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Overview

  • This Guidelines summary covers investigating all suspected thyroid disease and managing primary thyroid disease (related to the thyroid rather than the pituitary gland).

  • This summary does not include information on: 

    • managing thyroid cancer or thyroid disease in pregnancy
    • managing and monitoring subclinical hypothyroidism 
    • initial treatment in secondary/specialist care

NICE - thyroid disease algorithm

Hyperthyroidism in adults—management and monitoring. Download a PDF of this algorithm

Investigating suspected thyroid dysfunction or thyroid enlargement

Indications for tests for thyroid dysfunction

  • Consider tests for thyroid dysfunction for adults, children and young people if there is a clinical suspicion of thyroid disease, but bear in mind that 1 symptom alone may not be indicative of thyroid disease.
  • Offer tests for thyroid dysfunction to adults, children and young people with:
    • type 1 diabetes or other autoimmune diseases, or
    • new-onset atrial fibrillation
  • Consider tests for thyroid dysfunction for adults, children and young people with depression or unexplained anxiety
  • Consider tests for thyroid dysfunction for children and young people with abnormal growth, or unexplained change in behaviour or school performance
  • Be aware that in menopausal women symptoms of thyroid dysfunction may be mistaken for menopause
  • Do not test for thyroid dysfunction during an acute illness unless you suspect the acute illness is due to thyroid dysfunction, because the acute illness may affect the test results
  • Do not offer testing for thyroid dysfunction solely because an adult, child or young person has type 2 diabetes

Tests when thyroid dysfunction is suspected

  • Consider measuring thyroid-stimulating hormone (TSH) alone for adults when secondary thyroid dysfunction (pituitary disease) is not suspected. Then:
    • if the TSH is above the reference range, measure free thyroxine (FT4) in the same sample
    • if the TSH is below the reference range, measure FT4 and free tri-iodothyronine (FT3) in the same sample
  • Consider measuring both TSH and FT4 for:
    • adults when secondary thyroid dysfunction (pituitary disease) is suspected
    • children and young people

      If the TSH is below the reference range, measure FT3 in the same sample.
  • Consider repeating the tests for thyroid dysfunction in the full guideline if symptoms worsen or new symptoms develop (but no sooner than 6 weeks from the most recent test)

Managing primary hypothyroidism

Tests for people with confirmed primary hypothyroidism

Adults

  • Consider measuring thyroid peroxidase antibodies (TPOAbs) for adults with TSH levels above the reference range, but do not repeat TPOAbs testing

Children and young people

  • Measure TPOAbs for children and young people with TSH levels above the reference range, with possible repeat TPOAbs testing at the time of transition to adult services

Managing primary hypothyroidism

  • Offer levothyroxine as first-line treatment for adults, children and young people with primary hypothyroidism
  • Do not routinely offer liothyronine for primary hypothyroidism, either alone or in combination with levothyroxine, because there is not enough evidence that it offers benefits over levothyroxine monotherapy, and its long-term adverse effects are uncertain
  • Do not offer natural thyroid extract for primary hypothyroidism[1] because there is not enough evidence that it offers benefits over levothyroxine, and its long- term adverse effects are uncertain
  • Consider starting levothyroxine at a dosage of 1.6 mcg/kg of body weight per day (rounded to the nearest 25 mcg) for adults under 65 with primary hypothyroidism and no history of cardiovascular disease
  • Consider starting levothyroxine at a dosage of 25 to 50 mcg/day with titration for adults aged 65 and over and adults with a history of cardiovascular disease

Follow-up and monitoring of primary hypothyroidism

Tests for follow-up and monitoring of primary hypothyroidism

  • Aim to maintain TSH levels within the reference range when treating primary hypothyroidism with levothyroxine. If symptoms persist, consider adjusting the dose of levothyroxine further to achieve optimal wellbeing, but avoid using doses that cause TSH suppression or thyrotoxicosis.
  • Be aware that the TSH level can take up to 6 months to return to the reference range for people who had a very high TSH level before starting treatment with levothyroxine or a prolonged period of untreated hypothyroidism. Take this into account when adjusting the dose of levothyroxine.

Adults

  • For adults who are taking levothyroxine for primary hypothyroidism, consider measuring TSH every 3 months until the level has stabilised (2 similar measurements within the reference range 3 months apart), and then once a year
  • Consider measuring FT4 as well as TSH for adults who continue to have symptoms of hypothyroidism after starting levothyroxine

Children and young people aged 2 years and over

  • For children aged 2 years and over and young people taking levothyroxine for primary hypothyroidism, consider measuring FT4 and TSH:
    • every 6 to 12 weeks until the TSH level has stabilised (2 similar measurements within the reference range 3 months apart), then
    • every 4 to 6 months until after puberty, then
    • once a year

Children under 2 years

  • For children aged between 28 days and 2 years who are taking levothyroxine for primary hypothyroidism, consider measuring FT4 and TSH:
    • every 4 to 8 weeks until the TSH level has stabilised (2 similar measurements within the reference range 2 months apart), then
    • every 2 to 3 months during the first year of life, and
    • every 3 to 4 months during the second year of life

    For information on managing and monitoring subclinical hypothyroidism, see the full guideline.

