Hyperthyroidism

Not to be confused with Hyperthyroxinemia or Hypothyroidism.

Hyperthyroidism
Other namesOveractive thyroid, hyperthyreosis
Triiodothyronine (T3, pictured) and thyroxine (T4) are both forms of thyroid hormone.
SpecialtyEndocrinology
SymptomsIrritability, muscle weakness, sleeping problems, fast heartbeat, heat intolerance, diarrhea, enlargement of the thyroid, weight loss[1]
ComplicationsThyroid storm[2]
Usual onset20–50 years old[2]
CausesGraves' disease, multinodular goiter, toxic adenoma, inflammation of the thyroid, eating too much iodine, too much synthetic thyroid hormone[1][2]
Diagnostic methodBased on symptoms and confirmed by blood tests[1]
TreatmentRadioiodine therapy, medications, thyroid surgery[1]
MedicationBeta blockers, methimazole[1]
Frequency1.2% (US)[3]
DeathsRare directly, unless thyroid storm occurs; associated with increased mortality if untreated (1.23 HR)[4]

Hyperthyroidism is the condition that occurs due to excessive production of thyroid hormones by the thyroid gland.[3] Thyrotoxicosis is the condition that occurs due to excessive thyroid hormone of any cause and therefore includes hyperthyroidism.[3] Some, however, use the terms interchangeably.[5] Signs and symptoms vary between people and may include irritability, muscle weakness, sleeping problems, a fast heartbeat, heat intolerance, diarrhea, enlargement of the thyroid, hand tremor, and weight loss.[1] Symptoms are typically less severe in the elderly and during pregnancy.[1] An uncommon but life-threatening complication is thyroid storm in which an event such as an infection results in worsening symptoms such as confusion and a high temperature; this often results in death.[2] The opposite is hypothyroidism, when the thyroid gland does not make enough thyroid hormone.[6]

Graves' disease is the cause of about 50% to 80% of the cases of hyperthyroidism in the United States.[1][7] Other causes include multinodular goiter, toxic adenoma, inflammation of the thyroid, eating too much iodine, and too much synthetic thyroid hormone.[1][2] A less common cause is a pituitary adenoma.[1] The diagnosis may be suspected based on signs and symptoms and then confirmed with blood tests.[1] Typically blood tests show a low thyroid stimulating hormone (TSH) and raised T3 or T4.[1] Radioiodine uptake by the thyroid, thyroid scan, and measurement of antithyroid autoantibodies (thyroidal thyrotropin receptor antibodies are positive in Graves disease) may help determine the cause.[1]

Treatment depends partly on the cause and severity of disease.[1] There are three main treatment options: radioiodine therapy, medications, and thyroid surgery.[1] Radioiodine therapy involves taking iodine-131 by mouth which is then concentrated in and destroys the thyroid over weeks to months.[1] The resulting hypothyroidism is treated with synthetic thyroid hormone.[1] Medications such as beta blockers may control the symptoms, and anti-thyroid medications such as methimazole may temporarily help people while other treatments are having an effect.[1] Surgery to remove the thyroid is another option.[1] This may be used in those with very large thyroids or when cancer is a concern.[1] In the United States hyperthyroidism affects about 1.2% of the population.[3] Worldwide, hyperthyroidism affects 2.5% of adults.[8] It occurs between two and ten times more often in women.[1] Onset is commonly between 20 and 50 years of age.[2] Overall the disease is more common in those over the age of 60 years.[1]

  1. ^ a b c d e f g h i j k l m n o p q r s t u v "Hyperthyroidism". www.niddk.nih.gov. July 2012. Archived from the original on 4 April 2015. Retrieved 2 April 2015.
  2. ^ a b c d e f Devereaux D, Tewelde SZ (May 2014). "Hyperthyroidism and thyrotoxicosis". Emergency Medicine Clinics of North America. 32 (2): 277–292. doi:10.1016/j.emc.2013.12.001. PMID 24766932.
  3. ^ a b c d Bahn Chair RS, Burch HB, Cooper DS, Garber JR, Greenlee MC, Klein I, et al. (June 2011). "Hyperthyroidism and other causes of thyrotoxicosis: management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists". Thyroid. 21 (6): 593–646. doi:10.1089/thy.2010.0417. PMID 21510801.
  4. ^ Lillevang-Johansen M, Abrahamsen B, Jørgensen HL, Brix TH, Hegedüs L (28 March 2017). "Excess Mortality in Treated and Untreated Hyperthyroidism Is Related to Cumulative Periods of Low Serum TSH". The Journal of Clinical Endocrinology & Metabolism. 102 (7). The Endocrine Society: 2301–2309. doi:10.1210/jc.2017-00166. ISSN 0021-972X. PMID 28368540. S2CID 3806882.
  5. ^ Schraga ED (30 May 2014). "Hyperthyroidism, Thyroid Storm, and Graves Disease". Medscape. Archived from the original on 5 April 2015. Retrieved 20 April 2015.
  6. ^ NIDDK (13 March 2013). "Hypothyroidism". Archived from the original on 5 March 2016. Retrieved 20 April 2015.
  7. ^ Brent GA (June 2008). "Clinical practice. Graves' disease". The New England Journal of Medicine. 358 (24): 2594–2605. doi:10.1056/NEJMcp0801880. PMID 18550875.
  8. ^ Lee SY, Pearce EN (17 October 2023). "Hyperthyroidism: A Review". JAMA. 330 (15): 1472–1483. doi:10.1001/jama.2023.19052. PMC 10873132. PMID 37847271. S2CID 265937262.