The term euthyroidism is used to describe a state in which thyroid gland is functioning normally. It indicates that blood TSH and T4 levels are normal. For people who have been diagnosed with hyperthyroidism or hypothyroidism, the goal of treatment is to return to a euthyroid state.1,2
This means taking your thyroid medications on time and in the right dose prescribed by your doctor. If you continue to experience symptoms despite taking your medication, inform your doctor so that they can assess your condition and adjust your treatment plan accordingly.
Once euthyroidism is achieved, lifelong annual thyroid function testing is recommended.
A euthyroid goitre is a condition in which the thyroid gland becomes enlarged but is functioning normally. The thyroid hormone levels are normal, and the person does not have hyperthyroidism or hypothyroidism.
Patients with an asymptomatic euthyroidgoitre can usually be observed without specific treatment. However, if the goitre is growing rapidly and causing difficulties in breathing or swallowing, your doctor may recommend surgery to remove the enlarged thyroid gland.3
Radioiodine therapy may be used to reduce the size of the goitre, and in some cases, serve as an alternative to surgery.4
Euthyroid sick syndrome (ESS) refers to changes in thyroid function tests due to severe illness or stress. It is also known as “non-thyroidal illness syndrome” because the alterations in thyroid hormones is not caused by a thyroid disorder.
This condition is seen in up to 75% of hospitalised patients. Causes of ESS vary widely and may include:5
ESS has also been reported in patients with COVID-19 infection.
To diagnose ESS, thyroid function tests for T3, T4 and TSH are needed. The most consistent hormone abnormality in ESS is a low T3 level.
Thyroid hormone replacement therapy is generally not needed. After the initial problem that caused ESS is treated, thyroid tests are expected to become normal again without further issues.5
Thyroid function abnormalities may persist for several weeks after discharge from hospital. Patients are advised to follow-up with the doctor to retest the thyroid levels after completely recovering from the illness.5
1. Ross DS, et al. 2016 American Thyroid Association guidelines for diagnosis and management of hyperthyroidism and other causes of thyrotoxicosis. Thyroid. 2016; 26: 1343-421.
2. Garber JR, et al. Clinical practice guidelines for hypothyroidism in adults: cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association. Endocr Pract. 2012; 18: 988-1028.
3. Hughes K, et al. Goitre –causes, investigation, treatment. Aust Fam Physician. 2012; 41: 572-6.
4. Führer D, et al. Euthyroid goiter with and without nodules – diagnosis and treatment. Dtsch Arztebl Int. 2012; 109: 506-15.
5. Ganesan K, et al. Euthyroid sick syndrome. Stat Pearls[Internet]. Last updated December 2022. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482219/. Accessed 17 May 2023.
