Abstract
OBJECTIVE: To study the relationship between the pattern of the hypoechoic area at diagnosis,the length of time from onset to diagnosis, the course of treatment and the prognosis of subacute thyroiditis.
PATIENTS AND METHODS: We analyzed ultrasonographic findings and thyroid function before and after treatment in 165 patients diagnosed with subacute thyroiditis treated with corticosteroids between February 2008 and July 2021.
RESULTS AND DISCUSSION: The median time from onset to diagnosis was 19 days (first to third quartiles: 12-30 days). At diagnosis, 129 patients had hypoechoic areas in bilateral lobes (bilateral group), 35 patients in unilateral lobes (unilateral group), and in 1 patient it was difficult to determine.The mean times from onset to diagnosis were 21 days (13-31 days) in the bilateral group and 14 days (10-20 days) in the unilateral group (P=0.009). Creeping was observed in 71.0％ of patients in the unilateral group. Dose escalation during prednisolone tapering and redosing after discontinuation of prednisolone were required in 10.9％ of patients in the bilateral group and 40.0％ in the unilateral group (P<0.001). After healing, subclinical or overt hypothyroidism persisted in 20.8％ of the patients in the bilateral group and 28.6％ of those in the unilateral group (P=0.36). The mean times from onset to diagnosis were 19.5 days (13-33 days) in the persistent hypothyroid group and 19.5 days (12-30) in the group that recovered normal thyroid function(P=0.77).
CONCLUSIONS: Patients with hypoechoic areas limited to a unilateral lobe at diagnosis are more likely to be in the early course of the disease and caution should be employed against creeping phenomena during treatment and relapse with prednisolone dose reduction. The number of days from onset to diagnosis and the pattern of the hypoechoic area at diagnosis do not correlate with the prognosis of thyroid function after healing of subacute thyroiditis.
