Resumen

SANCHEZ -VASQUEZ, Raúl; SANCHEZ ROBLES, Raúl  y  BISSO ZOLLNER, Adolfo. Influencia de la relación "área nodular / área parenquimal" en la conversión de nódulo tiroideo autónomo compensado (NAC) a descompensado (NAD). Rev Med Hered [online]. 2003, vol.14, n.1, pp.26-35. ISSN 1018-130X.

Objective: Since the TSH theory of inhibition via nodular hormonal secretion does not explain satisfactorily the presence of iodine at the parenchymal level (NAC), neither its absence in the gammagraphic scans in the NAD stage, we studied the possible role of the relationship "nodular area / parenchymal area" and its effect in the presence and/or absecense of iodine uptake by the parenchyma in these gammagraphic stages. Material and methods: One hundred cases of autonomous thyroid nodules were studied. They were divided in two groups: 75 cases of compensated autonomous nodules (NAC) and 25 cases of descompensated autonomous nodules (NAD) with an average age of 48.8 years and a female to male ratio of 10:1. Results: There was no difference between the parenchymal areas in both groups: (p< 0.821, non significant). We did find a difference between the nodular areas in both groups: (NAC: 4.62 cm²), (NAD: 16.14 cm²), as well as a highly significant difference in the quotient (NAC: 0.13), (NAD: 0.49) relationship of the "nodular/parenchymal areas" i.e. p< 0.0001. Conclusions: The analysis of the correlation gave us significant results in both groups: p< 0.001, and the analysis of regression by Fisher test showed a significant direct positive lineal relationship. The analysis of these results allows us to raise the hypothesis that in the evolution from NAC to NAD, both with similar parenchymal areas, the nodular areas are smaller in NAC and remarkably larger in NAD, and that the relation of the area "nodule/parenchyma" plays an important role in the presence and/or absence of radioactive iodine uptake in the paranodular parenchyma (NAC-NAD). This uptake of radioactive iodine is independent of the suppression of TSH, and is rather related to the degree of parenchymal saturation of iodine originated in the slow intrathyroidal metabolism, conditioned by high levels of thyroid circulating hormone, coming from the autonomous nodules. When the relationship "nodular/parenquimal areas" activity reaches a critical level the NAC becomes NAD. (Rev Med Hered 2003; 14:266-35).

Palabras clave : Euthyroidism; hyperthyroidism; automous nodules; TSH test; T3 test; thyroid gammagraphic scan.

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