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Written by Kuek Yi Ling, pharmacist

What is hypothyroidism?

Hypothyroidism is a condition in which the thyroid gland is not able to produce enough thyroid hormone. The thyroid gland is a small butterfly-shaped gland in the neck, just in front of the windpipe (trachea).

One of its main functions is to produce hormones that help regulate the body’s metabolism. These hormones are called triiodothyronine (T3) and thyroxine (T4). Many of the body’s functions slow down when the thyroid does not produce enough of these hormones.

Hypothyroidism can affect any gender and occur at any age. There is no prevention for this disease.

Symptoms 

Commonly include, but are not limited to:

  • Feeling tired
  • Weight gain due to fluid retention and decreased metabolism
  • Dry and coarse skin, facial puffiness especially around the eyes
  • Sensitivity to cold
  • Slowed heart rate, movements and speech
  • Joint and muscle pain, cramps and weakness
  • Constipation
  • Thin,brittle hair or fingernails
  • Loss of libido
  • Depressed mood, forgetful
  • Loss of appetite
  • Irregular periods or heavy periods

Causes

  • Hashimoto’s thyroiditis (autoimmune)
  • Drugs eg. those used to treat overactivity of the thyroid gland, lithium and amiodarone
  • Previous surgical removal of the thyroid gland
  • Previous radioactive iodine therapy
  • Disorders of the hypothalamus or pituitary gland

Diagnosis

Thyroid gland may be enlarged.

Blood tests

  • Level of thyroid-stimulating hormone (TSH) – above normal (usually > 4.5mU/L) suggests a possible diagnosis of hypothyroidism
  • Level of free T4 hormone – should be measured to differentiate overt hypothyrodism (low free t4) from subclinical hypothyroidism (normal free T4)

Treatment

Treatment can eliminate or reduce the symptoms  of hypothyroidism. It has to be continued for life because treatment does not cure the disease.

  • Thyroid replacement hormone (L-thyroxine). Begins with a small dose and slowly increase about every 4 weeks
  • After 3 to 4 months , the level of TSH has to be measured periodically to determine the dose

 

Iodine and nutrition

Iodine is an essential mineral for maintaining the normal functions of thyroid gland. Iodine deficiency is one of the most common causes of goiter development, or abnormal enlargement of the thyroid gland. Maintaining adequate iodine intake is important for most people.

However, those with autoimmune thyroid disease can be particularly sensitive to the effects of iodine, meaning that it can trigger or worsen hypothyroidism. They should inform their doctor if they are sensitive to the effects of iodine.

People with hypothyroidism should discuss any major dietary changes with their doctor, especially when starting a high fiber diet, or eating lots of soy or cruciferous vegetables. Diet can affect the way in which the body absorbs thyroid medication.

References

  1. PORTAL MyHEALTH. 2012. Hypothyroidism – PORTAL Myhealth. [online] Available at: <http://www.myhealth.gov.my/en/hypothyroidism/>
  2. MSD Manual Professional Edition. 2019. Hypothyroidism – Endocrine And Metabolic Disorders – MSD Manual Professional Edition. [online] Available at: <https://www.merckmanuals.com/professional/endocrine-and-metabolic-disorders/thyroid-disorders/hypothyroidism >
  3. Specialty.mims.com. 2018. Hypothyroidism Diagnosis | MIMS Malaysia. [online] Available at: <https://specialty.mims.com/hypothyroidism/diagnosis?channel=endocrinology >
  4. Medicalnewstoday.com. 2018. Hypothyroidism: Causes, Symptoms, And Treatment. [online] Available at: <https://www.medicalnewstoday.com/articles/163729#symptoms >
  5. James Norman MD, n.d. Hypothyroidism: Overview, Causes, And Symptoms. [online] EndocrineWeb. Available at: <https://www.endocrineweb.com/conditions/thyroid/hypothyroidism-too-little-thyroid-hormon>
  6. Emedicine.medscape.com. n.d. Hypothyroidism Treatment & Management: Approach Considerations, Hypothyroidism In Pregnancy, Subclinical Hypothyroidism. [online] Available at: <https://emedicine.medscape.com/article/122393-treatment >
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