Managing thyrotoxicosis

Tests for people with confirmed thyrotoxicosis

Adults

  • Differentiate between thyrotoxicosis with hyperthyroidism (for example, Graves’ disease or toxic nodular disease) and thyrotoxicosis without hyperthyroidism (for example, transient thyroiditis) in adults by:
    • measuring TSH receptor antibodies (TRAbs) to confirm Graves’ disease
    • considering technetium scanning of the thyroid gland if TRAbs are negative
  • Only consider ultrasound for adults with thyrotoxicosis if they have a palpable thyroid nodule

Children and young people

  • Differentiate between thyrotoxicosis with hyperthyroidism (Graves’ disease) and thyrotoxicosis without hyperthyroidism (for example, transient thyroiditis) in children and young people by:
    • measuring TPOAbs and TRAbs
    • considering technetium scanning of the thyroid gland if TRAbs are negative
  • Only offer ultrasound to children and young people with thyrotoxicosis if they have a palpable thyroid nodule or the cause of thyrotoxicosis remains unclear following thyroid autoantibody testing and technetium scanning

Initial treatment in primary/non-specialist care

  • Be aware that transient thyrotoxicosis without hyperthyroidism usually only needs supportive treatment (for example, beta-blockers)
  • Consider antithyroid drugs[2] along with supportive treatment for adults with hyperthyroidism who are waiting for specialist assessment and further treatment

For information on initial treatment in secondary/specialist care, see the full guideline.

Follow-up and monitoring of hyperthyroidism

Monitoring after radioactive iodine treatment

  • Consider measuring TSH, FT4 and FT3 levels in adults, children and young people every 6 weeks for the first 6 months after radioactive iodine treatment until TSH is within the reference range
  • For adults, children and young people who have hypothyroidism after radioactive iodine treatment and are not on antithyroid drugs, offer levothyroxine replacement therapy and follow recommendations made in Managing primary hypothyroidism on dosage of levothyroxine for adults and in Tests for follow-up and monitoring of primary hypothyroidism on monitoring of hypothyroidism
  • For adults, children and young people with TSH in the reference range 6 months after radioactive iodine treatment, consider measuring TSH (with cascading) at 9 months and 12 months after treatment
  • For adults, children and young people with TSH in the reference range 12 months after radioactive iodine treatment, consider measuring TSH (with cascading) every 6 months unless they develop hypothyroidism (then follow the recommendation above)
  • If hyperthyroidism persists after radioactive iodine treatment in adults, children and young people, consider antithyroid drugs[2] until the 6-month appointment
  • If hyperthyroidism persists 6 months after radioactive iodine treatment in adults, children and young people, consider further treatment

Monitoring after surgery

  • Offer levothyroxine to adults, children and young people after a total thyroidectomy and follow recommendations on dosage of levothyroxine for adults and on monitoring of hypothyroidism
  • Consider measuring TSH and FT4 at 2 and 6 months after surgery, and then TSH (with cascading) once a year for adults, children and young people who have had a hemithyroidectomy

Monitoring of antithyroid drugs

  • For adults, children and young people who are taking antithyroid drugs for hyperthyroidism, consider measuring:
    • TSH, FT4 and FT3 every 6 weeks until their TSH is within the reference range, then
    • TSH (with cascading) every 3 months until antithyroid drugs are stopped
  • Do not monitor full blood count and liver function for adults, children and young people taking antithyroid drugs for hyperthyroidism unless there is a clinical suspicion of agranulocytosis or liver dysfunction
  • For adults who have stopped antithyroid drugs, consider measuring:
    • TSH (with cascading) within 8 weeks of stopping the drug, then
    • TSH (with cascading) every 3 months for a year, then
    • TSH (with cascading) once a year
  • For children and young people who have stopped antithyroid drugs, consider measuring:
    • TSH, FT4 and FT3 within 8 weeks of stopping the drug, then
    • TSH, FT4 and FT3 every 3 months for the first year, then
    • TSH (with cascading) every 6 months for the second year, then
    • TSH (with cascading) once a year

Managing and monitoring subclinical hyperthyroidism

Treating subclinical hyperthyroidism

  • Consider seeking specialist advice on managing subclinical hyperthyroidism in adults if they have:
    • 2 TSH readings lower than 0.1 mIU/litre at least 3 months apart and
    • evidence of thyroid disease (for example, a goitre or positive thyroid antibodies) or symptoms of thyrotoxicosis
  • Consider seeking specialist advice on managing subclinical hyperthyroidism in all children and young people

Untreated subclinical hyperthyroidism

  • Consider measuring TSH every 6 months for adults with untreated subclinical hyperthyroidism. If the TSH level is outside the reference range, consider measuring FT4 and FT3 in the same sample
  • Consider measuring TSH, FT4 and FT3 every 3 months for children and young people with untreated subclinical hyperthyroidism
  • Consider stopping TSH measurement for adults, children and young people with untreated subclinical hyperthyroidism if the TSH level stabilises (2 similar measurements within the reference range 3 to 6 months apart)

For information on diagnosing, managing and monitoring thyroid enlargement with normal thyroid function, see the full guideline.

[1] Natural thyroid extract does not have a UK marketing authorisation so its safety is uncertain.

[2] Use of carbimazole is subject to MHRA advice on contraception (Drug Safety Update, February 2019) and risk of acute pancreatitis (Drug Safety Update, February 2019).

© NICE 2019. Thyroid disease: assessment and management. Available from: www.nice.org.uk/guidance/ng145. All rights reserved. Subject to Notice of rights.

NICE guidance is prepared for the National Health Service in England. All NICE guidance is subject to regular review and may be updated or withdrawn. NICE accepts no responsibility for the use of its content in this product/publication.

Published date: November 2019.