• thrombosis
• pulmonary embolism
• diagnosis
• d-dimer

Pulmonary embolism (PE) in childhood is a relatively infrequent occurrence, with an annual incidence of 0.5/10 000 in the general population,1 although the incidence is rising. It is an important diagnosis with significant mortality, in some studies up to 26%, and the potential for morbidity which can include reduced exercise capacity, chronic thromboembolic pulmonary hypertension and bleeding due to anticoagulant therapy.1 There may be a negative impact on quality of life and psychosocial functioning due to an initial life-threatening presentation, physical symptoms of PE, lifestyle modifications required during anticoagulant therapy and uncertainty surrounding risk of recurrence and long-term complications.

According to the results of autopsy studies, PE is an underdiagnosed condition in children. Cohort studies of childhood PE have identified significant diagnostic delay, some reporting a median of 7 days from presentation to diagnosis.2 Whether this relates to the complexity of PE diagnosis in children, who may have confounding comorbid conditions or a failure to consider thromboembolism as part of the differential diagnosis is not clear. Either way, efforts must be made to ensure timely diagnosis of this potentially life-threatening condition.

An understanding of the epidemiology of childhood PE is essential if we are to readily identify those with the condition. There are two peaks in incidence of thrombosis (including PE) during childhood—infancy and adolescence. Affected infants are often those who were born prematurely or who require major surgery early in life, very few presenting in the absence of thrombotic risk factors. A significant proportion of PE in infancy relates to cardiac anomalies and/or cardiac surgery and …