title: 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 L-thyroxine treatment.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  We would like to attract the attention of paediatricians to the possibility of bleeding due to decreased activity of vWF in hypothyroid children.
authors.affiliation: Dr. Behçet Uz Children's Hospital, Izmir, Turkey. drolukman2002@yahoo.com
authors.forename: Ozgür
authors.initials: O
authors.lastname: Olukman
authors.forename: Ulkü
authors.initials: U
authors.lastname: Sahin
authors.forename: Tülay
authors.initials: T
authors.lastname: Kavakli
authors.forename: Kaan
authors.initials: K
authors.lastname: Kavakli
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000097:blood* / Q000150:complications / Q000188:drug therapy; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D013974:Thyroxine / Q000627:therapeutic use*; D014842:von Willebrand Diseases / Q000209:etiology*
chemical_list: D013974:Thyroxine