Cerebral sinovenous thrombosis and idiopathic nephrotic syndrome in childhood: report of four new cases and review of the literature.

INTRODUCTION: Nephrotic children are prone to develop thromboembolic complications secondary to an acquired hypercoagulable state. Cerebral sinovenous thrombosis (CSVT) is increasingly recognised in this population, but clinical characteristics and outcome are not well documented. PATIENTS AND METHODS: The database of the Canadian Pediatric Ischemic Stroke Registry (Toronto Site) containing prospectively enrolled children from 1992-2004 with CSVT identified four children with NS. A pooled literature analysis retrieved 17 additional cases reports.
RESULTS: CSVT presented in the majority of cases during the first flare or within 6 months after the onset of NS and was found to occur more often in SSNS/SDNS (n=13) than in SRNS (n=4). Clinical manifestations were non-specific and consisted primarily of seizures (n=8) and signs of raised intracranial pressure (n=16). Imaging studies revealed a predilection for superior sagittal sinus involvement (n=21) and rare parenchymal lesions (n=4). The most consistent biological risk factors were a severe hypoalbuminaemia (n=14) and, to a lesser extent, decreased antithrombin (AT) levels (n=9/16). Deficiency of other coagulation inhibitors (protein S, protein C) was not identified. Inherited thrombophilia was documented in a single case, suggesting that acquired, more than genetic, coagulation factors are involved. Anticoagulation was safe, and the outcome was good in most patients, and no recurrence of thrombotic event was reported. DISCUSSION: In conclusion, CSVT is now a well-described complication of NS with potential morbidity. A high index of suspicion is required, especially in young children with NS presenting neurological symptoms. Reliable biological predictors of CSVT are lacking.