Silent thyroiditis
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [3]
Synonyms and keywords: Painless thyroiditis; subacute lymphocytic thyroiditis.
Overview
Silent thyroiditis, more specifically and scientifically as subacute lymphocytic thyroiditis, is a member of the group of thyroiditis conditions known as resolving thyroiditis, which includes a very similar condition to silent thyroiditis, postpartum thyroiditis.
Causes
Silent thyroiditis is most likely autoimmune. Hashimoto's thyroiditis is also known as chronic lymphocytic thyroiditis and is, therefore, in the same "family" as silent thyroiditis. It seems that silent thyroiditis may be transient "hashitoxicosis," which is a hyperthyroidism phase before the usual hypothyroidism associated with Hashimoto's thyroiditis.
Ingestion of large or minimal amounts of iodine bring a host of different conditions and usually is not associated with silent thyroiditis.
Diagnosis
History and Symptoms
Silent thyroiditis features a small goiter without tenderness and, like the other types of resolving thyroiditis, tends to have a phase of hyperthyroidism followed by a phase of hypothyroidism then a return to euthyroidism.[1] The time span of each phase is not concrete, but the hypo- phase usually lasts 2-3 months.
The symptoms are those of hyperthyroidism and hypothyroidism during these phases.
Laboratory Findings
Thyroid autoantibodies (anti-thyroglobulin, anti-thyroid peroxidase) may be present, but the extent of their role in silent thyroiditis is unknown.
Other Imaging Findings
During the hyperthyroidism phase, RAIU (Radioactive Iodine Uptake) is suppressed while during the hypothyroidism phase it is increased.[2]