Clinical Characteristics of 852 Patients with Subacute Thyroiditis Before Treatment

Objective: Subacute thyroiditis (SAT) is a transient inflammatory disease of the thyroid. We evaluated the clinical characteristics based on laboratory and imaging studies in patients with SAT before treatment.

Patients: We reviewed the medical records of 852 patients (107 men and 745 women) with SAT who visited our thyroid clinic at Kuma Hospital from 1996 through 2004.

Results: SAT developed most often in female patients aged 40 to 50 years, with significant seasonal clusters during summer to early autumn. While the rates of any virus infections and diseases did not differ from those in the general population, recurrent episodes of SAT at intervals of 13.6+/-5.6 years accounted for 1.6% of all cases. At the onset of SAT, 28.2% of patients had temperatures greater than 38 degrees C and typical symptoms associated with thyrotoxicosis developed in more than 60% of patients. Before treatment, most of the abnormal laboratory findings associated with thyrotoxicosis, inflammation, and liver dysfunction reached peak levels within 1 week after onset. Ultrasound examination showed that half of the patients with unilateral thyroid pain presented with bilateral hypoechogenic area in the thyroid and the rate of bilateral hypoechogenic area tended to increase 2 months after onset.

Conclusion: Laboratory studies of thyroid dysfunction and inflammation related to SAT presented peak levels within 1 week after onset.