Do you often feel your heart racing, hands trembling, mood swings intensifying, and notice that your appetite increases while your weight keeps dropping? These may be typical signs of hyperthyroidism. In Hong Kong, hyperthyroidism is a common endocrine disorder, with a higher prevalence among women. This article will explain the causes of hyperthyroidism, outline its common symptoms, introduce the main treatment options, and address some of the most frequently asked questions from readers.
What Is Hyperthyroidism?
Hyperthyroidism (commonly referred to as “hyperthyroid”) is an endocrine disorder in which the thyroid gland produces excessive amounts of thyroid hormones (primarily T4 and T3) that enter the bloodstream, causing the body’s metabolism to accelerate abnormally. Thyroid hormones act like the body’s “accelerator pedal.” When levels are too high, all organs and systems shift into “high-speed mode,” leading to a series of symptoms associated with hypermetabolism.
What are the causes of hyperthyroidism?
There are many causes of hyperthyroidism, but common ones are related to autoimmune dysregulation.
- Graves’ Disease: The most common cause of hyperthyroidism. This is an autoimmune disorder in which the immune system mistakenly produces stimulating antibodies (TSH receptor antibodies, TRAb) that continuously trigger the thyroid gland to release hormones.
- Toxic Nodules (functional hyperactive thyroid nodules):
- Toxic single thyroid nodule: A single nodule in the thyroid independently secretes excessive thyroid hormones.
- Toxic multinodular goiter: Multiple nodules in the thyroid independently secrete excessive thyroid hormones.
- Thyroiditis: When the thyroid tissue becomes inflamed, stored thyroid hormones may be released in large amounts into the bloodstream, causing temporary hyperthyroid symptoms.
- Other factors:
- Genetic predisposition: Thyroid diseases often show familial clustering.
- Chronic stress: Long-term or severe psychological stress may affect the immune system and is considered a trigger for autoimmune hyperthyroidism such as Graves’ disease.
Classification of Hyperthyroidism
| Classification | Main Causes | Characteristics |
| Graves' Disease | Autoimmune reaction producing stimulatory antibodies (TRAb). | It usually leads to thyroid enlargement (goiter) and may be accompanied by thyroid eye disease (exophthalmos). |
| Functional hyperactive thyroid nodules | Single or multiple nodules within the thyroid secrete excessive hormones uncontrollably. | Commonly seen in older individuals and usually not associated with exophthalmos. |
| Thyroiditis | Inflammation of thyroid tissue leads to excessive hormone release. | The hyperthyroid phase is usually temporary and may later progress to normal thyroid function or hypothyroidism. |
High-Risk Groups for Hyperthyroidism
The high-risk groups for hyperthyroidism include:
- Gender: Women have a higher incidence rate than men.
- Genetic Factors: A family history of thyroid disease significantly increases the risk.
- History of Autoimmune Diseases: Individuals with other autoimmune conditions, such as type 1 diabetes, pernicious anemia, or rheumatoid arthritis.
- Age: More commonly seen in women aged 30 to 50, with an even higher likelihood in those over 60.
- Abnormal Iodine Intake: Both excessive and insufficient iodine intake in the diet may affect thyroid function.
Common Symptoms of Hyperthyroidism
Because thyroid hormones affect the body’s overall metabolism, the symptoms of hyperthyroidism are broad and complex in their presentation.
| System | Symptoms | Impact |
| Metabolism and Weight | Increased appetite but weight loss, excessive sweating, and heat intolerance. | Basal metabolic rate accelerated. |
| Cardiovascular System | Rapid heartbeat (palpitations), arrhythmias. | Long-term risk of heart failure may increase. |
| Nervous and Psychological System | Hand tremors, nervousness, anxiety, irritability, insomnia. | Over-excitation of the central nervous system. |
| Digestive System | Accelerated gastrointestinal motility, which may lead to diarrhea or increased frequency of bowel movements. | Increased appetite with frequent bowel movements |
| Muscles and Bones | Muscle weakness (especially in the upper arms and thighs), fatigue. | Long-term effects may include bone loss, increasing the risk of fractures. |
| Eyes | Exophthalmos (protruding eyes), photophobia, tearing, dryness, or eye pain. | Caused by immune reactions attacking the tissues around the eyes. |
| Appearance | Goiter (commonly referred to as “swollen neck”), thinning and easily breakable hair. | Enlargement of the thyroid gland. |
How Is Hyperthyroidism Diagnosed?
In Hong Kong, clinical practice generally involves thyroid blood tests (T3, T4, TSH), with ultrasound scans and autoantibody testing added when necessary to determine the cause and subtype.
