Graves Disease: A common form of hyperthyroidism with a diffuse hyperplastic GOITER. It is an autoimmune disorder that produces antibodies against the THYROID STIMULATING HORMONE RECEPTOR. These autoantibodies activate the TSH receptor, thereby stimulating the THYROID GLAND and hypersecretion of THYROID HORMONES. These autoantibodies can also affect the eyes (GRAVES OPHTHALMOPATHY) and the skin (Graves dermopathy).Antithyroid Agents: Agents that are used to treat hyperthyroidism by reducing the excessive production of thyroid hormones.Immunoglobulins, Thyroid-Stimulating: Autoantibodies that bind to the thyroid-stimulating hormone (TSH) receptor (RECEPTORS, THYROTROPIN) on thyroid epithelial cells. The autoantibodies mimic TSH causing an unregulated production of thyroid hormones characteristic of GRAVES DISEASE.Methimazole: A thioureylene antithyroid agent that inhibits the formation of thyroid hormones by interfering with the incorporation of iodine into tyrosyl residues of thyroglobulin. This is done by interfering with the oxidation of iodide ion and iodotyrosyl groups through inhibition of the peroxidase enzyme.Receptors, Thyrotropin: Cell surface proteins that bind pituitary THYROTROPIN (also named thyroid stimulating hormone or TSH) and trigger intracellular changes of the target cells. TSH receptors are present in the nervous system and on target cells in the thyroid gland. Autoantibodies to TSH receptors are implicated in thyroid diseases such as GRAVES DISEASE and Hashimoto disease (THYROIDITIS, AUTOIMMUNE).Thyroid Gland: A highly vascularized endocrine gland consisting of two lobes joined by a thin band of tissue with one lobe on each side of the TRACHEA. It secretes THYROID HORMONES from the follicular cells and CALCITONIN from the parafollicular cells thereby regulating METABOLISM and CALCIUM level in blood, respectively.Thyroiditis, Autoimmune: Inflammatory disease of the THYROID GLAND due to autoimmune responses leading to lymphocytic infiltration of the gland. It is characterized by the presence of circulating thyroid antigen-specific T-CELLS and thyroid AUTOANTIBODIES. The clinical signs can range from HYPOTHYROIDISM to THYROTOXICOSIS depending on the type of autoimmune thyroiditis.Propylthiouracil: A thiourea antithyroid agent. Propythiouracil inhibits the synthesis of thyroxine and inhibits the peripheral conversion of throxine to tri-iodothyronine. It is used in the treatment of hyperthyroidism. (From Martindale, The Extra Pharmacopeoia, 30th ed, p534)Graves Ophthalmopathy: An autoimmune disorder of the EYE, occurring in patients with Graves disease. Subtypes include congestive (inflammation of the orbital connective tissue), myopathic (swelling and dysfunction of the extraocular muscles), and mixed congestive-myopathic ophthalmopathy.Carbimazole: An imidazole antithyroid agent. Carbimazole is metabolized to METHIMAZOLE, which is responsible for the antithyroid activity.Thyrotoxicosis: A hypermetabolic syndrome caused by excess THYROID HORMONES which may come from endogenous or exogenous sources. The endogenous source of hormone may be thyroid HYPERPLASIA; THYROID NEOPLASMS; or hormone-producing extrathyroidal tissue. Thyrotoxicosis is characterized by NERVOUSNESS; TACHYCARDIA; FATIGUE; WEIGHT LOSS; heat intolerance; and excessive SWEATING.Hashimoto Disease: Chronic autoimmune thyroiditis, characterized by the presence of high serum thyroid AUTOANTIBODIES; GOITER; and HYPOTHYROIDISM.Exophthalmos: Abnormal protrusion of both eyes; may be caused by endocrine gland malfunction, malignancy, injury, or paralysis of the extrinsic muscles of the eye.Thyroiditis, Subacute: Spontaneously remitting inflammatory condition of the THYROID GLAND, characterized by FEVER; MUSCLE WEAKNESS; SORE THROAT; severe thyroid PAIN; and an enlarged damaged gland containing GIANT CELLS. The disease frequently follows a viral infection.Thyroxine: The major hormone derived from the thyroid gland. Thyroxine is synthesized via the iodination of tyrosines (MONOIODOTYROSINE) and the coupling of iodotyrosines (DIIODOTYROSINE) in the THYROGLOBULIN. Thyroxine is released from thyroglobulin by proteolysis and secreted into the blood. Thyroxine is peripherally deiodinated to form TRIIODOTHYRONINE which exerts a broad spectrum of stimulatory effects on cell metabolism.Myxedema: A condition characterized by a dry, waxy type of swelling (EDEMA) with abnormal deposits of MUCOPOLYSACCHARIDES in the SKIN and other tissues. It is caused by a deficiency of THYROID HORMONES. The skin becomes puffy around the eyes and on the cheeks. The face is dull and expressionless with thickened nose and lips.Thyroiditis: Inflammatory diseases of the THYROID GLAND. Thyroiditis can be classified into acute (THYROIDITIS, SUPPURATIVE), subacute (granulomatous and lymphocytic), chronic fibrous (Riedel's), chronic lymphocytic (HASHIMOTO DISEASE), transient (POSTPARTUM THYROIDITIS), and other AUTOIMMUNE THYROIDITIS subtypes.Thyrotropin: A glycoprotein hormone secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Thyrotropin