Iodine‐induced thyrotoxicosis: analysis of eighty‐five consecutive cases

Abstract

Iodine-induced thyrotoxicosis was documented in eighty-five cases. Eighty per cent occur in apparently normal thyroid glands; 60% among them occur in males. Amiodarone accounted for 50% of iodine-induced thyrotoxicosis. Mean thyroid hormone levels at diagnosis were: FT1: 21.7 (normal mean: 7.5, arbitrary units); T3: 4.53 nmol 1(-1) (normal: 2.30 nmol 1(-1). Mean 131I- 24-h uptake was 3.5% (normal range in France 25-45%) and was activated by exogenous TSH (mean 27%). The spontaneous cure in nontreated cases was observed within an average 6 months. A phase of biological hypothyroidism (mean FT1: 3.7, T3: 1.23 nmol 1(-1), TSH: 9.6 microU ml-1 (normal TSH range: 1-7 microU ml-1] preceded the return to euthyroidism. Intrathyroid iodine content measured by X-ray fluorescence was high, then fell gradually. Thyroid tissue study showed a large quantity of intrathyroid iodine and the overiodination of thyroglobulin. Histological and electron microscopic studies are reported. Prednisone and in some cases propylthiouracile were found to be effective.

Amiodaron i tarczyca

“…Z tego powodu po odstawieniu AMIO może się pojawić zaostrzenie objawów sercowych oraz nasilenie objawów nadczynności tarczycy [38,51]. Istotne jest również, że DEA wiąże się z wewnątrz--komórkowym receptorem dla T3 i działa jako antagonista T3, stąd kontynuowanie stosowania AMIO i leczenie lekami przeciwtarczycowymi (ATDs) może być jedyną opcją u niektórych chorych [19].…”

“…The decision regarding the continuation or otherwise of AMIO is difficult, with no definitive answer. Consideration must be given to the benefit of AMIO on life-threatening arrhythmias, the fact it has such a long half-life (and hence no immediate benefit on thyroid status if withdrawn), and the fact that AMIO reduces T4 to T3 conversion, so an initial exacerbation of thyrotoxic symptoms may occur on its cessation [38,51].…”

Management of amiodarone-related thyroid problems

“…reduces T4 to T3 conversion so an initial exacerbation of thyroid symptoms may occur on its cessation [Leger et al 1994;Mulligan et al 1993]. If amiodarone can be substituted with other modes of therapy, such as other antiarrhythmic drugs or an implantable defibrillator, then stopping amiodarone may be a viable option.…”

Thyroid Dysfunction in Women With Menopausal Symptoms

“…Iodine-induced hyperthyroidism (jodbasedow phenomenon) is seen in patients with nontoxic multinodualr goiter after the excessive intake of iodine or iodine-containing substances (25,26) High-sensitivity TSH assays have simplified the use of drugs and careful dose adjustments (6,8 …”