Thyroid disorders

Last updated: June 27, 2026

CME information and disclosures

This article is part of an accredited activity. For full CME information and disclosures, please click on the link in this reference: ^[1]

Summary

This article provides an overview of the most common thyroid disorders (hypothyroidism and hyperthyroidism) and thyroid function testing.

For more information on specific conditions, see the articles on “Hypothyroidism,” "Hyperthyroidism and thyrotoxicosis,” “Thyroid nodules,” and “Thyroid cancer.”

Overview of thyroid-related disorders

Overview of clinical features in thyroid-related disorders
	Hypothyroidism	Hyperthyroidism
Ocular	Periorbital edema	Lid lag Lid retraction (“staring look”) Graves ophthalmopathy (exophthalmos, periorbital edema)
Vocal	Hoarse voice, difficulty articulating words	Tremulous voice
Dermatological	Cold, dry skin Decreased sweating Puffy appearance Pretibial edema Coarse hair Hair loss Brittle nails	Warm, moist skin Excessive sweating Infiltrative dermopathy, especially in the pretibial area (pretibial myxedema) Fine hair Diffuse hair loss Onycholysis
Thyroid	Goiter (in Hashimoto thyroiditis) Atrophic thyroid (in atrophic thyroiditis)	Diffuse, smooth, nontender goiter, often with audible bruit (in Graves disease)
Metabolic	Cold intolerance Fatigue, decreased physical activity Weight gain (despite decreased appetite)	Heat intolerance Weakness, fatigue Weight loss (despite increased appetite)
Cardiovascular	Bradycardia Myxedematous heart disease (dilated cardiomyopathy, bradycardia, dyspnea) Decreased cardiac output	Tachycardia Palpitations, irregular pulse Hypertension with widened pulse pressure Increased systolic pressure Decreased diastolic pressure Abnormal heart rhythms (e.g., atrial fibrillation) Chest pain
Musculoskeletal	Hypothyroid myopathy (proximal muscle weakness with elevated creatine kinase levels) Entrapment syndromes (e.g., carpal tunnel syndrome) Myoedema	Hyperthyroid myopathy (proximal muscle weakness with normal creatinine kinase levels) Osteopathy (osteoporosis)
Gastrointestinal	Constipation	Frequent bowel movements (due to intestinal hypermotility)
Reproductive	Abnormal menstrual cycle (secondary amenorrhea or menorrhagia) Galactorrhea Decreased libido, erectile dysfunction, delayed ejaculation, and infertility in men	♀: oligo/amenorrhoea, anovulatory infertility, dysfunctional uterine bleeding ♂: gynecomastia, decreased libido, infertility, erectile dysfunction
Neuropsychiatric	Impaired cognition (concentration, memory) Somnolence Depression Hyporeflexia Woltman sign	Anxiety Restlessness Insomnia Tremulousness (e.g., fine tremor in outstretched fingers) Hyperreflexia

For further information, see “Hypothyroidism” and "Hyperthyroidism and thyrotoxicosis.”

Hypothyroidism and hyperthyroidism fact sheet Graves ophthalmopathy Patient with goiter

Thyroid function tests

Overview of thyroid function tests in thyroid disorders
‎		Etiology	Thyroid function tests
‎		Etiology	TSH level	Free T₄	Free T₃
Overt hypothyroidism	Primary hypothyroidism	Hashimoto thyroiditis (most common cause) Iatrogenic (e.g., following thyroidectomy or radioiodine therapy) Antithyroid medication (e.g., amiodarone, lithium) Transient hypothyroidism (e.g., silent thyroiditis, subacute granulomatous thyroiditis, postpartum thyroiditis)	↑	↓
	Secondary hypothyroidism	Pituitary disorders (e.g., pituitary adenoma) Infiltrative diseases Iatrogenic (e.g., following pituitary surgery)	↓
	Tertiary hypothyroidism	Hypothalamic disorders	↓
Subclinical hypothyroidism		Asymptomatic Same etiology as primary hypothyroidism	Mildly ↑	Normal
Euthyroid sick syndrome	Low T₃ syndrome	Occurs in severe illness or severe physical stress (most common in intensive care patients)	Normal	Normal	↓
Euthyroid sick syndrome	Low T₃ low T₄ syndrome		Normal	↓	↓
Primary hyperthyroidism		Graves disease Toxic MNG Toxic adenoma (see “Thyroid nodules” and “Thyroid cancer”) Postpartum thyroiditis Subacute granulomatous thyroiditis (de Quervain thyroiditis)	↓	↑
Secondary hyperthyroidism		Thyrotropic adenoma	Normal/↑	↑
Subclinical hyperthyroidism		Same etiology as primary hyperthyroidism	↓	Normal

For further information, see “Diagnostics” in “Hypothyroidism” and “Overview” in "Hyperthyroidism and thyrotoxicosis.”

Start your trial, and get 5 days of unlimited access to over 1,100 medical articles and 5,000 USMLE and NBME exam-style questions.

Start free trial

Evidence-based content, created and peer-reviewed by physicians. Read the disclaimer