Acute immune thrombocytopenic purpura: What do we do when things go well?

Immune thrombocytopenic purpura (ITP) is among the more common hematological disorders observed by both paediatric hematologists and general paediatricians. The Children's Hospital of Eastern Ontario, Ottawa, which provides tertiary care to the Ottawa/Hull region with a population of approximately one million, admitted 15 children with a new diagnosis of ITP from December 1, 2000 to November 30, 2001, roughly eight admissions/100,000 children annually (1). This figure is double that of the incidence figure in the study by Lilleyman (2) (four/100,000), in part due to referrals from the surrounding region. In this issue of Paediatrics & Child Health, Berman et al (pages 386–389) address whether some of these admissions could have been dealt with on an out-patient basis. The initial management of a child presenting with acute ITP is fraught with many questions and very few answers. Typical presentation involves a child between the ages of one and 10 years with bruising, petechiae, and/or nosebleeds one to three weeks after a viral infection. Does the child need admission? Does the child need treatment? What treatment should be given – steroids, intravenous immunoglobulin (IVIG) or anti-Rh(D)? Is a bone marrow aspirate (BMA) required for diagnosis before starting treatment, or is it necessary only in atypical cases? The management of acute ITP is grounded more in faith than in science. Individual physicians have a particular way in which they treat their patients (typically based on their training) that they defend with fanatical zeal, considering all other methods to be inferior. Difficulty in answering the above questions lies in the low frequency of adverse outcomes. The majority of patients with ITP do well, no matter what approach is used. Nonetheless, always lurking in the back of one's mind are those rare adverse events, in particular, intracranial hemorrhage (ICH). The problem with rate outcomes is demonstrated in the study by Berman et al because they hoped to show that patients with ‘typical’ ITP were suitable candidates for outpatient therapy, but were thwarted by the absence of any serious bleeds in the 74 patients who they analyzed. Fortunately, there is light on the horizon. The Intercontinental Childhood ITP Study Group, based in Switzerland, is laying the groundwork for an international network that may finally be able to answer many of the questions about the management of this common disorder. In the December 22, 2001 issue of the Lancet, the group presented the results of its ITP registry (3), which involved 1496 children with newly diagnosed ITP from 136 institutions in 38 countries. Seventy-three per cent of the children were admitted to hospital, including 78% of those with an initial platelet count of less than 20·109/L. Patients treated with IVIG were admitted 91% of the time compared with 77% of the time for those treated with corticosteroids, and 47% of the time for those not treated. Fifty per cent of the children had a BMA ranging from 69% in the corticosteroid treatment group to 38% in the IVIG treatment group. Interestingly, the initial management was virtually a three-way tie, with 31% of patients receiving no treatment, 29% receiving IVIG and 33% receiving corticosteroids. Only two cases if ICH were seen during the six months of follow-up (0.13%), with one occurring four months after initial presentation (3). What does this tell us? If a child presents with ITP, depending on whether the physician prefers no treatment, steroids or IVIG, the chance of the patient being admitted to hospital ranges from 47% to 91%, in part because of the practical difficulties of running a 4-to 6-h IVIG infusion as an outpatient. Other than initial treatment, what criteria should be used to admit a child with ITP to hospital? Berman et al were unable to show that children with typical presentations were at any lower risk of ICH, which is not surprising in light of the low rate of ICH in the Intercontinental Childhood ITP Registry (3). In their discussion, the authors suggest that children with a very low platelet count (less than 5·109/L) or significant mucosal bleeding, or families where geographic location and community resources may hinder obtaining urgent care should be admitted. I would add to this list that both the parents and the physician involved need to be comfortable with the child going home, and close follow-up must be arranged. The parents need clear instructions on what signs and symptoms to look for, and who to contact if there are any concerns. These seem like reasonable criteria in view of the low risk of the child having an ICH. As far as initial management is concerned, there is a clear consensus that no therapy is required if the platelet count is greater than 20·109/L and the child does not have significant bleeding. Equally, once the platelet count goes below 20·109/L and there is significant mucous membrane bleeding, treatment is mandatory. However, no consensus exists when the platelet count is low (less than 20·109/L) without bleeding, as demonstrated by the three-way tie in the International ITP Registry. If the decision to treat is made, the main impetus for using IVIG is the concern about administering steroids without a BMA and missing a diagnosis of leukemia. It is difficult for a general paediatrician to arrange a BMA and IVIG tends to be a more convenient approach. In reality, the risk of leukemia is relatively low in the setting of isolated thrombocytopenia (less than 1%), and children with a normal physical examination and normal hemoglobin, white blood cell count and neutrophil count can safely forgo a BMA before starting treatment with steroids (4–6). I would, however, recommend contacting the laboratory to ensure that no lymphoblasts are visible on the blood smear. Children with mild anemia or neutropenia should have either a BMA before starting treatment with steroids or receive IVIG. The management of ITP needs to move beyond dogma and unsubstantiated clinical guidelines to evidence-based practice. What is needed is an ‘ITP Camp David’, where the physicians who admit their patients sit down with the outpatient group, the treaters reconcile with the non-treaters, and the IVIG group carries on a civil conversation with those who use steroid treatment. The formation of the Intercontinental Childhood ITP Study Group is a big step in the right direction that should hopefully bring us closer to that goal. In the meantime, your guess is as good as mine. Fortunately, most children with ITP will do well in spite of their paediatrians' best (or worst) efforts.

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