The prevalence and significance of nonuniform thyroid radio‐isotope uptake in patients with Graves’ disease

Abstract

Objective To evaluate the prevalence and clinical significance of nonuniform technetium (99mTc) uptake among patients with Graves’ disease (GD). Design, Patients and Measurements Patients with GD, referred between July 2005 and March 2018, had Tc99‐ uptake scans and TSH‐receptor antibody (TRAb) measured before antithyroid drug (ATD) therapy. Risk of relapse after ATD cessation was monitored until June 2021 and compared between GD patients based on uptake patterns. Results Of the 276 GD patients (mean age, 49.8 years; 84% female), 25 (9.0%) had nonuniform Tc99 uptake. At diagnosis, individuals with nonuniform uptake were older (mean age of 61.8 vs. 48.5 years, p < .001), had lower mean thyroid hormone levels (free thyroxine: 36.3 vs. 45.4 pmol/L, p = .04 and free triiodothyronine: 10.0 vs. 17.8 pmol/L, p < .001) and median TRAb levels (4.2 vs. 6.6 U/L, p = .04) compared with those with a uniform uptake. Older age was a significant predictor for the presence of nonuniform uptake in GD patients; odds ratio (95% confidence intervals) of 1.07 (1.03 – 1.10). The risk of relapse was similar in both groups after a median (IQR) follow‐up of 41 (13–74) months after ATD cessation (56.0% vs. 46.3%, respectively); hazard ratio (95% confidence intervals) of 1.74 (0.96–3.15). Conclusions Nonuniform radio‐isotope uptake is seen in 1 in 11 patients with GD which could be misdiagnosed as toxic multinodular goitre if TRAb levels are not measured. Treatment of GD patients with nonuniform radio‐isotope uptake with ATD therapy as first‐line appears to be equally effective as compared with those with uniform uptake. TRAb testing should be the main diagnostic test for patients with suspected GD with radio‐labelled uptake scans being reserved for those who are TRAb negative.

Measurement of TPO Ab and TG Ab levels and its association with thyroid dysfunction in Graves’ disease patients in Najaf city

“…Additionally, Abdalaziz stated that the low TSH in GD is due to the surge in thyroid hormones. [18]. As shown in figure (3), the triiodothyronine (T3) hormone's mean and standard deviation for the patient and control groups were 4.65 ±1.36 and 2.15 ±0.57, respectively.…”