Hyperthyroidism classification

Hyperthyroidism Microchapters
Patient Information
Overview
Classification
Differentiating hyperthyroidism from other diseases
Pathophysiology

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Farman Khan, MD, MRCP [2]

Classification

• Graves' disease: An autoimmune disorder resulting from thyroid-stimulating immunoglobulins, which stimulate thyroid gland growth and hormone synthesis. It's prominent features, including pretibial myxedema and ophthalmopathy, are autoimmune in origin. Graves' disease is the most common cause of hyperthyroidism. High iodine intake and stressful events may be risk factors.

• Toxic adenoma and toxic multinodular goiter: It results from focal or diffuse hyperplasia of thyroid follicular cells which are independent of regulation by TSH. Activating somatic mutations of the genes for the TSH receptor have been found in both of these. Mutations of the TSH-receptor gene are most common; they were found in 15 of 31 toxic adenomas in one study.

• Hashitoxicosis: It has two phases, initially it presents with hyperthyroidism and a high radioiodine uptake caused by TSH-receptor antibodies. This is followed by infiltration of the gland with lymphocytes resulting in autoimmune-mediated destruction of thyroid tissue leading to the development of hypothyroidism.

• Iodine-induced hyperthyroidism: Develop after an iodine load or iodine-rich drugs such as amiodarone.

• TSH-mediated hyperthyroidism: It is because of increased TSH production. It has two forms, neoplastic and non-neoplastic. Neoplastic includes TSH-producing pituitary adenoma. Almost all of these patients have a goiter, 40 percent have defects in their field of vision, and one-third of women have galactorrhea. All patients have high serum thyroid hormone concentrations. Non-neoplastic TSH-mediated hyperthyroidism is due to resistance of the effect of thyroid hormone on pituitary TSH.

• Trophoblastic disease and germ cell tumors: Hyperthyroidism can occur in women with a hydatidiform mole or choriocarcinoma and in men with testicular germ cell tumors.