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Underactive and Overactive Thyroid - Hypo/Hyperthyroidism

What Is The Thyroid Gland? 

The thyroid gland is a butterfly-shaped gland found at the front of the neck attached to the trachea (windpipe). It secretes various hormones that regulate many metabolic activities in the body, which are involved in the process of turning food into energy. The two main hormones produced by the thyroid gland are triiodothyronine (T3) and thyroxine (T4); both of these need to be at the correct levels in order for your body to function normally, as they play a vital role in the body's metabolic rate, heart and digestive functions, muscle control, brain development and function, and the maintenance of bones. An imbalance of these hormones, either too low or too high, can lead to a variety of different symptoms throughout the body. The thyroid is regulated by Thyroid Stimulating Hormone (TSH) produced in the pituitary gland; when it detects an imbalance of thyroid hormones, it produces TSH as a response to get the body back to normal levels.

Image of someone holding a diagram of a thyroid gland in the palms of their hands

Hypothyroidism - Underactive Thyroid

What Is Hypothyroidism?

Hypothyroidism, also known as an underactive thyroid, is a condition caused when the levels of T3 and T4 are low due to the thyroid gland producing an insufficient amount. Whilst this can affect both men and women, it is more commonly seen in women. The main symptoms of an underactive thyroid are fatigue, weight gain and depression. These symptoms can be easily overlooked or mistaken for other conditions, resulting in people living with it for years without a proper diagnosis. The low levels of T3 and T4 mean the body can't process fats as usual, which can lead to raised cholesterol and narrowing of the arteries, which could result in heart problems such as angina or a heart attack. Once diagnosed, hypothyroidism can be easily treated with hormone tablets as a substitute.

What Causes Hypothyroidism? 

The most common causes of hypothyroidism are;

  • thyroiditis and inflammation of the thyroid gland that causes swelling and, in turn, decreases the amount of hormones produced.

  • iodine deficiency can also cause an underactive thyroid, as the thyroid gland uses iodine to produce thyroxine and triiodothyronine hormones.

How Is Hypothyroidism Diagnosed? 

The best way to diagnose an underactive thyroid is to run a thyroid function blood test; this test measures both the levels of thyroid stimulating hormone (TSH) as well as free T4 in the blood. Having high levels of TSH and low levels of T4 typically suggests that an underactive thyroid is responsible, whilst having high levels of TSH but normal T4 could indicate you're at risk of developing an underactive thyroid in the future. 

Hyperthyroidism - Overactive Thyroid

What Is Hyperthyroidism?

Hyperthyroidism, also known as an overactive thyroid, causes unusually high levels of thyroid hormones. Excess thyroid hormones speed up the body's metabolism, causing a range of symptoms, including anxiety, hyperactivity, unexplained weight loss, and swelling of the thyroid gland. 

Diagram displaying the difference between a healthy thyroid gland and an overactive thyroid gland

What Causes Hyperthyroidism? 

There are several factors that play a role in the development of Hyperthyroidism. Some of these include;

  • Genetics - passed down through family members, sometimes skipping a generation and landing on the next.

  • Graves' Disease - Graves' Disease is where the body's immune system mistakenly attacks the thyroid gland, meaning it goes on to overproduce too much of the thyroid hormone.

  • Thyroiditis - This may be caused by medications, viral infections, or conditions. Having thyroiditis will mean that the thyroid gland has become inflamed. 

How Is Hyperthyroidism Diagnosed?

Hyperthyroidism can be diagnosed through blood tests. By taking blood, we can measure the levels of your thyroid hormones, T3 and T4, as well as TSH. Once diagnosed with Hyperthyroidism, a treatment plan can be put in place by your medical professional and tailored to your needs.

Many patients who have had routine or in-depth Thyroid tests have found out they have underlying issues, sometimes without symptoms.

Feel free to call us or book a Private, NHS, or Children's blood test with us if you have any questions or are suspicious of symptoms. We can provide NHS blood tests with your form privately on behalf of GP’s or offer private blood tests through an external lab. We upload articles often, so be sure to look out for future blogs and follow us on social media for updates.

Please note, we are purely a Phlebotomy service, and all of our testing is sent off to an external private laboratory. We do not provide any diagnostics, testing, or screening services or offer any medical advice or interpretation of test results. These would need to be taken up with a Medical Practitioner.

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