What Is Hypothyroidism?

The most common cause of hypothyroidism worldwide is insufficient intake of iodine, a mineral found in iodized salt and some foods (such as seafood and dairy) that is needed for production of thyroid hormones. In the US and other high-income countries, the most common cause of hypothyroidism is an autoimmune condition called Hashimoto thyroiditis.1

Author/s:

Krista Roberts

Hyperthyroidism: A Review

Rowan Hutchins — Tue, 31 Oct 2023 05:00:00 +0000

Date Added:

October 31, 2023

Journal/Publication:

JAMA

Publisher:

AMA

Publication Date:

October 17, 2023

Issue:

Volume:

330

Pages:

1472–1483

URL:

Hyperthyroidism: A Review

Type:

Meta-analyses, Reviews, and Guidelines

DOI (1):

10.1001/jama.2023.19052

Keywords

PMID (1):

37847271

MeSH

Hyperthyroidism* / diagnosis

Thyroid Neoplasms / complications

Thyroxine / therapeutic use

Thyrotoxicosis / diagnosis

Graves Disease / diagnosis

Iodine / therapeutic use

A review of current evidence and recommendations regarding the evaluation and treatment of hyperthyroidism. James W. Mold, MD, MPH

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Importance: Overt hyperthyroidism, defined as suppressed thyrotropin (previously thyroid-stimulating hormone) and high concentration of triiodothyronine (T3) and/or free thyroxine (FT4), affects approximately 0.2% to 1.4% of people worldwide. Subclinical hyperthyroidism, defined as low concentrations of thyrotropin and normal concentrations of T3 and FT4, affects approximately 0.7% to 1.4% of people worldwide. Untreated hyperthyroidism can cause cardiac arrhythmias, heart failure, osteoporosis, and adverse pregnancy outcomes. It may lead to unintentional weight loss and is associated with increased mortality.

Observations: The most common cause of hyperthyroidism is Graves disease, with a global prevalence of 2% in women and 0.5% in men. Other causes of hyperthyroidism and thyrotoxicosis include toxic nodules and the thyrotoxic phase of thyroiditis. Common symptoms of thyrotoxicosis include anxiety, insomnia, palpitations, unintentional weight loss, diarrhea, and heat intolerance. Patients with Graves disease may have a diffusely enlarged thyroid gland, stare, or exophthalmos on examination. Patients with toxic nodules (ie, in which thyroid nodules develop autonomous function) may have symptoms from local compression of structures in the neck by the thyroid gland, such as dysphagia, orthopnea, or voice changes. Etiology can typically be established based on clinical presentation, thyroid function tests, and thyrotropin-receptor antibody status. Thyroid scintigraphy is recommended if thyroid nodules are present or the etiology is unclear. Thyrotoxicosis from thyroiditis may be observed if symptomatic or treated with supportive care. Treatment options for overt hyperthyroidism from autonomous thyroid nodules or Graves disease include antithyroid drugs, radioactive iodine ablation, and surgery. Treatment for subclinical hyperthyroidism is recommended for patients at highest risk of osteoporosis and cardiovascular disease, such as those older than 65 years or with persistent serum thyrotropin level less than 0.1 mIU/L.

Conclusions and Relevance: Hyperthyroidism affects 2.5% of adults worldwide and is associated with osteoporosis, heart disease, and increased mortality. First-line treatments are antithyroid drugs, thyroid surgery, and radioactive iodine treatment. Treatment choices should be individualized and patient centered.

Author/s:

Sun Y. Lee, Elizabeth N. Pearce