Investigation of Acquired Von Willebrand Syndrome in Children with Hypothyroidism: Reversal after Treatment with Thyroxine

Abstract

Background: Acquired von Willebrand Syndrome (AvWS) is a rare bleeding disorder associated with various underlying conditions. Many case reports have been published so far on bleeding tendency in hypothyroidism resembling AvWS. Objective: This study was designed to define the relationship between hypothyroidism and AvWS and to investigate the effects of Lthyroxine treatment. Subjects: Twenty four hypothyroid patients were included in the study. Nineteen patients were evaluated during treatment, 5 patients were evaluated before hormone replacement. Methods: Complete coagulation screening tests including levels of von Willebrand Factor antigen (vWF:Ag) and functional activity (vWF:RCo) were measured by thrombocyte aggregometer.Results: We demonstrated low vWF:Ag and vWF:RCo in 13 patients. Two of the 13 patients were diagnosed as AvWS, while another 2 patients were diagnosed as hereditary vWD Type 1. The remaining patients are still being followed-up. Conclusion: We would like to attract the attention of paediatricians to the possibility of bleeding due to decreased activity of vWF in hypothyroid children.

Acquired von Willebrand Syndrome in Children

“…22 The AVWS associated with hypothyroidism differs from the other forms of AVWS: there is a reduction regarding the synthesis and release of VWF that is not associated with a reduced half-life because of either autoantibodies or secondary structural changes regarding the VWF multimers. 23…”

“…22 The AVWS associated with hypothyroidism differs from the other forms of AVWS: there is a reduction regarding the synthesis and release of VWF that is not associated with a reduced half-life because of either autoantibodies or secondary structural changes regarding the VWF multimers. 23 AVWS has been described in some pediatric patients with Wilms' tumor and with embryonal adenomas of the kidney. 24,25 There is no evidence of autoantibodies against VWF or adsorption of VWF onto tumor cells.…”

Treatment of acquired von Willebrand syndrome in childhood

“…22,23 Low levels of VWF may be a common finding in pediatric patients with hypothyroidism but often with minimal or no symptoms. 24 AVWS seen in children with hypothyroidism resolves with replacement of thyroxine. However, prophylactic DDAVP should be considered prior to thyroid biopsy or other surgery in these patients prior to correction of the thyroid hormone deficiency.…”

Thyroid dysfunction and hematopoietic system

“…В исследовании детской популяции из 24 паци ентов с гипотиреозом низкий фактор Виллебранда был выявлен в 13 случаях, из них у 2 пациентов была диагностирована приобретенная болезнь Вилле бранда, еще у 2 -наследственная болезнь Виллеб ранда [17]. В описанных в литературе случаях низкий фактор Виллебранда, по видимому, связан с сокра щением его синтеза и/или секреции.…”