History and exam

Key diagnostic factors

common

presence of risk factors

Key risk factors include female sex, middle age, family history of autoimmune thyroiditis, autoimmune disorders, treatment for thyroid disease, post-partum thyroiditis, Turner's and Down's syndromes, radiation therapy to head and neck, iodine deficiency, amiodarone use, and lithium use.

non-specific symptoms

Patients may have no symptoms or vague, non-specific symptoms (e.g., feeling slow) that are often clinically overlooked.[26]

Other diagnostic factors

common

lethargy

Is the predominant, but non-specific, symptom in people with hypothyroidism.[1][27] Other terms used are fatigue or tiredness.

constipation

Commonly reported.[1][27]

weight gain

Commonly reported.[1]

depression

Commonly reported. Depressive symptoms due to hypothyroidism usually respond to thyroid hormone replacement therapy; however, 5% to 10% of patients with well controlled levothyroxine-treated hypothyroidism have persistent symptoms.[1] 

menstrual irregularity

Commonly reported symptom.[1] Patients may also present with infertility.

dry or coarse skin

Reported by 63% of patients in one study.[27]

change in voice

A change in voice (hoarser, deeper) is commonly seen.[1][28]

bradycardia

Commonly reported.[1]

hypertension

Commonly reported.[1]

delayed relaxation of tendon reflexes

Commonly reported.[1]

uncommon

cold sensitivity

May be reported.[1][27]

coarse hair

May be noted.[28]

eyelid oedema

May be present.[28]

goitre

Goitre is generally uncommon. It is more common in areas of iodine deficiency and may also be present in autoimmune (Hashimoto) thyroiditis.[1][9][15]​​

Risk factors

strong

iodine deficiency

Iodine deficiency is a risk factor for hypothyroidism in the developing world and several high-income countries.[1][9] IGN: global scorecard of iodine nutrition 2021 Opens in new window​​​​ 

female sex

Autoimmune (Hashimoto's) thyroiditis, the most common cause of primary hypothyroidism in the US, is 8 to 9 times more common in women than men.[14]

middle age

Autoimmune thyroiditis has a peak incidence between age 30-50 years.[14]

family history of autoimmune thyroiditis

Autoimmune thyroiditis is more common in relatives of affected patients.[15]​ The genetics have autosomal dominance and polygenic features.[1][4]​​[15]

autoimmune disorders

Autoimmune thyroiditis is associated with other autoimmune disorders such as vitiligo or Sjogren's syndrome, and multiple endocrine deficiency, which can cause hypoparathyroidism, adrenal failure, ovarian failure, and type 1 diabetes mellitus.​​[15][23]

treatment for thyroid disease

Primary hypothyroidism may follow radioiodine ablation therapy or surgery for thyroid disease (e.g., Graves' disease, toxic nodular disease).[1]

post-partum thyroiditis

Has variable clinical course of hyperthyroidism or hypothyroidism usually followed by spontaneous resolution. Approximately 30% of women affected will remain hypothyroid one year post-partum.[18]

Turner's and Down's syndromes

Autoimmune thyroiditis is more common.[1][25]

radiotherapy to head and neck

The condition is common after radiotherapy for head and neck cancer.[1][15]

amiodarone use

About 14% of patients treated with amiodarone develop hypothyroidism.[1] Amiodarone contains a high iodine load, which can interfere with thyroid hormone synthesis.​[24]​​

lithium use

Lithium decreases thyroid hormone synthesis and blocks thyroid hormone release.[1][16]

weak

type 1 diabetes

About 10% of patients with type 1 diabetes mellitus develop thyroiditis, which may progress to hypothyroidism.[8]

infiltrative disease

Rarely, infiltrative diseases such as sarcoidosis and haemochromatosis can cause primary hypothyroidism.[1]

iodine excess

Autoimmune thyroiditis is more common in populations with high dietary iodine, which is thought to make the thyroid more antigenic.[21][22]

Use of this content is subject to our disclaimer