[Correlation of ultrasound and radioisotope studies in subacute de Quervain thyroiditis]

The first report on ultrasonic findings in subacute thyroiditis was published in 1975 (1). More detailed studies combining ultrasonographic and clinical findings are still missing. The present paper compares echostructure of the thyroid gland with the level of hormones--triiodthyronine (T3), thyroxine (T4), thyroidstimulating hormone (TSH) and thyroglobulin (tg) and thyroglobulin autoantibodies (tg-ab).

This study included 30 patients with subacute thyroiditis de Quervain. The diagnosis was based on typical clinical symptoms, ultrasonic findings, metabolic test with J-131 uptake with thyroid scintiscan, level of hormones--T3, T4, TSH then tg and tg-ab and fine-needle aspiration biopsy of thyroid gland. The patients were followed-up for 6 months, i.e. from the onset of the disease until treatment. Every month the following tests were done: ultrasound of the thyroid gland ("real time" ultrasound with a 5 MHz linear transducer), hormones T3, T4, TSH, then tg and tg-at (original radioimunoassay "Vinca" and "Inep" Zemun).

During the acute phase of subacute thyroiditis pathological findings were detected by ultrasound in every patient. The gland increased in volume (p 0.05), unclear contours, nonhomogenous echostructure demonstrates in three ways: as hypodense with "pseudocysts", as hypodense, and multiple hypodense area, 6 months later, all patients had normal echostructure of the thyroid gland. In acute phase all patients had low J-131 uptake by the thyroid. Cytological findings of all patients refer to subacute thyroiditis. In the first 6 months the difference between hormone levels and echostructure of the gland is significant (p 0.05). The difference between tg-ab and echostructure of the gland is also significant. Only in the 6th month, there is no difference between these values (p 0.05). In acute phase, after 1 month and 6 months tg levels are not related to echostructure (p 0.05). The difference is significant in the period from the 2th to 6th month.

Changed ultrasonic findings in subacute thyroiditis have been described in literature. Although sonographic characteristics of the acute phase are well known, reports of long-term ultrasonic findings in subacute thyroiditis are rare (4,5). Ultrasonic findings are not uniform (6,10). They are in correlation with the form and phase of the disease. They may be related to the intensity of inflammation and edema seen in this disorder (11,12). Subacute thyroiditis is followed by hormonal dysbalance, increase of tg level and tg-ab occurrence (3). Recovery is associated with a return to normal functional and ultrasonic characteristics of the thyroid gland (2). By comparing levels of hormones, tg and tg-ab with the ultrasonic findings it can be noted that the thyroid gland has been recovering functionally more than morphologically. Subacute thyroiditis does not cause ultrasonically visible changes in parenchyma of the thyroid gland.

In serial examinations no correlation was found between sonographic findings and hormone levels (T3, T4, TSH) as in sonographic findings and tg-in acute phase of disease, only in convalescence period. Correlation was found between sonographic findings and tg in acute phase and convalescence period of disease. Ultrasonography provides useful information for follow-up of the course of disease.