Hyperthyroidism (Overactive Thyroid)

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What is hyperthyroidism (overactive thyroid)?

Hyperthyroidism, known as an overactive thyroid, is a medical condition in which your thyroid gland becomes excessively active and overproduces thyroid hormones. The thyroid gland is a butterfly-shaped organ located in the front of your neck, and it plays a crucial role in regulating your body's metabolism. Thyroid hormones can influence various bodily functions, including heart rate, energy production, and maintaining healthy skin, hair, and nails.

In cases of hyperthyroidism, your thyroid gland releases an excessive amount of thyroxine (T4) and triiodothyronine (T3), causing your body's metabolic rate to accelerate. This can lead to a range of symptoms, such as rapid heartbeat, weight loss, anxiety, and trembling hands. There are various underlying causes of hyperthyroidism, with Graves' disease, an autoimmune disorder, being a common one.

What causes hyperthyroidism (overactive thyroid)?

This condition is typically caused by one of the following factors:

  • Graves' Disease: Graves' disease is an autoimmune disorder in which your immune system mistakenly attacks the thyroid gland. This leads to an excessive production of thyroid hormones. It is the most common cause of hyperthyroidism.
  • Toxic multinodular goitre: in some cases, non-cancerous growths or nodules develop in the thyroid gland – a condition known as toxic multinodular goitre. When these nodules become overactive and produce thyroid hormones independently of the body's needs, hyperthyroidism can occur.
  • Thyroiditis: inflammation of the thyroid, known as thyroiditis, can cause a temporary release of excess thyroid hormones. This condition can be triggered by a viral infection or an autoimmune condition.
  • Excessive iodine: consuming too much iodine through diet or medication can lead to hyperthyroidism, especially if you have an underlying thyroid problem.
  • Tumours: in rare cases, benign or cancerous tumours in the ovaries or testes, known as ovarian or testicular choriocarcinomas, can produce hormones that stimulate the thyroid and cause hyperthyroidism.
hyperthyroidism symptoms
Hyperthyroidism leads to a range of symptoms, such as rapid heartbeat, weight loss, and anxiety.

What are the symptoms of hyperthyroidism (overactive thyroid)?

Symptoms of hyperthyroidism include: 

  • Unintentional weight loss
  • Nervousness and anxiety
  • Sweating and heat sensitivity
  • Increased heart rate
  • Tremors
  • Fatigue
  • Muscle weakness
  • Difficulty sleeping
  • Frequent bowel movements
  • Thinning hair
  • Exophthalmos
  • Menstrual changes
  • Breast enlargement

If you suspect you have symptoms of hyperthyroidism or are concerned about your thyroid health, consult with an endocrinologist for a proper evaluation and diagnosis.

Is hyperthyroidism (overactive thyroid) painful?

Hyperthyroidism itself is not typically painful, but it can lead to various uncomfortable symptoms that can cause discomfort and distress. For example, you might experience anxiety, nervousness, rapid heart rate, muscle weakness, and unintentional weight loss, all of which can be distressing. In some cases, complications of hyperthyroidism, such as heart problems or eye issues in Graves' disease, can be associated with discomfort or pain.

It is important to remember that while hyperthyroidism is not inherently painful, the symptoms it produces can significantly impact your overall well-being.

Who is at risk of hyperthyroidism (overactive thyroid) in Singapore?

The risk of hyperthyroidism (overactive thyroid) is influenced by various factors that can affect individuals in Singapore. Some factors that can increase your risk of developing hyperthyroidism include:

  • Gender: women are more commonly affected by hyperthyroidism than men. Although it can affect both genders, the risk is higher for women, especially in both the childbearing and menopausal years.
  • Age: the risk of hyperthyroidism tends to increase with age, particularly in people over 60.
  • Family history: if you have a family history of thyroid disorders, including hyperthyroidism, your risk may be elevated.
  • Autoimmune diseases: certain autoimmune disorders, such as Graves' disease, can increase the likelihood of hyperthyroidism.
  • Iodine intake: excessive iodine intake, often from dietary supplements or medications, can contribute to hyperthyroidism.
hyperthyroidism thyroid gland
Hyperthyroidism is often characterised by an abnormal thyroid gland.

