See “Risk Factors, Morbidity, and Treatment of Thrombosis in Children and Young Adults With Active Inflammatory Bowel Disease” by Zitomersky et al on page 343.
Thromboembolism (TE) is a severe and potentially life-threatening complication of inflammatory bowel disease (IBD). The increased risk of TE in adults with IBD is well established (1–4), and guidelines for anticoagulation are being instituted as standards of practice (5,6). Until recently, the risk of TE in the pediatric IBD population was not well described, and the present literature on therapeutic measures remains scarce. Although a lower incidence of TE in pediatric patients with IBD compared with adults has been reported (7), a review of TE in pediatric IBD showed that incidence is increasing in this population (8). In a recent retrospective cohort study of hospitalized children in the United States using the Healthcare Cost and Utilization Project Kids’ Inpatient Database, the authors discovered increasing trends of TE in both IBD and non-IBD patients (9). They also concluded that children and adolescents with IBD were at an increased risk for TE, and risk factors for TE included older age, central venous catheter, parenteral nutrition, and an identified hypercoagulable condition.
In this issue of the Journal of Pediatric Gastroenterology and Nutrition, Zitomersky et al (10) report their experience with thromboembolic phenomena in their hospitalized patients with IBD. Incident cases were reviewed retrospectively to identify documented prothrombotic risk factors, prothrombotic medications, recent surgery, and first-degree family history of TE. They examined inflammatory markers and disease activity indices at the time of thrombosis. The length and cost of admission of incident cases of IBD and thrombosis were compared to average costs of admission and length of stay for IBD flares for a 1-year period at their hospital. Type and length of anticoagulation, as well as reason for discontinuation, were also reported for incident cases of IBD with venous TE. Ten patients (1.9%) of 532 children and adolescents admitted with IBD involving the colon were recognized as having had thromboembolic events. Eight patients had panulcerative colitis and 2 had Crohn disease with colonic involvement. Nine patients had a venous TE, 1 had an arterial TE, and 2 of the 10 had recurrent thrombosis. Four patients (3.8%) of 104 with indwelling catheters developed line-associated thrombosis, one of whom was diagnosed as having pulmonary embolism. They reported that severe inflammation and fulminant disease activity were among the hallmarks of thrombosis as determined by inflammatory markers and disease severity indices. Patients with TE experienced substantial morbidity, including cerebrovascular events, pulmonary emboli, and even permanent sequelae such as hemiparesis and cognitive defects. Costs of care also increased in their patients with IBD with thrombotic complications versus those without TE. The risk factors for TE among their hospitalized patients with IBD with colitis included indwelling catheter, first-degree family member with TE, hereditary thrombophilia, smoking, oral contraceptives, and thalidomide. Nine of the 10 patients with TE and IBD colitis were treated with therapeutic low-molecular-weight heparin without requiring transfusion or experiencing a significant decrease in hemoglobin. They documented resolution of the thrombus in 7 patients, persistence in 2 patients, and recurrence in 2 patients.
IBD is a recognized risk factor for thromboembolic events. There is no definite etiology for the increased risk, and there are myriad proposed hypotheses. It is quite evident that children and adolescents with IBD, especially those with severe disease who require hospitalization, are also at an increased risk for thromboembolic events, although the absolute risk may be lower than adults with IBD. The experiences of Zitomersky et al are in line with other studies that have investigated this markedly increasing complication of IBD. Despite having a small cohort of patients with TE, the risk factors they discovered also parallel those from other studies, although tobacco exposure was found to be protective in the IBD group of patients in the article by Nylund et al (9). Anticoagulation may be indicated for certain hospitalized pediatric patients, both with and without IBD, and therefore, caution should be taken when implementing thromboprophylaxis. The increased risk of TE in the presence of severe inflammation should be an integral part of shared decision making regarding therapeutic options, as well as surgical interventions, and may be an important and decisive factor in step-up therapy. Initiating pharmacologic thromboprophylaxis should be based on stratified risk factors that increase the risk for thrombosis such as family history of TE, indwelling catheter, parenteral nutrition, previous TE, hereditary thrombophilia, diminished mobility, and a hypercoagulable state. Larger prospective studies are imperative to determine the type, safety, and efficacy of anticoagulation and thromboprophylaxis to establish guidelines, individualize therapy, minimize morbidity, and improve outcomes in the pediatric IBD population.
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