Povidone-iodine-induced transient triiodothyronine thyrotoxicosis in a Japanese patient with prolonged habitual gargling: A case report and literature review.

Rationale: Iodine-induced hyperthyroidism and triiodothyronine (T3) thyrotoxicosis in patients who routinely gargle with povidone-iodine (PVP-I) gargling solution are rare in Japan.

Patient Concerns: A 50-year-old man presented to our hospital for a close examination of an enlarged thyroid, which was noted during a complete health checkup. The thyroid was slightly enlarged with no palpable nodules.