stimulates THYROID GLAND by increasing the iodide transport, synthesis and release of thyroid hormones (THYROXINE and TRIIODOTHYRONINE). Thyrotropin consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the pituitary glycoprotein hormones (TSH; LUTEINIZING HORMONE and FSH), but the beta subunit is unique and confers its biological specificity.Thyroid Function Tests: Blood tests used to evaluate the functioning of the thyroid gland.Autoantibodies: Antibodies that react with self-antigens (AUTOANTIGENS) of the organism that produced them.Hyperthyroidism: Hypersecretion of THYROID HORMONES from the THYROID GLAND. Elevated levels of thyroid hormones increase BASAL METABOLIC RATE.Thyroidectomy: Surgical removal of the thyroid gland. (Dorland, 28th ed)Thyroid Diseases: Pathological processes involving the THYROID GLAND.Goiter, Nodular: An enlarged THYROID GLAND containing multiple nodules (THYROID NODULE), usually resulting from recurrent thyroid HYPERPLASIA and involution over many years to produce the irregular enlargement. Multinodular goiters may be nontoxic or may induce THYROTOXICOSIS.ThyroglobulinTriiodothyronine: A T3 thyroid hormone normally synthesized and secreted by the thyroid gland in much smaller quantities than thyroxine (T4). Most T3 is derived from peripheral monodeiodination of T4 at the 5' position of the outer ring of the iodothyronine nucleus. The hormone finally delivered and used by the tissues is mainly T3.Goiter: Enlargement of the THYROID GLAND that may increase from about 20 grams to hundreds of grams in human adults. Goiter is observed in individuals with normal thyroid function (euthyroidism), thyroid deficiency (HYPOTHYROIDISM), or hormone overproduction (HYPERTHYROIDISM). Goiter may be congenital or acquired, sporadic or endemic (GOITER, ENDEMIC).Iodine Radioisotopes: Unstable isotopes of iodine that decay or disintegrate emitting radiation. I atoms with atomic weights 117-139, except I 127, are radioactive iodine isotopes.Thyroid Hormones: Natural hormones secreted by the THYROID GLAND, such as THYROXINE, and their synthetic analogs.Iodide Peroxidase: A hemeprotein that catalyzes the oxidation of the iodide radical to iodine with the subsequent iodination of many organic compounds, particularly proteins. EC Crisis: A dangerous life-threatening hypermetabolic condition characterized by high FEVER and dysfunction of the cardiovascular, the nervous, and the gastrointestinal systems.Hypothyroidism: A syndrome that results from abnormally low secretion of THYROID HORMONES from the THYROID GLAND, leading to a decrease in BASAL METABOLIC RATE. In its most severe form, there is accumulation of MUCOPOLYSACCHARIDES in the SKIN and EDEMA, known as MYXEDEMA.Orbit: Bony cavity that holds the eyeball and its associated tissues and appendages.Long-Acting Thyroid Stimulator: An immunoglobulin G, often found in the blood of hyperthyroid individuals. It stimulates the thyroid for a longer duration than does thyrotoxin and may cause hyperthyroidism in newborns due to placental transmission.Thyroid Neoplasms: Tumors or cancer of the THYROID GLAND.Iodine: A nonmetallic element of the halogen group that is represented by the atomic symbol I, atomic number 53, and atomic weight of 126.90. It is a nutritionally essential element, especially important in thyroid hormone synthesis. In solution, it has anti-infective properties and is used topically.Sodium Pertechnetate Tc 99m: A gamma-emitting radionuclide imaging agent used for the diagnosis of diseases in many tissues, particularly in the gastrointestinal system, cardiovascular and cerebral circulation, brain, thyroid, and joints.Grave Robbing: Stealing of corpses after burial, especially for medical dissection. In the late 18th and early 19th centuries, in the absence of laws governing the acquisition of dissecting material for the study of anatomy, the needs of anatomy classes were met by surreptitious methods: body-snatching and grave robbing. (Random House Unabridged Dictionary, 2d ed; from Garrison, An Introduction to the History of Medicine, 4th ed, p447; from Castiglioni, A History of Medicine, 2d ed, p676)Autoimmune Diseases: Disorders that are characterized by the production of antibodies that react with host tissues or immune effector cells that are autoreactive to endogenous peptides.Eye Diseases: Diseases affecting the eye.Oculomotor Muscles: The muscles that move the eye. Included in this group are the medial rectus, lateral rectus, superior rectus, inferior rectus, inferior oblique, superior oblique, musculus orbitalis, and levator palpebrae superioris.Thyroid Dysgenesis: Defective development of the THYROID GLAND. This concept includes thyroid agenesis (aplasia), hypoplasia, or an ectopic gland. Clinical signs usually are those of CONGENITAL HYPOTHYROIDISM.Hypocalcemia: Reduction of the blood calcium below normal. Manifestations include hyperactive deep tendon reflexes, Chvostek's sign, muscle and abdominal cramps, and carpopedal spasm. (Dorland, 27th ed)