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Underactive thyroid (hypothyroidism)

Hypothyroidism, also known as underactive thyroid, is a fairly common condition where your thyroid gland does not produce enough thyroid hormone. 

A man having his thyroid examined by a doctor

The thyroid gland is located in the lower front part of your neck, and the hormones it releases are vital to almost all parts of the body and affect processes including metabolism, heart beat and temperature regulations. 

Hypothyroidism upsets the normal chemical reactions in your body, and if left untreated can cause a host of problems, including obesity, joint pain, infertility, heart failure, joint disease and death. 

The most common cause is Hashimoto’s thyroiditis, an autoimmune disease, but other causes include:

  • Radiation therapy to the neck area (used to treat certain cancers)
  • The use of certain medications
  • Too little iodine in the diet
  • Thyroid surgery to remove the thyroid
  • Undeveloped thyroid gland from birth
  • Pregnancy

Being female and over 60 years of age are risk factors.

What are its symptoms?

Symptoms of hypothyroidism may develop slowly over time, and include:

  • Dry hair and hair loss
  • Constipation
  • Feeling sluggish 
  • Fatigue
  • Menstrual cycle changes
  • Slower heart rate
  • Depression
  • Goitre (swelling of the thyroid gland)
  • Unexplained weight gain
  • Increased sensitivity to cold
  • Muscle aches

In newborn babies whose thyroid gland is not working properly, symptoms include jaundice, frequent choking, a large, protruding tongue, a puffy face, poor muscle tone and excessive sleeping. If untreated, babies are likely to have trouble feeding, and may fail to grow and develop normally. 

In children and teens, hypothyroidism will have the same symptoms as adults, but they may also experience poor growth (short stature), delayed dental development, delayed puberty and poor mental development. 

How is it diagnosed? 

If you present with symptoms, your doctor may order blood tests to check your hormone levels to confirm a diagnosis. These tests may include checking the levels of:

  • Thyroid-stimulating hormone
  • Thyroxine or T4

Further tests may include:

  • A thyroid ultrasound or throat scan to check for inflammation or nodules

What are your treatment options? 

Hypothyroidism treatment takes the form of a prescription synthetic thyroid hormone (T4) that will need to be taken daily. Thereafter, regular blood tests are recommended to make sure your levels remain constant. The importance of regular, daily medication for life will be emphasised by your doctor. 

Some over-the-counter medications and supplements may interfere with this medication, so inform your doctor about everything you’re taking.

Can it be prevented? 

Hypothyroidism can’t be prevented, so it’s important to watch for signs of the disorder, as well as being aware of risk factors which include:

If you are at risk of developing hypothyroidism, it is advisable to be screened from the age of 35 and every five years thereafter. 

IMAGE CREDIT: 123rf.com

The accuracy of this information was checked and approved by physician Dr Thomas Blake in June 2016