- The single greatest risk factor for thromboembolic disease in children is an indwelling central venous catheter.
- Disease patterns for pulmonary embolism in children and adolescents are similar to those in adults, yet diagnosis and management is often delayed or inappropriate.
- Arterial thromboembolism is more common in neonates and children with cardiac disorders, likely due to the use of umbilical artery catheters, cardiac catheters, ECMO circuits, and valvular disease.
- Advanced imaging studies have historically been the mainstay of diagnosis for pulmonary embolism as well, as most chest radiographs in children are normal.
- Anticoagulation is achieved acutely with unfractionated heparin or low-molecular-weight heparin (LMWH), followed by long-term anticoagulation with either LMWH or warfarin.
Although rare, thromboembolic events (TEs) increasingly occur in children, with a current rate of 5 episodes per 100 000 pediatric hospitalizations.1 Deep vein thrombosis (DVT) is the most common TE in children with pulmonary embolism (PE) relatively rare at 8% of venous thrombotic events (VTE).2 Arterial thromboembolism (ATE) is more common in neonates and children with cardiac disorders, likely due to the use of umbilical artery catheters, cardiac catheters, ECMO circuits, and valvular disease.3 After briefly discussing ATE, this chapter will focus on the risk factors, clinical presentation, diagnosis, and management of venous thromboembolism (VTE), with stroke discussed further in Chapter 59.
ATE leads to higher morbidity and mortality than VTE.4,5 Previously healthy children with no underlying risk factors rarely present with ATE, although 22% of pediatric patients developing ischemic stroke have no identifiable underlying risk factors.6 Among critically ill children, 96% of ATE are catheter related, either secondary to peripheral catheter use or cardiac catheterization.7 Non–catheter-related ATE occur in patients with underlying hematologic risk factors similar to those correlated with VTE, yet also include organ transplantation and vasculitides such as Kawasaki disease and Takayasu arteritis.8,9 Complications of ATE include stroke, limb loss, and dysfunction of the involved distal organs.
Risk factors for developing VTE assume two primary forms: inherited and acquired. Inherited thrombophilias such as protein C10 and S deficiencies,11 antithrombin deficiency,12 and the presence of lupus anticoagulant13 are considered high-risk states, with factor V Leiden disease, prothrombin mutation, elevated factor VIII, hyperhomocysteinemia, elevated lipoprotein (a), dysfibrinogenemia, and hypo/dysplasminogenemia considered lower risk.14,15 Healthy children with a single thrombophilic trait rarely present with TE, but the risk increases with multiple thrombophilic traits or with the addition of acquired risk factors.16,17
Acquired risk factors are numerous. The most consistent risk factor for development of VTE is central venous catheter placement. In neonatal TE, 65% to 90% are catheter related, and 64% of non-neonate TE is associated with central venous lines.3,18 Commonly cited acquired risk factors are listed in Table 52–1. Among medical conditions, one of the most concerning risk factors for TE is cancer. Both acute leukemia and sarcoma ...