The thyroid is a butterfly-shaped gland, that sits at the base of the neck and one of its main functions is controlling metabolism
What is the Thyroid Gland?
The thyroid is a butterfly-shaped gland, that sits at the base of the neck, in front of the airpipe. One of its main functions is controlling metabolism1, 4
What are the main Thyroid Dysfunctions?
The main thyroid diseases that have been classified include:
Hypothyroidism – when the thyroid is underactive and not functioning adequately, leading to a decrease in hormone production, such as the thyroid hormone. This is the most common form of thyroid dysfunction2,2
Hyperthyroidism – when the thyroid is overactive and produces too much thyroid hormone3
Thyroid nodules – abnormal lumps/growths on the thyroid gland3
Thyroiditis – inflammation of the thyroid gland3
Over-medication with thyroid hormone3
What are the Causes of Hypothyroidism?
There are various causes of hypothyroidism (with subsequent decrease in thyroid hormone levels), including:
Iodine deficiency, as the thyroid gland needs iodine to produce its hormones, including thyroid hormone4
Auto-immune condition known as Hashimoto thyroiditis, where the body’s own defence system attacks the thyroid gland, damaging the gland, impacting its ability to function properly and produce thyroid hormone6, 7
Surgical removal of the thyroid gland
Radioiodine treatment of the thyroid gland (often used for treating hyperthyroidism of cancer of the thyroid gland)
Radiation therapy to the head or neck
Being born without a thyroid gland8
Disease to either the pituitary gland or hypothalamus in the brain, because the aforementioned organs stimulate the thyroid gland to function properly2
Postpartum thyroiditis – This is a condition that occurs in young mothers after giving birth and may include both hypothyroidism and hyperthyroidism. Postpartum thyroiditis can be a temporary condition or it can develop into long-term hypothyroidism6
What are the Signs and Symptoms of Hypothyroidism?
People with an underactive thyroid may experience the following:2,6
- Lack of energy
- Slow metabolism resulting in weight gain
- Lack of energy
- Thinning hair
- Increased sensitivity to cold
- Slow heart rate less than 60 beats per minute
- Impaired memory
- Pain, stiffness and swelling of muscles and joints
- Dry, puffy, pale skin
If you experience some of the above signs and symptoms, consult your doctor.
What are the Risk Factors for Hypothyroidism?
Although anyone can develop hypothyroidism, the following may increase your risk:3, 10
- Affects females more than males
- History of an autoimmune condition
- Family history of thyroid disease
- Received radiation (neck) or radioactive iodine therapy
- Thyroid surgery
How is Hypothyroidism Diagnosed?
- Diagnosing hypothyroidism is usually straightforward by means of a blood test, measuring the hormone thyrotropin (THS).
- TSH is produced by your pituitary gland to signal your thyroid gland to release more or less thyroid hormone.
- A TSH level within the normal range (0.4–2.5 mU/l) will exclude any significant malfunction of your thyroid gland.
- If the TSH level is just above the upper range of normal (above 2.5 mU/l), it is possible that you may develop hypothyroidism in the future.
- If the TSH level is elevated (above 4 mU/l), it is quite likely that you suffer from hypothyroidism, in which case more tests are now needed to confirm the diagnosis, assess the degree and determine the cause.3
How is Hypothyroidism Treated?
Hypothyroidism is treated by means of thyroid hormone replacement therapy, replacing what the body cannot produce on its own.11
- The thyroid pre-hormone levothyroxine is usually effective on its own in the treatment of hypothyroidism.11
- In rare occasions levothyroxine needs to be combined with triiodothyronine (T3) in order to achieve optimal metabolic control.6
What to Expect living with Hypothyroidism?
Depending on the cause, some cases would require thyroid hormone therapy for life (as with Hashimoto), yet other cases may only require short term thyroid hormone therapy (as with post-partum thyroiditis). Further:3, 6
- Your doctor will establish the correct dose of thyroid hormone for you
- Schedule regular check-ups with your doctor
- Be compliant to medication therapy
- With your hypothyroidism controlled, you will be able to live an entirely normal healthy life with a normal life span
A Word on Thyroid Function and Pregnancy
During pregnancy, the need for thyroid hormone will increase. Normally, a healthy thyroid gland will just simply respond to that need and produce more thyroid hormone from the amounts of iodine stored and supplied. However:9, 10
- If the capacity of your thyroid gland to produce adequate amounts of thyroid hormone is compromised, additional thyroid hormone must be supplied externally
- Pregnant women are at greater risk of developing hypothyroidism than the general population, as Oestrogens and other male and female hormones can affect the way your body handles thyroid hormones
- New mothers also have a greater chance of developing a thyroid disorder within the first months after delivery, partly because a deregulated immune system may cause postpartum thyroiditis
- Screening for thyroid disorders during early pregnancy and postpartum is therefore of utmost importance.10
What are the Causes of Hyperthyroidism?
