Hyperthyroidism

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 ...