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For further information, see CMDT Part 26-09: Hyperthyroidism (Thyrotoxicosis)

Key Features

Essentials of Diagnosis

  • Sweating, weight loss or gain, anxiety, palpitations, loose stools, heat intolerance, menstrual irregularity

  • Tachycardia; warm, moist skin; stare; tremor

  • Graves disease

    • Most common cause of hyperthyroidism

    • Most patients have a palpable goiter (sometimes with bruit); ophthalmopathy

  • Amiodarone: most common cause of thyrotoxic crisis "thyroid storm"

  • Suppressed TSH in primary hyperthyroidism; usually increased T4, FT4, T3, FT3

General Considerations

Graves disease

  • Most common cause of thyrotoxicosis

  • An autoimmune disorder, characterized by an increase in synthesis and release of thyroid hormones

  • More common in women than in men (8:1)

  • Onset usually between the ages of 20 and 40 years

  • May be accompanied by infiltrative ophthalmopathy (Graves exophthalmos) and, less commonly, by infiltrative dermopathy (pretibial myxedema)

  • Patients with Graves disease have an increased risk of other systemic autoimmune disorders, including

    • Sjögren syndrome

    • Celiac disease

    • Pernicious anemia

    • Addison disease

    • Alopecia areata

    • Vitiligo

    • Type 1 diabetes mellitus

    • Hypoparathyroidism

    • Myasthenia gravis

    • Cardiomyopathy

Toxic multinodular goiter and thyroid nodules

  • Autonomous hyperfunctioning thyroid nodules that produce hyperthyroidism are known as toxic multinodular goiter (Plummer disease); a single hyperfunctioning nodule can also produce hyperthyroidism

  • More prevalent among older adults and in iodine-deficient regions

  • Toxic multinodular goiter and Graves disease may sometimes coexist in the same gland (Marine-Lenhart syndrome)

  • Thyroid cancer is found in about 4.7% of patients with toxic multinodular goiter

Autoimmune thyroiditis

  • These conditions cause thyroid inflammation with release of stored hormone

  • Painless (silent) subacute thyroiditis

    • Also known as subacute lymphocytic thyroiditis or "hashitoxicosis"

    • Can occur spontaneously

    • Women are affected four times more frequently than men

    • Can also be caused by some medications including

      • Chemotherapeutic agents (such as tyrosine kinase inhibitors [eg, axitinib, sorafenib, sunitinib]; denileukin diftitox; alemtuzumab; interferon-alpha; interleukin-2; and immune checkpoint inhibitors)

      • Lithium

      • Amiodarone

  • Postpartum thyroiditis

    • Occurs in the first 12 months postpartum and occasionally after miscarriages

    • See Thyroiditis

  • Painful subacute thyroiditis

    • Also known as "de Quervain" or "granulomatous" thyroiditis

    • Typically caused by various viral infections

    • Women are affected four times more frequently than men

    • See Thyroiditis

Amiodarone-induced hyperthyroidism

  • The leading cause for thyrotoxic crisis ("thyroid storm")

  • Causes thyrotoxicosis in about 3% of patients in the United States

  • Induces thyrotoxicosis in about 20% of patients in Europe and iodine-deficient geographic areas

  • Thyrotoxicosis can occur suddenly at any time during treatment and may even develop several months after it has been discontinued

Clinical Findings

Symptoms and Signs

  • Heat intolerance, sweating

  • Palpitations

  • Pruritus

  • Frequent bowel movements

  • Weight loss (or gain)

  • Menstrual irregularities

  • Nervousness, fine resting tremor

  • Fatigue

  • Muscle weakness, muscle cramps, hyperreflexia

  • Tetany (rare)

  • Thyroid

    • Goiter (often with a bruit) in ...

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