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The following is a summary of  “Atypical clinical courses of Graves’ disease confound differential diagnosis of hyperthyroidism,” published in the December 8, 2023 online issue of the Journal of Nippon Medical School.

For an investigation, researchers assessed the suitability of the existing framework for distinguishing painless thyroiditis from Graves’ disease (GD) in individuals experiencing thyrotoxicosis. They conducted a retrospective analysis of the clinical trajectories of 343 consecutive hyperthyroid patients diagnosed through Tc-99m pertechnetate thyroid uptake (TcTU) testing at their institution from January 2011 to December 2017. Among the 263 patients exhibiting normal or elevated TcTU levels (≥1.0%), 255 (97%) were definitively identified as having GD, whereas five experienced spontaneous remission GD or exhibited atypical GD. Among the 10 patients with low TcTU levels (<1.0% and ≥0.5%), seven had GD, with the remainder presenting subclinical GD, spontaneous remission GD followed by relapse, or painless thyroiditis. In cases with very low TcTU levels (<0.5%), the majority had thyroiditis (painless thyroiditis, 33/67 [49%]; subacute thyroiditis, 29/67 [43%]), and some tested positive for anti-TSH receptor antibodies. Given the potential confounding influence of atypical GD on thyrotoxicosis diagnoses, it is imperative to monitor patients with a provisional diagnosis, irrespective of the condition. This study is the first to conclusively indicate the absence of a gold standard for GD diagnosis. Consequently, it is urgent to establish a consensus on GD definition to facilitate determining the specificity and sensitivity of forthcoming diagnostic assessments.

Source: https://dx.doi.org/10.1272/jnms.JNMS.2024_91-104