Acquired von Willebrand's syndrome associated with decrease of plasminogen activator and its inhibitor during hypothyroidism.
OBJECTIVE
In a prospective study we searched for von Willebrand's syndrome during hypothyroidism and investigated the effects of treatment with thyroid hormones on plasma concentrations or activities of the factors involved in von Willebrand's disease in addition to tissue plasminogen activator and plasminogen activator inhibitor 1.


METHODS
Eleven patients with hypothyroidism were tested. Factor VIII coagulant activity (VIIIc), von Willebrand factor (vWf:Ag), von Willebrand factor activity (vWf:RCo), tissue plasminogen activator antigen (tPA) and plasminogen activator inhibitor activity (PAI) was monitored before and after correction of hypothyroidism by hormone supplementation.


RESULTS
Five patients had laboratory evidence of type I von Willebrand's disease. The other six patients had concentrations or activities of the factors involved in von Willebrand's disease within the normal range. In all cases except one, during thyroxin treatment, von Willebrand factors returned to normal if initially low, or increased clearly if initially normal. With the correction of hypothyroidism, an increase of tPA was noted in the eleven patients, associated with a significant increase of PAI.


CONCLUSIONS
Laboratory evidence of von Willebrand's disease is common during hypothyroidism. Study of plasminogen activator and its inhibitor suggest a decrease of von Willebrand factor synthesis during hypothyroidism.
Levesque
H
H
Service de Médecine Interne, Centre Hospitalier Universitaire de Rouen-Boisguillaume, France.
Borg
J Y
JY
Cailleux
N
N
Vasse
M
M
Daliphard
S
S
Gancel
A
A
Monconduit
M
M
Courtois
H
H
D000328:Adult; D000368:Aged; D005169:Factor VIII / Q000032:analysis; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000150:complications* / Q000628:therapy; D008297:Male; D017395:Plasminogen Activator Inhibitor 1 / Q000097:blood*; D010960:Plasminogen Activators / Q000097:blood*; D011446:Prospective Studies; D014842:von Willebrand Diseases / Q000097:blood / Q000209:etiology*; D014841:von Willebrand Factor / Q000032:analysis
D017395:Plasminogen Activator Inhibitor 1; D014841:von Willebrand Factor; D005169:Factor VIII; D010960:Plasminogen Activators