Clinical Aspects of Thyrotoxicosis in 592 Patients: A Single Center Experience from Turkey

Purpose: To determine the main causes of thyrotoxicosis and to compare the clinical and biochemical fetaures of the patients according to the underlying cause of thyrotoxicosis.\udMaterial and Method: Five hundred ninety-two patients, who were consecutively diagnosed with thyrotoxicosis, were retrospectively analysed. Symptoms of thyrotoxicosis, serum thyroid-stimulating hormone (TSH), free T3 and free T4 levels, anti-thyroglobulin autoantibody (TGAb), anti-thyroid peroxidase autoantibody (TPOAb) and ultrasonographic features were recorded. To determine the cause of thyrotoxicosis, Tc-99m pertechnetate thyroid scintigraphy was performed in all patients except for pregnant women. The clinical and biochemical results were compared between the patients with different diagnosis of thyrotoxicosis.\udResults: 40.9% of patients were diagnosed with toxic multinodular goiter (TMNG). The other main causes of thyrotoxicosis were: Graves’ disease (GD) (22%), thyroiditis (14.8%), gestational thyrotoxicosis (12.7%), and toxic adenoma (9.6%). The clinical presentation and severity of thyrotoxicosis varied according to the underlying cause. Weight loss was more frequently observed in patients with GD (p=0.0001), while cardiac arrhythmia dominated in patients with TMNG (p=0.0001). Moderate (27%) or severe (23.9%) thyrotoxicosis was more common in patients with GD than in patients with other forms of thyrotoxicosis (p=0.0001).\udDiscussion: Toxic multinodular goiter is the most common cause of thyrotoxicosis in our region