- Blood Tests
- Thyroid Function Test: Measures the levels of T4, T3, and thyroid-stimulating hormone (TSH) in the blood. The typical pattern in hyperthyroidism is elevated T4 and T3, with suppressed TSH (as the pituitary gland attempts to reduce stimulation of the thyroid).
- Thyroid Antibody Test: Detects the presence of TRAb or other antibodies to confirm whether the condition is Graves’ disease.
- Thyroid Ultrasound: To evaluate the size, morphology, and blood flow of the thyroid gland, and to check for the presence of nodules or enlargement.
- Thyroid Nuclear Medicine Scan: The patient is given a small amount of radioactive iodine orally, and the uptake of iodine by the thyroid gland is observed.
There are three main approaches to treating hyperthyroidism. Doctors choose the most suitable method based on factors such as the underlying cause, the severity of the condition, and the patient’s age.
| Treatment Method | Mechanism | Indication |
| Drug Therapy | Taking antithyroid medications (such as Methimazole or Propylthiouracil) inhibits the synthesis and release of thyroid hormones. | The most common initial treatment, especially for patients with Graves’ disease. |
| Radioactive Iodine Therapy (RAI) | Taking a capsule or liquid containing radioactive iodine, which is absorbed by thyroid cells, the released radiation destroys the overactive thyroid cells. | Suitable for patients in whom drug therapy is ineffective, recurrent, or not suitable for surgery. Treatment may lead to hypothyroidism. |
| Surgery | Removal of part or all of the thyroid tissue (thyroidectomy). |
Suitable for patients with severe thyroid enlargement, compressive symptoms, coexisting malignant tumors, or those in whom drug or radioactive iodine therapy is ineffective. |
How to Prevent Hyperthyroidism?
Although most cases of hyperthyroidism are caused by autoimmune factors and are difficult to completely prevent, good health management can help reduce the risk and control the condition.
- Regular health check-ups: Pay attention to family history. High-risk groups should undergo regular thyroid function screening.
- Stress management: Chronic psychological stress is believed to trigger autoimmune diseases. Maintain relaxation, manage lifestyle and work stress, and keep emotions stable.
- Balanced diet: Ensure appropriate iodine intake. Avoid excessive consumption of seaweed and iodized salt, while maintaining a healthy diet and regular exercise.
Dietary Restrictions for Patients with Hyperthyroidism
Since iodine is the main raw material for producing thyroid hormones, patients with hyperthyroidism usually need to limit iodine intake, especially before receiving radioactive iodine therapy.
| Type | Food Examples | Recommendation |
| High-iodine foods | Seaweed (nori, kelp, kombu), seafood, sea salt. | Should be strictly limited or avoided, especially in patients with Graves’ disease or those preparing for radioactive iodine (RAI) therapy. |
| Stimulants | Strong tea, coffee, alcohol. | These may worsen symptoms such as palpitations, tremors, and anxiety, so intake should be reduced. |
| Other | Cruciferous vegetables (such as broccoli and cauliflower). | These vegetables may affect iodine absorption, but the effect is minimal. They do not need to be completely avoided; moderate consumption is sufficient. |
Frequently Asked Questions About Hyperthyroidism
Does Hyperthyroidism Cause “Eating More and Passing More”?
Yes. Because thyroid hormones accelerate metabolism and gastrointestinal motility, patients often experience increased appetite (“eating more”). At the same time, food passes through the intestines more quickly, leading to more frequent bowel movements or even diarrhea (“passing more”).
Does Hyperthyroidism Increase the Risk of Heart Failure and Bone Fractures?
Yes. Long-term hyperthyroidism keeps the heart in a state of chronic overload, raising the risk of arrhythmias and heart failure. At the same time, the high metabolic rate accelerates bone loss, which may lead to osteoporosis and increase the risk of fractures.
Why Do Patients with Hyperthyroidism Develop “Bulging Eyes”?
Bulging eyes (thyroid eye disease) almost always occur in patients with Graves’ disease. This happens because the immune system attacks the tissues and muscles around the eye socket, causing inflammation and swelling, which push the eyeballs forward.
Why Is Hyperthyroidism More Common in Women?
Hyperthyroidism (especially Graves’ disease) is an autoimmune disorder. The medical community generally believes that women’s immune systems are more complex than men’s and are more strongly influenced by hormonal fluctuations. As a result, women are more prone to autoimmune reactions, making hyperthyroidism more common among them.
If you suspect that you have symptoms of hyperthyroidism, it is recommended to promptly schedule an appointment with an endocrinologist or a family physician for diagnosis. Early detection and the development of a personalized treatment plan for hyperthyroidism are key to controlling the condition and preventing serious complications.
