Percentage of immature granulocytes in subacute thyroiditis follow-up and differential diagnosis with Graves? disease

Aim: Graves' disease (GD) and subacute thyroiditis (SAT) are common causes of thyrotoxicosis. Although the presence of neck pain is helpful in the differential diagnosis of these two entities some cases of SAT may have an atypical painless presentation. In recent years, the number of patients with painless SAT has been increasing in the literature and sometimes this may cause difficulties in differential diagnosis. Thus, auxiliary parameters other than clinical findings are needed for the correct diagnosis. In our study, we aimed to evaluate the immature granulocyte percentage (IG%), which is a new marker of acute inflammation, in the differential diagnosis of SAT, which is an inflammatory condition, and GD. Material and Methods: In this study, data from 59 patients diagnosed with GD and 59 patients with SAT in the Endocrinology and Metabolic Diseases Outpatient Clinic of a tertiary medical care center, between January 2017 and October 2021 were retrospectively analyzed. Pre-treatment clinical and laboratory data obtained from patients who were diagnosed with SAT or GD were analyzed, IG% were recorded. The IG% were re-evaluated in patients after treatment. Results: Pre-treatment IG% was found to be significantly higher in the SAT group when compared GD group. There was a significant decrease in IG% after treatment in SAT. In addition, steroid need was higher in patients with high IG% in the SAT group. Discussion: Our study showed that IG% may be a helpful parameter in the differential diagnosis of GD and SAT and in predicting the need for steroids in SAT patients early.