Chapter 41 Idiopathic Thrombocytopenic Purpura
PATHOPHYSIOLOGY
Idiopathic thrombocytopenic purpura (ITP) is one of the most common acquired, noninherited bleeding disorders. ITP is a condition in which the number of circulating platelets is reduced in the presence of normal marrow. The thrombocytopenia results from an antibody-mediated or transient immune platelet destruction process. Generally, ITP is preceded by a vaguely defined febrile illness 1 to 6 weeks before onset of symptoms. On occasion, it may occur as a result of bone marrow suppression following chemotherapy. Clinical manifestations vary considerably. ITP can be classified into three types: acute, chronic, and recurrent (Box 41-1). Children are initially seen with the following symptoms: (1) fever, (2) bleeding, (3) petechiae, (4) purpura with thrombocytopenia, and (5) anemia. Prognosis is favorable, especially in children with the acute form.
INCIDENCE
1. The age range of peak incidence is 2 to 5 years.
2. Frequency is 4 to 8 cases in 100,000 children per year.
3. ITP affects males and females equally.
4. ITP occurs more commonly in white individuals.
5. Eighty percent of ITP in children is the acute type.
6. Incidence is seasonal—occurrence is more frequent in winter and spring.
7. Of affected children, 50% to 85% have a viral illness before onset of ITP.
8. Of affected children, 10% to 25% develop the chronic form of ITP.
LABORATORY AND DIAGNOSTIC TESTS
1. Platelet count—decreased to less than 40,000/mm3 and often less than 20,000/mm3
2. Complete blood count—anemia results from inability of red blood cells to use iron
3. Bone marrow aspiration—increased megakaryocytes
4. White blood cell count—mild to moderate leukocytosis; mild eosinophilia
5. Platelet antibody tests—done when diagnosis is questionable
6. Tissue biopsy of skin and gingiva—diagnostic
7. Antinuclear antibody test—to rule out systemic lupus erythematosus
8. Slit-lamp examinations—to screen for uveitis
9. Renal biopsy—to diagnose renal involvement
10. Chest radiographic study and pulmonary function test—diagnostic for pulmonary manifestations (effusion, interstitial pulmonary fibrosis)
MEDICAL MANAGEMENT
The goal of treatment in ITP is the reduction of antibody production and platelet destruction, and elevation and maintenance of the platelet count. Corticosteroids are often used as the initial therapy for ITP. If the child does not respond to the corticosteroid regimens, intravenous immune globulin (IVIG) is administered. IVIG stimulates a rapid rise in platelet count within 24 hours of administration. Immunosuppressants (vincristine and cyclophosphamide) may be used in difficult cases. A splenectomy may be performed if ITP lasts longer than 1 year or the child is older than 5 years of age.
NURSING INTERVENTIONS
1. Monitor child’s clinical status.
2. Monitor for and prevent infection.
3. Monitor child’s response to blood product transfusions (whole blood, packed cells, platelets).
4. Monitor child’s therapeutic and untoward response to administration of medications.
5. Promote rest and conservation of child’s energy.
6. Provide diversional and age-appropriate activities for child during periods of limited activities (see Appendix F).
7. Provide age-appropriate explanations before procedures, treatments, and surgery, if splenectomy is indicated (see the Preparation for Procedures or Surgery section in Appendix F).
Discharge Planning and Home Care
1. Provide parents and child with instructions about administration of medications.
2. Instruct parents and child to monitor for signs and symptoms of thrombocytopenia and report immediately (i.e., petechiae, ecchymosis, blood in urine or stool, and headache).
3. Instruct parents to monitor child’s activities.
4. Instruct parents to avoid contact by child with persons who have infections, especially upper respiratory tract infections.
5. Instruct parents to avoid use of over-the-counter medications that may affect clotting (i.e., antihistamines, aspirin, other nonsteroidal antiinflammatory drugs).
