low platelets count, which is responsible for the formation of clots. The deficiency of platelets results in impaired clotting mechanism and thus frequent bleeding.
As the name suggests, the exact etiology is still not known, but many causative factors have been studied in association with ITP. ITP is also called primary immune thrombocytopenic purpura. The bone marrow and the production of platelets are mostly normal. The number of platelets gets reduced as a result of destruction.
The following criteria are set as the definition of ITP:
- Thrombocytopenia (It is defined as the decreased platelet count, <150,000 cubic mm).
- Bone marrow is normal.
- Purpuric rash.
- An absence of any other identifiable causes.
Types of Pediatric Idiopathic Thrombocytopenic Purpura
There are two main types of ITP:
The acute form
It starts after an acute infection and resolves spontaneously within two months. It is the more common form of ITP that occurs in children. It follows viral infections such as rubella, measles, varicella and Epstein-Barr virus.
The chronic form
It persists more than 6 months without having any identified underlying cause. It results from the immune clearance of the platelets. The platelets having the IgG or IgM antibodies are cleared from the circulation by the spleen. The spleen performs both the function of the formation of antibodies and sequestrating the platelets. It is mostly associated with the following factors:
- Female sex.
- The presence of other autoimmune diseases.
- The age of presentation is more than 10 years.
- In the US, there are about 66 cases of ITP out of 1,000,000 per year. In children, the average number of cases per year is 50 out of 1,000,000. About 40% of ITP patients are less than 10 years of age, the condition is most prevalent in children 2 to 4 years old. In adults, the condition is most prevalent in people in the 20 to 50 years range.
- In a study by the International Childhood ITP Registry (ICIS), 2031 children with the condition were studied. The research involved136 centers across 38 countries. According to the study, ITP occurred most frequently in the spring and least frequently in the autumn.
- There relation between chronic ITP in children and Helicobacter pylori has not been proven. One study found H pylori’s occurrence in children with the conditionto be similar tothe general population. Moreover,eliminating H pylori did not have any effect on the recovery of the children.
Pathophysiology of Pediatric Idiopathic Thrombocytopenic Purpura
The peripheral destruction of platelets takes place in ITP. Many patients exhibit antibodies in their blood that attach to the glycoprotein on the platelets’ membrane. The spleen and other reticuloendothelial organs destroy the antibody-coated platelets. In addition to this immunological destruction of the platelets, there is some evidence that the defective platelet production can also be the cause, especially in the chronic type of ITP.
Although the number of megakaryocytes is normal or slightly increased in the bone marrow, the plasma thrombopoietin levels which are responsible for maturation and proliferation of progenitor cells are reduced. This confirms the defective activity of megakaryocytes.
Clinical Features of Pediatric Idiopathic Thrombocytopenic Purpura
The signs and symptoms of ITP include:
- Petechia, ecchymosis, bruising, and purpuric rash.
- Bleeding from mucosal membranes, such as gum bleeding and nose bleeding.
- Bleeding from the urinary tract, conjunctivae, and retina.
- Generalized bruises.
- No lymphadenopathy, hepatosplenomegaly, or other signs of leukemia.
- In the chronic cases, the onset is slow and a patient can be completely asymptomatic.
Diagnosis of Pediatric Idiopathic Thrombocytopenic Purpura
The diagnosis is mostly clinical. The following investigations are performed to confirm the clinical diagnosis:
- Complete blood count: The platelet count is low, usually less than 50,000/cubic mm. In about 10% of the children, there can be mildly reduced red blood cells count.
- The PT (Prothrombin time) and APTT (Activated Partial thromboplastin time) are normal.
- Bleeding time (BT) is prolonged.
- Bone marrow examination may show increased megakaryocytes.
- Platelet-associated IgM and IgG are demonstratable on platelets.
- A CT scan of the head can be performed if there is any suspicion of intracranial hemorrhage.
Management of Pediatric Idiopathic Thrombocytopenic Purpura
The management will be discussed separately for acute and chronic cases of ITP.
Treatment of Acute ITP
- Securing the airway.
- Maintenance of fluids and electrolytes.
- Preventing the trauma.
- Avoid using medicines such as aspirin, chloramphenicol, carbamazepine, sulfonamides, valproic acid, heparin, and digoxin.
- Most of the cases do not require any further treatment.
- Platelets transfusion is started in the emergency cases if the count is significantly dropped.
- IV immunoglobins are the mainstay of therapy. They can raise the count within 2–3 days.
- Corticosteroids (Prednisolone): The dose is 2–4 mg/kg in the divided doses for one to four weeks. It is then slowly tapered off.
- Anti-Rh (D): It is only useful in Rh positive patients. 80% of the children show a response to this treatment.
Treatment of Chronic ITP
- Avoid medicines that suppress the production of platelets.
- Restrict the activities that can increase the risks of trauma.
- Pharmacological therapy includes the IVIG, steroids, anti-Rh D, androgens and immunosuppressive agents (Cyclophosphamide, Rituximab, and Azathioprine).
Most of the chronic cases of ITP keep remitting; therefore, a more useful therapy is needed to maintain the normal platelet count to avoid the repeated bleeding.
It is done in cases which are resistant to the medical therapy. It is considered after one year of persistent thrombocytopenia.
- This procedure is associated with increased risks of infections, especially in very young children; therefore, it is delayed until the child is at least 5 years old.
- The vaccination cover for Hemophilus influenza b, meningococcal, and pneumococcal is provided. Prophylactic penicillin is also given to the patient.
Complications of Pediatric Idiopathic Thrombocytopenic Purpura
Intracranial bleeding is the most feared complication. The other complications are the side-effects of corticosteroids.
- Increased blood sugar levels
- Thinning of skin
Prognosis of Pediatric Idiopathic Thrombocytopenic Purpura
The overall prognosis of Idiopathic Thrombocytopenic Purpura is good. 90% of children will have a spontaneous recovery from the disease.