Hyperthyroidism is a condition caused by an overactive thyroid gland, leading to excessive production of the thyroid hormone thyroxine (T4). This excess hormone accelerates the body’s natural metabolism and may result in weight loss, increased energy levels, and a rapid or irregular heartbeat. Hyperthyroidism occurs more commonly in women than in men.
The thyroid gland, located at the front of the neck, plays a vital role in regulating many body functions. It helps control how the body uses fats and carbohydrates, body temperature, heart rate, protein production, and calcium levels in the blood.
Some symptoms of hyperthyroidism—such as weight loss or increased energy—may initially be perceived as positive, which can delay diagnosis. However, if left untreated, hyperthyroidism can lead to serious health complications. Although it is often a lifelong condition, most people respond well to treatment.
What causes hyperthyroidism?
The most common causes of hyperthyroidism include:
- Graves’ disease – an autoimmune condition in which the immune system stimulates the thyroid to produce excessive hormone
- Plummer disease (toxic multinodular goitre)
- Overactive thyroid nodules, which independently produce thyroid hormone
- Thyroiditis, where inflammation of the thyroid causes hormone leakage; this may occur due to viral or bacterial infections, pregnancy, or autoimmune disease
- Excessive iodine intake from food, supplements or medications
- Over-replacement with thyroid hormone medication used to treat hypothyroidism
Who is most at risk of hyperthyroidism?
- People at increased risk include:
- Women aged 20–30 years and older women
- Pregnant women
- Individuals with a family history of autoimmune or thyroid disorders, particularly Graves’ disease
- People with chronic autoimmune conditions such as type 1 diabetes, pernicious anaemia, or primary adrenal insufficiency
What are the symptoms of hyperthyroidism?
Hyperthyroidism can cause a wide range of symptoms, which may vary in severity:
- Unintentional weight loss despite normal or increased appetite
- Rapid heart rate (tachycardia)
- Irregular heartbeat (arrhythmia)
- Palpitations
- Increased appetite
- Anxiety, nervousness and irritability
- Tremors in the hands or fingers
- Excessive sweating
- Increased sensitivity to heat
- Changes in bowel habits
- Changes in menstrual patterns
- Goitre (enlarged thyroid) at the base of the neck
- Fatigue and muscle weakness
- Difficulty sleeping (insomnia)
- Thinning of the skin
- Fine, brittle hair
What are the complications of hyperthyroidism if left untreated?
If left untreated, hyperthyroidism may lead to:
- Heart complications, including rapid heart rate and rhythm disturbances, increasing the risk of heart failure or stroke
- Osteoporosis due to accelerated bone loss
- Eye problems, particularly in Graves’ disease (Graves’ ophthalmopathy), which may cause bulging, red or swollen eyes, light sensitivity, blurred or double vision, and in severe cases, vision loss
- Thyrotoxic crisis (thyroid storm), a life-threatening condition characterised by fever, rapid pulse and confusion or delirium, requiring immediate medical attention
How is hyperthyroidism diagnosed?
Dr Imran will begin with a thorough medical history and physical examination. During the
examination, he will assess for signs such as:
- Fine tremors in the fingers
- Overactive reflexes
- Eye changes
- Warm, moist skin
- Elevated pulse rate
- Thyroid enlargement while swallowing
Blood tests will be arranged to measure thyroid hormone levels. Depending on the results,
further investigations may include:
- Radioiodine uptake test
- Thyroid scan
- Thyroid ultrasound
Can hyperthyroidism be prevented?
In most cases, hyperthyroidism cannot be prevented, as it is commonly related to genetic or autoimmune factors or hormonal changes during pregnancy.
Treatment and management of hyperthyroidism
Treatment depends on factors such as age, overall health, cause and severity of the condition.
Options may include:
- Radioactive iodine therapy (taken orally)
- Anti-thyroid medications, such as methimazole or propylthiouracil
- Beta blockers to control symptoms such as rapid heart rate and tremor
- Surgery to remove part or all of the thyroid gland
Dr Imran will discuss the most appropriate treatment options with you, taking into account your individual circumstances and preferences.
To arrange a consultation, please ask your GP for a referral and contact us on T: 07 3050 4907.