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Hyperthyroidism Overview

Hyperthyroidism refers to any condition in which there is too much thyroid hormone in the body. It is sometimes referred to as overactive thyroid. Excess thyroid hormone levels can increase metabolism (how energy is used), and increase the risk of other health issues such as heart disease, bone loss, and problems during pregnancy.

Hyperthyroidism Causes

Common causes of hyperthyroidism in adults include:

  • Diffuse Toxic Goiter (Graves' Disease)
    • Overactivity of the entire thyroid gland caused by antibodies in the blood which stimulate the thyroid to grow and secrete excessive amounts of thyroid hormone
  • Toxic Adenoma ("hot nodule")
    • A dominant thyroid nodule, or lump, is overactive and secretes excess thyroid hormone
  • Toxic Multinodular Goiter (Plummer's disease)
    • One or more nodules or lumps in the thyroid becomes overactive
  • Subacute Thyroiditis
    • Hyperthyroid phase of subacute thyroiditis, caused by viral infection or postpartum inflammatory process
    • Due to thyroid inflammation, excess hormone is released into the blood circulation
    • More than 90% of affected individuals will go back to normal thyroid function without treatment.
  • Drug-Induced Hyperthyroidism
    • Iodine-induced hyperthyroidism: older population, typically in setting of preexisting nontoxic nodular goiter
    • amiodarone (Cordarone)
    • Iodine-containing contrast material used in radiology studies
Medically Reviewed by a Doctor on 11/10/2014
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Thyroidectomy (Thyroid Surgery) Definition

Thyroidectomy: The surgical removal of part or all of the thyroid gland.

Subtotal thyroidectomy, the more commonly performed operation, involves removal of only a part of the gland. This procedure may be done to:

  • Remove a tumor from the thyroid,
  • Reduce the mass of a goitrous (enlarged) thyroid gland, or
  • Treat hyperthyroidism (excess production of thyroid hormone).

The goal in the case of hyperthyroidism is to leave just enough thyroid tissue to make a normal amount of thyroid hormone. If too much thyroid is removed, the patient will produce too little thyroid hormone (hypothyroidism) and need treatment to return the thyroid status to normal (euthyroid) status. The possible complications of thyroid surgery include vocal cord paralysis and accidental removal of the parathyroid glands (located behind the thyroid gland), resulting in low calcium levels (the parathyroid glands regulate calcium).

Subtotal thyroidectomy is appropriate in some people with hyperthyroidism, especially those with a large goiter, and it may also be indicated in cases with a coexistent thyroid nodule whose nature is unclear. The patient is treated with an antithyroid drug until euthyroidism has been achieved and inorganic iodide is also usually administered for seven days before surgery to "cool down" the overactive thyroid gland. In surgical centers with the most experience, hyperthyroidism is cured in more than 98% of cases with low rates of complications. Surgery is more costly than nonsurgical therapy of hyperthyroidism (with an antithyroid drug or radioactive iodine).

SOURCE: Thyroidectomy.

Read What Your Physician is Reading on Medscape

Hyperthyroidism »

Thyrotoxicosis is the hypermetabolic condition associated with elevated levels of free thyroxine (FT4), free triiodothyronine (FT3), or both.

Read More on Medscape Reference »

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