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Panepinto and Brousseau Pediatric Emergency Care Volume 21, Number 10, October 2005 severity of bleeding can be used to determine the optimal approach for a given child. Some practitioners have begun using clinical grading scales to assess the severity of bleeding. 3,13,14 The grading consists of 4 main categories: asymptomatic, mild, moderate, and severe. The asymptomatic child has no symptoms in the setting of a low platelet count discovered at the time of a blood count obtained for another reason. Mild ITP is defined as petechiae and bruising of the skin, with or without some minor epistaxis. Minor epistaxis is defined as bleeding of short enough duration that there is no significant change in the child’s daily activity. Increased bleeding symptoms and more significant skin and mucosal findings are classified as moderate ITP. Severe ITP is bleeding that requires immediate treatment because of a significant drop in hemoglobin or the life-threatening nature of the bleeding. Approximately 75% of patients have mild symptoms at their initial presentation of ITP, including the majority of children with platelet counts less than 10 10 9 /L. 15 Guidelines using this clinical grading of symptoms were developed in the United Kingdom to provide a reasonable approach to the management of children with acute ITP. 16 Recently, Buchanan and Adix 13 published a clinical grading scale that is similar to that developed in the United Kingdom. Like the United Kingdom scale, there are the categories of asymptomatic, mild, moderate, and severe hemorrhage. This grading scale also has a minor hemorrhage category that recognizes very minimal clinical symptoms of acute ITP defined as 100 petechiae or less with or without 5 or fewer bruises and absence of mucosal bleeding. In addition, the grading can be applied to specific sites of bleeding, which include the skin, epistaxis, oral bleeding, and life-threatening bleeding. This scale, or a variation of this and the United Kingdom grading scale, should prove valuable to determine the best course of therapy related to the severity of bleeding in a child with acute ITP. Consistent grading of severity of bleeding will also be useful in future ITP research. There is a large variability in severity of bleeding symptoms in children presenting with acute ITP from no symptoms to life-threatening hemorrhage. Most commonly, children with ITP present with skin and mild mucosal bleeding symptoms. DIAGNOSIS AND DIFFERENTIAL DIAGNOSIS ITP is a diagnosis of exclusion. Patients have thrombocytopenia (platelet count
Pediatric Emergency Care Volume 21, Number 10, October 2005 Acute Idiopathic Thrombocytopenic Purpura TABLE 1. Treatment for Acute Idiopathic Thrombocytopenic Purpura Treatment Dosing Time to Increase in Platelet Count Observation N/A 3–4 wk N/A Corticosteroid Traditional dose 1–2 mg/kg per d for 7–21 d Complications of Treatment 3–10 d Behavioral changes, glucosuria, hypertension, osteopenia, increase in appetite and weight gain High dose 4 mg/kg per d for 4 d 2–4 d IVIg 0.8–1 g/kg IV for 1–2 d 24 h Fever, nausea, vomiting, chills, headache, aseptic meningitis Anti-D immunoglobulin 50–75 mg/kg IV for 1–2 d 24–48 h Fever, nausea, vomiting, chills, myalgias, hemolysis N/A indicates not applicable. corticosteroids includes decreased clearance of the antibodyplatelet complex and impaired phagocytosis of platelets. 27–31 Early studies of corticosteroids used to treat acute ITP showed that there was some benefit when given in low doses over longer periods compared with placebo. This traditional dosing was 1 to 2 mg/kg of oral prednisone per day for 1 to 3 weeks. 32,33 Time to an increase in platelet count varied from 3 to 10 days. This dose is well tolerated and not usually associated with significant side effects if it is tapered or discontinued within a month. However, this is not commonly used at presentation of acute ITP because of the longer time it takes to see platelet recovery. Higher dose steroids given for a short period have recently been shown to be effective at raising the platelet count within 2 to 4 days. 34–36 The dose of corticosteroids given varied across the studies and ranged between 4 mg/kg per day to 30 mg/kg per day of prednisone or methylprednisolone for up to 4 days. There were no undue side effects noted when a dose of 4 mg/kg per day for 4 days orally was used. 34 The benefits of using corticosteroids are the relative ease of administration in an outpatient or inpatient setting, the low cost compared with other treatments, and the absence of exposure to human plasma. The longer time to platelet increase, however, precludes the use of steroids alone to treat patients who may have moderate or more severe bleeding symptoms at presentation. High-dose corticosteroids are effective initial therapy for acute ITP and are used with some frequency. The Intercontinental Childhood ITP Study Group reported recently that approximately 25% to 40% of children in their registry received corticosteroids as initial therapy when they presented with acute ITP. 1 The relationship of bleeding symptoms or dose of corticosteroids used was not presented in this observational study. Intravenous Ig The third treatment option is intravenous (IV)Ig. IVIg is thought to work, in part, by causing a temporary but prolonged blockade of the Fc receptor of the phagocyte that mediates immune clearance. 31,37,38 This blockade leads to a compensatory increase in the platelet count. Recently, IVIg has been shown in a mouse model to more specifically act by causing up-regulation of the inhibitory receptor FcgRIIb to cause blockade of Fc receptors on splenic macrophages. 39,40 There are a variety of doses of IVIg that may be used, but, most commonly, the dose given is 0 .8 to 1.0 g/kg daily for 1 to 2 days. 41–45 Given at this dose, IVIg leads to a rapid increase in platelet count as early as 24 hours after infusion and has been effective when used for moderate or severe bleeding in acute ITP. The side effects associated with IVIg are fever, chills, headache, nausea, vomiting, and aseptic meningitis. There is also the small risk of an infectious complication as IVIg is an albumin-containing product. Most often, IVIg, which is usually administered over 4 to 6 hours or more, is given in a hospital setting and requires more resources and cost to administer than corticosteroids. However, it is commonly used at first presentation of acute ITP. Anti-D Ig Anti-D Ig, which is purified human IgG directed at the erythrocyte D antigen, has more recently been used to treat acute ITP in children who are nonsplenectomized and who have rhesus-positive (Rh + ) red blood cells. 43,46,47 The mechanism of action of anti-D is similar to IVIg in that it decreases the clearance of platelets. More specifically, anti-D binds to the Rh + red blood cell and sensitizes it to bind to the macrophage Fc receptor and thereby promotes its clearance by the spleen. 31,48 This frees platelet-antibody complexes from being trapped. 48 Higher doses of anti-D (50–75 mg/kg) have been shown to be the most effective at increasing the platelet count within 24 to 48 hours similar to IVIg. 46,47,49,50 Anti-D is given IV over 15 to 30 minutes and thus can be easily administered in an outpatient or emergency department setting. It has also been shown to be less costly than an equivalent dose of IVIg. 51 The side effects of anti-D include headache, fever, chills, nausea, and vomiting and myalgias. 52 In addition, anti- D causes hemolysis and a transient decrease in the hemoglobin n 2005 Lippincott Williams & Wilkins 693 Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
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