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.

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“…Ultrasonography and computed tomography (CT) have proven to be very successful methods in identifying thyroid nodules, while thyroid scintigraphy with iodine 123 (J-123), iodine 131 (J-131), and (99m) Tcpertechnetate is used to determine the functional state of thyroid gland and nodes in thyroid gland [7]. In cases of thyrotoxicosis with hyperthyroidism (GB disease, TMG, and TA), high activity of radioactive iodine uptake in thyroid gland is observed, while in cases of thyrotoxicosis without hyperthyroidism (generally in the cases of thyroiditis), when thyrotoxicosis is caused by a release of preformed thyroid hormones into the circulation, the uptake activity of radioactive iodine in thyroid gland is low [8]. Scintigraphy of thyroid gland with (99m) Tc pertechnetate has been shown to be an efficacious method in distinguishing hyperthyroidism from thyrotoxicosis due to the properties that Pertechnetate ions TcO4 − behave similarly to iodide ions and are actively transported in thyroid gland by the sodium iodide symporter of thyroid follicular cells [9].…”

Longitudinal changes in an autonomously functioning thyroid nodule with coexisting follicular thyroid carcinoma over 14 years

“…Autonomously functioning thyroid nodule (AFTN) accounts for 0.3% of hyperthyroidism cases, and it comprises 0.5–0.8% of all thyroid nodules [ 1 ]. Amelioration of hyperthyroidism in patients with AFTN is achieved by thyroidectomy, anti-thyroid drugs, radioactive iodide (RAI), percutaneous ethanol injection therapy or radiofrequency ablation.…”