Pediatr Blood Cancer Anticoagulant Therapy in Head Injury-Associated Cerebral Sinovenous Thrombosis in Children Frederico Xavier, MD, 1 Patcharee Komvilaisak, MD, 1 Suzan Williams, MD, FRCPC, 1 Abhaya V. Kulkarni, MD, FRCSC, 2 Gabrielle deVeber, MD, MHSc, FRCPC, 3 and Mahendranath D. Moharir, MD, MSc, FRACP 3 * INTRODUCTION Pediatric non-neonatal cerebral sinovenous thrombosis (CSVT) has an annual incidence of 0.34–0.67/100,000 children/year [1–5]. CSVT presents with non-specific neurological symptoms including seizures, altered consciousness, and raised intracranial pressure [2,4]. Risk factors for CSVT include the classic Virchow triad of blood stasis, vessel wall changes, and hypercoagulability [4–6]. Over 90% of the children with CSVT have at least one identifiable risk factor [7]. Head injury is one risk factor associated with CSVT [8–10]. Head injury-associated CSVT (HIA-CSVT) involves prothrombotic elements of (i) mechanical shearing injury to the dural venous sinuses causing tearing of venous endothelium; and (ii) extrinsic compression of dural venous sinuses causing venous stasis [11,12]. Although the safety of anticoagulation therapy (ACT) is now established in childhood CSVT in general [7,13–16], presence of significant intracranial hemorrhage (ICH) at diagnosis poses a dilemma in the decision to initiate ACT in HIA-CSVT. Hence, HIA- CSVT presents a greater challenge, as in this condition ICH occurs not only due to the natural pathophysiology of CSVT but also, to a greater extent, due to the direct mechanical injury to the brain [17]. This manifests as diffuse axonal injury, dural tears, subdural, subarachnoid, epidural, intraventricular hemorrhage, and parenchy- mal hemorrhagic contusions [18]. Adult data supports the safety and efficacy of ACT even in the presence of ICH [19–21]. There are few studies that have addressed ACT in HIA-CSVT [4,5,10,22–27]. Published consensus-based guidelines for pediatric stroke treatment [28,29] and adult CSVT management [1,5] have not specifically addressed ACT for HIA-CSVT. As a result, management decisions are based on the treating physician/surgeon’s preference. In this study, we describe our experience of a series of children with HIA- CSVT who received ACT. PATIENTS AND METHODS Following institutional Research Ethics Board approval, consecutive cases of radiologically confirmed computed tomogra- phy/magnetic resonance (CT/MR venography) HIA-CSVT were retrospectively identified from the Pediatric Stroke Registry in our Children’s Stroke Program at the Hospital for Sick Children, Toronto, Canada, from 1998 to 2012. Subjects were consented and enrolled prospectively in the registry following confirmation of stroke, including CSVT, diagnosis. Neonates (<28 days) were excluded from this study. Clinical and radiological features at presentation, ACT, radiological (recanalization), and clinical outcome (Pediatric Stroke Outcome Measure, PSOM [30]) were collected from the registry, supplemented by chart review. Data were analyzed descriptively. Based on our institutional CSVT treatment guidelines, ACT is initiated at diagnosis in all children with CSVT without significant ICH or other contraindications. Total treatment duration is up to 6 months. Non-contrast head CT is performed on day 3 of treatment (earlier if clinically indicated by new or worsening of pre-existing seizures and/or neurological deficits and/or deterioration in level of consciousness) to screen for hemorrhagic complications in the form of increased/new ICH and, if present, ACT is withheld until it is clinically deemed to be safe for resumption and ICH is radiologically stable or improving. If ACT is not initiated at diagnosis, CTV/MRV is recommended 5–7 days post-diagnosis or earlier if clinically indicated (new onset/worsening of seizures/ neurological deficits/deterioration in level of consciousness, etc.) to Background. Head injury is a risk factor for cerebral sinovenous thrombosis (CSVT) in children. Literature concerning head injury- associated CSVT (HIA-CSVT) is scarce. Data supporting safety and efficacy of anticoagulant therapy (ACT) in childhood CSVT is emerging. However, intracranial hemorrhage (ICH) occurs frequent- ly in children with HIA-CSVT at diagnosis making initiation of ACT controversial due to the fear of worsening of ICH. Procedure. We conducted a retrospective descriptive review of a consecutive cohort of children with HIA-CSVT from 1998 to 2012. Results. Twenty patients (14 males, mean age 7 years) with HIA-CSVT were identified. Most (19/20 [95%]) had significant ICH at diagnosis. None received ACT at diagnosis. Fourteen (70%) were later (median 7 days post- trauma, range 2–48 days) treated with ACT due to CSVT persistence (nine) and propagation (five), despite ICH in 13. None of the treated patients, including the 13 with pre-existing ICH, had significant worsening of hemorrhage. Three (21%) treated patients had minor asymptomatic extension of their hemorrhage and further ACT was withheld. No patient died while on ACT. No patient experienced CSVT propagation on ACT. Clinical outcomes were normal (no neurologic deficits) in 5/20(25%), mild neurological deficits in 10/20 (50%), and moderate-severe neurological deficits in 5/20(25%). Small sample size did not permit assessment of the effect of ACT on outcome. Conclusions. Anticoagulant therapy is safe in selected children with HIA-CSVT. ICH is not an absolute contraindication to ACT in children with HIA-CSVT. Pediatr Blood Cancer # 2014 Wiley Periodicals, Inc. Key words: CSVT; head-injury; pediatric 1 Thrombosis Service, Division of Hematology/Oncology, Department of Pediatrics, The Hospital for Sick Children and University of Toronto, Ontario, Canada; 2 Division of Neurosurgery, The Hospital for Sick Children and University of Toronto, Ontario, Canada; 3 Pediatric Stroke Program, Division of Neurology, Department of Pediatrics, The Hospital for Sick Children and University of Toronto, Ontario, Canada Grant sponsor: Pfizer Conflict of interest: Nothing to declare.  Correspondence to: Mahendranath Moharir, The Hospital for Sick Children, 555 University Ave, Toronto, Ontario, Canada M5G1X8. E-mail: mahendranath.moharir@sickkids.ca Received 3 March 2014; Accepted 10 June 2014  C 2014 Wiley Periodicals, Inc. DOI 10.1002/pbc.25168 Published online in Wiley Online Library (wileyonlinelibrary.com).