Hyperthyroidism occurs for different reasons compared to hyperthyroidism:
The most common cause (up to 70% of all cases) is a disease of the immune system called Graves’ disease. Graves’ disease tends to run in families and occurs more frequently in young women.3
What are the Signs and Symptoms of Hyperthyroidism?
Symptoms usually vary, but may include:3
- Weight loss
- Excessive sweating
How is Hyperthyroidism Diagnosed?
Blood tests can confirm the diagnoses with ease and accuracy if it shows elevation in thyroid hormone T3 and/or T4.3
How is Hyperthyroidism Treated?
Treatment is aimed at reducing the over-production of thyroid hormones, and treatment options include the following:3
- Anti-thyroid medication
- Radioactive iodine treatment
- Surgical removal of the thyroid gland or nodule
A Word on Thyroid Nodules
Thyroid nodules can also cause hyperthyroidism.3 Nodules in the thyroid gland are very common, and approximately 5% of them are malignant (thyroid cancer).9, 10
- Therefore, nodules generally need further investigating by the doctor
- If the nodule is producing excessive amounts of thyroid hormone then the person will have symptoms of hyperthyroidism9,10
- Nobody is sure why people develop thyroid nodules, but a lack of dietary intake of iodine is thought to be a factor10
Please Note: This is an educational information leaflet only and should not be used for diagnosis. For more information on thyroid disorders, consult your healthcare professional.
From Causes of Thyroid Dysfunction material given in black in content:
1. American Thyroid Association. Thyroid Function Tests.
2005 http://www.thyroid.org/patients/brochures/FunctionTests_brochure.pdf. Accessed March 2009.
2. American Thyroid Association. ATA Hypothyroidism
Booklet. Falls Church, VA 2003.
3. American Thyroid Association. Hyperthyroidism. 2005
http://www.thyroid.org/patients/brochures/Hyper_brochure.pdf Accessed March 2009.
4. Roberts CG, Ladenson PW. Hypothyroidism. Lancet.
2004; 363: 793–803.
5. Families online. http://www.familiesonline.co.uk/article/articleview/114/1/12. Accessed March 2009.
6. American Association of Clinical Endocrinologists.
Hashimoto thyroiditis http://www.aace.com/pub/thyroidbrochures/pdfs/Hashimoto.pdf. Accessed March 2009.
7. American Thyroid Association. Hypothyroidism. 2005
http://www.thyroid.org/patients/brochures/Hypo_brochure.pdf Accessed March 2009.
8. Bettendorf M. Thyroid disorders in children from birth to adolescence. Eur J Nucl Med Mol Imaging. 2002; 29
Suppl 2: S439–46.
9. American Thyroid Association. Cancer of the thyroid.
http://www.thyroid.org/patients/brochures/ThyroidCancer_brochure.pdf Accessed March 2009.
10. American Thyroid Association. Thyroid nodules. 2005
http://www.thyroid.org/patients/brochures/Nodules_brochure.pdf Accessed March 2009.
References from Balancing Your Thyroid Gland Given in red in content
1. Khan A, Muzaffar M, Khan A et al. Thyroid Disorders, Etiology and
Prevalence. J Med Sci. 2002;2:89-94.
2. Canaris GJ, Manowitz NR, Mayor G et al. The Colorado thyroid disease
prevalence study. Arch Intern Med. 2000;160:526-34.
3. American Thyroid Association. ATA Hypothyroidism Booklet. Falls
Church, VA 2003
4. American Thyroid Association. Thyroid Function Tests. 2005 http://www.thyroid.org/patients/brochures/FunctionTests_brochure.pdf.
Accessed March 2009
5. American Thyroid Association. Hyperthyroidism. 2005
Accessed March 2009.
6. Ladenson PW; Lancet Vol. 363 No 9411, p 793-803
7. Bettendorf M. Thyroid disorders in children from birth to adolescence.
Eur J Nucl Med Mol Imaging. 2002; 29 Suppl 2: S439–46
8. WHO. Iodine defi ciency in 2007: Global progress since 2003
http://www.who.int/nutrition/publications/micronutrients/FNBvol29N3sep08.pdf. Accessed November 2011
9. De Groot LJ, Stagnaro-Green A, Vigersky R. Patient guide to the
management of maternal hyperthyroidism before, during and after
pregnancy. The Hormone Foundation. 2007
10. Fast Facts For Your Health. Thyroid Disease and Women. National
Women’s Health Resource Center. Red Bank, NJ.2006
11. SPC; packaging leaflet of Levothyroxine product