Differential diagnosis of thyrotoxicosis

Abstract

Hyperthyroidism is characterized by increased thyroid hormone synthesis and secretion from the thyroid gland, whereas thyrotoxicosis refers to the clinical syndrome of excess circulating thyroid hormones, irrespective of the source. Thyrotoxicosis is characterized by low serum thyroid-stimulating hormone (TSH) level and elevated serum levels of free thyroxine or free triiodothyronine, or both. Therefore, thyrotoxicosis is divided into two subtypes: Thyrotoxicosis with hyperthyroidism such as Graves’ disease and Plummer’s disease, and thyrotoxicosis without hyperthyroidism such as painless and subacute thyroiditis. Here, I describe the differential diagnosis of hyperthyroidism; differentiation between Graves’ disease and Plummer’s disease; differentiation between Graves’ disease with and without thyroid storm. Further, I show the differentiation among Graves’ disease, painless thyroiditis and subacute thyroiditis. I believe that the proper diagnosis leads to appropriate treatment and management of thyrotoxicosis.