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Intravenous Immunoglobulin Is Effective
Therapy for Acute Idiopathic Thrombocytopenic Purpura
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Question
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In
otherwise healthy children with acute onset idiopathic thrombocytopenic
purpura (ITP), does treatment with IVIG versus no treatment result in more
rapid resolution?
Clinical
Bottom Lines
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- High doses of IVIG
and prednisone can produce a rapid increase in platelet counts in children
with acute ITP and platelet counts under 20,000 (those at high risk for
intracranial hemorrhage).
- The rate of
platelet count response was significantly faster in those given treatment,
and most rapid for those given immunoglobulin.
- Two patients (NNT=2)
would have to be treated with IVIG compared to no treatment in order to
have one whose platelet count rose above 50,000 in less than 3 days.
Three patients (NNT=3) would have to be treated with IVIG compared to
prednisone for the same outcome.
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Summary of Key Evidence
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- A randomized trial
of 53 patients compared intravenous immune globulin G (IVIG), oral
prednisone, and placebo in the treatment of acute ITP.1
- Nineteen patients
received IVIG at 1 gm/kg daily for two days, 18 received prednisone at a
dose of 4 mg/kg (tapered over 21 days), and 16 received no therapy.
Baseline clinical characteristics were similar for all three groups. The
administration of drugs was not blinded.
- Prior to
randomization, subjects were stratified by severity of hemostatic defect.
Inclusion criteria included: age over 6 months and under 18 years;
platelet count less than 20,000; a bone marrow aspirate consistent with
ITP; and no evidence of chronic ITP.
- Primary outcomes
for the study were: number of days with a platelet count under 20,000 and
the number of days required to reach a platelet count over 50,000.
Secondary outcomes were the occurrence of any adverse effect of therapy.
- Median duration of
severe thrombocytopenia after treatment was 1 day for IVIG (p<0.001) and 2
days for prednisone (p<0.01) compared to 4 days for no therapy. Results
between the two treatment groups were not significantly different.
- The median time to
reach a platelet count above 50,000 was 2 days for those in the IVIG group
(statistically different than both prednisone and no therapy)
- Seventy-five
percent of those treated with IVIG had some combination of nausea,
vomiting, headache, and fever. The most common adverse reaction to
prednisone was weight gain.
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Additional
Comments
- The main reason for treating children with acute ITP is the prevention
of intracranial hemorrhage (ICH), a complication that occurs in 1% of
affected children. Randomized studies would require prohibitively large
numbers of patients in order to use this as an outcome of interest.
- Given that acute ITP in childhood is usually self-limited disease, the
inclusion of a no-therapy group in this study is helpful (and rather
unique among other published studies). Both therapies performed better
than no therapy.
- Cost and availability of IVIG are important considerations.
Citation
- Blanchette VS,
Luke B, Andrew M, et al. A prospective, randomized trial of high-dose
intravenous immune globulin G therapy, oral prednisone therapy, and no
therapy in childhood acute immune thrombocytopenic purpura. J Pediatr
1993; 123:989-95.
www.cidpusa.org
www.cidpusa.org/P/ivig.htm
http://www.cidpusa.org/disease.html
http://www.cidpusa.org/Lahore.html
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