Acquired von Willebrand's syndrome causing a hemorrhagic diathesis in a patient with hypothyroidism.

The occurrence of bleeding diathesis with menorrhagia and easy bruising may occur in patients with moderate to severe hypothyroidism sometimes linked to acquired von Willebrand's disease (VWD). We describe a patient with profound hypothyroidism in whom the diagnosis of hypothyroidism was established while evaluating uncontrolled gingival bleeding after a dental procedure. Thyroid hormone replacement led to a rise in von Willebrand factor, factor VIIIC, and a significant fall in the elevated bleeding time from 15 to 8 min. Acquired von Willebrand's disease is an unusual manifestation of hypothyroidism and is reversible.