Primary hypothyroidism

Last reviewed: 2 Sep 2023
Last updated: 30 Mar 2023

Summary

Definition

History and exam

Key diagnostic factors

  • nonspecific symptoms
More key diagnostic factors

Other diagnostic factors

  • lethargy
  • constipation
  • weight gain
  • depression
  • menstrual irregularity
  • dry or coarse skin
  • change in voice
  • bradycardia
  • hypertension
  • delayed relaxation of tendon reflexes
  • cold sensitivity
  • coarse hair
  • eyelid edema
  • goiter
Other diagnostic factors

Risk factors

  • iodine deficiency
  • female sex
  • middle age
  • family history of autoimmune thyroiditis
  • autoimmune disorders
  • treatment for thyroid disease
  • postpartum thyroiditis
  • Turner and Down syndromes
  • type 1 diabetes
  • radiation therapy to head and neck
  • infiltrative disease
  • iodine excess
  • amiodarone use
  • lithium use
More risk factors

Diagnostic investigations

1st investigations to order

  • serum thyroid-stimulating hormone (TSH)
More 1st investigations to order

Investigations to consider

  • free serum thyroxine (T4)
  • antithyroid peroxidase antibodies
  • CBC
  • fasting blood glucose
  • serum cholesterol
More investigations to consider

Treatment algorithm

ONGOING

confirmed overt primary hypothyroidism

subclinical hypothyroidism with TSH >10 mIU/L

Contributors

Authors

Wail Malaty, MD

Adjunct Clinical Professor

Department of Family Medicine

University of North Carolina

Chapel Hill

NC

Disclosures

WM declares that he has no competing interests.

Peer reviewers

Sun Y. Lee, MD, MSc

Assistant Professor of Medicine

Boston University School of Medicine

Boston

MA

Disclosures

SYL declares that she has no competing interests.

Salman Razvi, MD, FRCP

Consultant Endocrinologist

Queen Elizabeth Hospital

Gateshead

UK

Disclosures

SR declares that he has no competing interests.

Lakdasa Premawardhana, MBBS, FRCP, FRCPE

Consultant Physician

Caerphilly Miners' Hospital

Caerphilly

UK

Disclosures

LP declares that he has no competing interests.

Birte Nygaard, MD, PhD

Associated Professor

Consultant Endocrinologist

Herlev Hospital

University of Copenhagen

Denmark

Disclosures

BN declares that she has no competing interests.

  • Differentials

    • Central or secondary hypothyroidism
    • Depression
    • Alzheimer dementia
    More Differentials
  • Guidelines

    • Thyroid disease in pregnancy
    • Asymptomatic thyroid dysfunction (2019)
    More Guidelines
  • Patient leaflets

    Underactive thyroid

    Underactive thyroid: questions to ask your doctor

    More Patient leaflets
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