Silent thyroiditis in an eleven-year-old girl, associated with transient increase in serum IgM and thyroid hormone

An 11-year-old-girl with silent thyroiditis associated with a transient increase in serum IgM and thyroid hormone is described. The levels of serum IgM decreased from 4.38 g/L to 3.35 g/L after 1.5 months at the same time as thyroid hormones returned to normal. An unidentified antecedent infection or exposure to antigen causing the increase in serum IgM might have triggered the occurrence of silent thyroiditis in this patient, although a search for viral antibodies revealed no significant titer changes during the course of the disease.