Isolated thrombocytopenia in childhood: what if it is not immune thrombocytopenia?

Abstract

Introduction: Childhood immune thrombocytopenia (ITP) remains a diagnosis of exclusion when isolated thrombocytopenia is not part of another disease process. In practice, the diagnosis of ITP can only be confirmed when thrombocytopenia resolves or is excluded after the recognition of a primary cause.

Methods: The records of 87 consecutive children with isolated thrombocytopenia seen over a nine-year period in a private paediatric haematology practice were reviewed retrospectively. Children in whom a primary cause was eventually found were the subjects of a further descriptive study.

Results: 9 (10%) children with isolated thrombocytopenia were not diagnosed with ITP because a primary disease was found. Of these nine cases, four had thrombocytopenia recognised during the neonatal period, consisting of perinatal cytomegalovirus infection (n = 2), meconium aspiration pneumonia (n = 1) and transient abnormal myelopoiesis associated with Down syndrome (n = 1). The remaining five children were each found to have familial thrombocytopenia, portal hypertension, cutaneous mastocytosis, May-Hegglin anomaly and systemic lupus erythematosus. Two of them had a history of failure of response to corticosteroid therapy.

Conclusion: Secondary thrombocytopenia is not uncommon in a tertiary paediatric specialty practice with adequate evaluation. Thrombocytopenia occurring during the newborn period and failure of steroid therapy are predictive of secondary cases.

Keywords: differential diagnosis; idiopathic thrombocytopenic purpura; immune thrombocytopenia; neonatal thrombocytopenia; secondary thrombocytopenia.

Fig. 1

Photomicrograph of the peripheral blood film (Giemsa stain × 100) of a patient with perinatal cytomegalovirus infection shows an atypical lymphocyte (AL) and a normal, small lymphocyte (SL).

Fig. 2

Photomicrograph of the peripheral blood film (Giemsa stain × 100) of a patient with neonatal transient abnormal myelopoiesis shows two large-sized blasts. The blast on the left side has a blebby cytoplasmic border suggestive of a megakaryoblastic origin.

Fig. 3

Photomicrograph of the peripheral blood film (Giemsa stain × 100) of a patient with May-Hegglin anomaly shows two neutrophils with cytoplasmic basophilic inclusions (Döhle bodies, arrows) alongside a giant platelet (GP) that is approximately the size of a red cell.