Abstract

MARSIGLIA G, Italo. Enfermedad tiroidea autoinmune: Estudio clínicoepidemiológico*. Gac Méd Caracas. [online]. 2008, vol.116, n.1, pp.23-36. ISSN 0367-4762.

This prospective clinical-epidemiologic study aboutautoimmune thyroid disease, in a Venezuelan sample of 1 000 patients, established in 9.9 % the prevalence of thyroid diseases; autoimmune thyroid disease was the most common thyroid disease with a relative frequency of 42 % of all thyroid diseases cases and with prevalence of 4.2 %. Forty two cases of autoimmune thyroid disease were observed: 27 with chronic autoimmune thyroiditis, 4 with silent and postpartum thyroiditis, one with amiodarone-induce thyrotoxicosis and 11 with Graves’ disease. One female initially with Graves’ disease was observed after 40 years with chronic autoimmune thyroiditis, an alternative in autoimmune thyroid disease evolution. In our study, all thyroid diseases were more frequent in women, especially in autoimmune thyroiditis, which female: male ratio was 9.7: 1. Females that represented 55 % of 1 000 cases were 88 % of autoimmune thyroid disease cases, and this difference was found also between elderly females of both samples. In the 1 000 patients, one of each 22 females presented clinical or subclinical chronic autoimmune thyroiditis. Forty percent of autoimmune thyroid disease cases referred familiar thyroid disease, particularly autoimmune, 3 cases had family history of systemic autoimmune disease and 17 % was associated with other autoimmune endocrine or systemic disease. Antithyroid antibody confirmation is sufficient proof for diagnosis, as was observed in 89 % of our cases. Permanent hypothyroidism is the most important functional consequence of chronic autoimmune thyroiditis,especially in older females, such as occurred in 55.5 % of 27 cases, 22.2 % as clinic hypothyroidism and 33.3 % as subclinic hypothyroidism. In 12 cases with normal thyroid function the mean age was 46.75±17,06 years, in 9 cases of subclinical hypothyroidism was 49,00±18,97 years and in 6 cases of clinical hypothyroidism 53,50±20,57 years. In chronic autoimmune thyroiditis, this progressive decline of thyroid function age-related, since normality toward increasing grades of hypothyroidism, is due to prolonged exposition of the thyroid to deleterious effects of inflammatory process. Although echosonographic findings are not specific in chronic autoimmune thyroiditis, they can orient the diagnosis and the fine needle aspiration biopsy in presence of solid nodules suspicious of malignancy. In our chronic autoimmune thyroiditis casuistic, most common echosonographic alterations were diffuse increase of thyroidal volume and heterogeneous echostructure; but also, 37.5 % of cases presented multiple micronodules iso or hypoechogenic, non palpable, therefore this significant frequency suggests a causal relation with chronic autoimmune thyroiditis.