Initial [99m]Tc thyroidal kinetics in thyrotoxicosis: patterns and usefulness in differential diagnosis of toxic nodular goiter

This prospective study included 74 untreated hyperthyroid patients as well as 25 age- matched healthy controls aiming at assessment of initial Tc 99m thyroidal kinetics' patterns in different types of thyrotoxicosis, its usefulness in differential diagnosis of toxic nodular goiter, mainly discrimination between its immune and non-immune variants, compared to CDFS and to find-out which of the parameters evaluated was the best in such issue. Patients were selected and divided into four groups according to their definitive diagnosis based on clinical laboratory data, sonography and Tc 99m static thyroid scan. Group I: included 23 patients with Graves ' disease, group 2 : included 26 patients with toxic nodular goiter, group 3: included 10 patients with single toxic adenoma, group 4-.included 15 patients with thyroiditis. All patients,except group 4 patients, had statistically significant higher FI values compared to control subjects [p<0.05]. Moreover, group 1 and 4 patients [cases with immune thyrotoxicosis] showed statistically significant higher PI values compared to other groups [non-immune thyrotoxic patients] as well as control group [p<0.05].Group 1 and group 4 patients showed almost similar PI values [p>0.05]. Also, group 2 and 3 showed almost similar PI and FI values [p >0.05]. Retrospective analysis of PI and FI values of group 2 patients [toxic nodular goiter] revealed different behaviour of their PI values. Cases with immune variants of toxic nodular goiter had higher PI values than non-immune variants [p< 0.0001] despite their almost similar FI values and hormonal levels. Regarding the sensitivity and specificity, PI showed statistically significant higher values than those of CDFS in differentiating immune from non-immune variants of toxic nodular goiters [p<0.002 and <0.0003 respectively]. our results suggest that initial Tc 99m thyroidal kinetics done as a part of the routinely done static thyroid scan is an objective, non-invasive simple methods that can be useful in discrimination between immune and non-immune variants of toxic nodular goiter with better sensitivity and specificity than CDFS

Thyroid dysfunction in type 2 diabetes

The association between diabetes mellitus and thyroid disorders was always a matter of medical interest. The explanation of that association is still debatable whether through metabolic, immune, vascular or multifactorial. The aim of the present study was to identify subjects at risk of clinical or subclinical thyroid dysfunction by other investigation modalities in diabetics. Forty seven type 2 diabetic patients 21 men and 26 women with age xx ranging from 40-70 years and 20, age, sex and weight matched healthy control subjects were subjected to: estimation of fasting, postprandial plasma glucose. Estimation of serum free T3 and T4 and TSH by radioimmunoassay. Thyroid scan dynamic and static using technetium[99m]. Thyroid colour coded duplex Doppler study of the inferior thyroid arteries. Exclusion criteria included drugs that interfere with thyroid functions. As regards Technetium thyroid scan: the perfusion index [PERI] was significantly higher in patients compared to control subjects [p-value < 0.009]. A negative correlation was found between the duration of DM and the functional index which was statistically significant in diabetic women [r = -0.4264, p=0.03]. Thirty percent of patients were detected to have dynamic thyroid scan characteristics of thyroiditis with marked increase of the perfusion index, marked decrease of the functional index till zero and replacement of slope II and III with a plateau. As regard duplex Doppler Results: the mean pulsatility [PI] and resistivity [RI] indices were found to be higher in patients with thyroiditis [as evident by thyroid scan]. The peak systolic, diastolic, end diastolic and mean velocities where statistically lower in those patients compared to control. The mean value of pulsatility and resistivity indices were significantly higher in patients with subclinical hypothyroid state than control subjects, whereas, thyroid gland volume, blood flow and blood velocities showed no statistically significant difference. Tc[99m] dynamic thyroid scan and duplex Doppler sonography detected hypofunction and abnormal perfusion while the thyroid hormones were still on the low normal side. So, it is recommended to use these investigation tools in following up patients with long standing diabetes specially in those who show clinical or laboratory evidence of thyroiditis, [such as neck pain, thyroid swelling or elevated ESR]. A condition which is not uncommon in patients with Type 2 diabetes