Abstract

MARSIGLIA, Italo. La tiroiditis bifásica: un patrón fisiopatológico en las tiroiditis. Gac Méd Caracas. [online]. 2008, vol.116, n.4, pp.315-322. ISSN 0367-4762.

Thyroid dysfunction is commonly observed in the clinical course of thyroiditis. Clinical or subclinical hypothyroidism frequently occurred in chronic autoimmune thyroiditis as a consequence of progressive glandular replacement by fibrosis and atrophy. Also, permanent hypothyroidism is a common sequel of silent thyroiditis, unusual in subacute thyroiditis. Thyroid inflammatory process associated to destruction of glandular epithelium and transitory thyrotoxicosis is known as “destructive thyroiditis”, which frequently occurred in the first months of subacute or silent thyroiditis evolution or, in a little percentage, during the course of chronic autoimmune thyroiditis. Disorders with different pathogenesis, as subacute thyroiditis which is entailed with viral infections or, silent-postpartum or chronic autoimmune thyroiditis,  known autoimmune diseases, are responsible of similarly pathophysiological phenomena which originated “biphasic thyroiditis”. Characteristically, these cases developed sequentially transitory thyrotoxicosis, which is followed by transient hypothyroidism and recovery. In two Venezuelan samples, transitory thyrotoxicosis and hypothyroidism with biphasic patron were observed, respectively, in 86 % and 27 % of thyroiditis subacute cases and, the biphasic patron, in the four cases with silent or postpartum thyroiditis. In the sample of chronic autoimmune thyroiditis, no cases of biphasic thyroiditis were observed. The pathophysiological mechanisms of biphasic thyroiditis are direct consequence of thyroidal inflammation and autoimmunity, which also imply the effects of stimulating or blocking antibodies for the stimulant thyroid hormone receptor. Undoubtedly, this functional patron and its reversibility, constitutes a sui generis behavior in the endocrine glands diseases, in which spontaneous hyper or hypo function usually occurred isolated and permanently. These reasons justify the report of these typical cases of subacute, silent and chronic autoimmune thyroiditis, in which, the patron of biphasic thyroiditis was the most relevant finding of his clinical evolution.

Keywords : Biphasic thyroiditis; Destructive thyroiditis; Transitory thyrotoxicosis; Transitory hypothyroidism; Subacute silent and chronic autoimmune thyroiditis.