How is hyperthyroidism (overactive thyroid) diagnosed?

Diagnosing hyperthyroidism involves a series of medical assessments and tests to evaluate thyroid function; these are:

  • Clinical assessment: to look for signs such as rapid heart rate, tremors, and eye changes, your rheumatologist will begin with a comprehensive evaluation of your medical history and a physical examination.
  • Blood tests: the primary diagnostic tool is a blood test that measures the levels of thyroid hormones, including thyroxine (T4) and triiodothyronine (T3), as well as thyroid-stimulating hormone (TSH). Elevated T3 and T4 levels with low TSH often indicate hyperthyroidism.
  • Radioactive iodine uptake (RAIU) test: an RAIU test measures how much radioactive iodine the thyroid absorbs. It can help differentiate between different causes of hyperthyroidism, such as Graves' disease or thyroid nodules.
  • Thyroid scan and/or ultrasound: a thyroid scan using radioactive iodine or technetium can provide a visual image of the thyroid gland, showing the size and location of nodules or areas of overactivity. A thyroid ultrasound can help identify the presence and characteristics of thyroid nodules or inflammation.
  • Fine-needle aspiration (FNA) biopsy: if a nodule is detected, an FNA biopsy (link to service page) may be performed to rule out thyroid cancer (link to service page). This involves the removal of a small tissue sample for examination.

Once diagnosed, your endocrinologist will work with you to determine the underlying cause of your hyperthyroidism and develop an appropriate treatment plan. Regular monitoring and follow-up are essential to ensure effective management of hyperthyroidism.

What are the treatment options for hyperthyroidism (overactive thyroid) in Singapore?

Treatment for hyperthyroidism is individualised according to condition severity and your overall health; hyperthyroidism can be treated in the following ways: 

  • Medications: methimazole or propylthiouracil can help reduce the production of thyroid hormones and alleviate symptoms.
  • Radioactive iodine therapy (RAI): RAI aims to reduce thyroid function and is a common treatment for Graves' disease.
  • Surgery: surgical removal of the thyroid gland or a partial thyroidectomy may be necessary for some cases of hyperthyroidism. Examples of thyroid surgery include transaxillary endoscopic thyroidectomy (link to service page), minimally invasive video-assisted thyroidectomy (MIVAT) (link to service page), conventional open hemithyroidectomy (link to service page), near-total thyroidectomy (link to service page), and total thyroidectomy +/- neck lymph node dissection (link to service page)
  • Beta-blockers: propranolol can be prescribed to manage symptoms such as rapid heart rate and tremors while the underlying cause of hyperthyroidism is addressed.

If you are suffering from a thyroid disorder, have a family history of thyroid disorders, or are concerned about developing thyroid cancer, schedule an appointment with ACE Surgery and Endoscopy for a detailed examination and individualised treatment plan. 

Frequently Asked Questions

Is hyperthyroidism curable?

Hyperthyroidism is typically managed rather than cured. The treatment aims to control symptoms and regulate thyroid hormone levels, but the underlying cause may influence the long-term prognosis.

Are there risks of recurrence with hyperthyroidism?

Yes, there can be a risk of recurrence in hyperthyroidism, especially if the underlying cause is not fully addressed.

Can hyperthyroidism lead to other health complications?

Yes, if left untreated or poorly managed, hyperthyroidism can lead to various health complications, such as heart issues, brittle bones, and eye problems. Seeking immediate treatment is important.

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Reyaz Moiz

Dr Reyaz Singaporewalla
Senior Consultant Endocrine and General Surgeon

MBBS (Bom), MS (Surg), DNB (Surg), FRCS (Edin), MMed (Singapore), FRCSEd.