Hyperthyroidism

Hyperthyroidism, or overactive thyroid, is when the thyroid gland makes too much thyroid hormone.

The thyroid gland is a small, butterfly shaped gland located in the neck. It produces important hormones that help with metabolism, regulating body temperature, and other bodily functions.

Hyperthyroidism happens when the thyroid gland produces too much of its hormones. This overproduction of thyroid hormone speeds up the metabolism and bodily functions, causing weight loss, rapid heart rate, sweating, tremors, and anxiety.

Common causes of an overactive thyroid include Graves’ disease, thyroid nodules, and inflammation. Treatment options may include medications, surgery, and other therapies.

Learn more about hyperthyroidism, including its definition, causes, symptoms, diagnosis, treatment, and potential risks and complications.

What is hyperthyroidism?

Hyperthyroidism happens when the thyroid gland, located at the base of the neck, produces too much thyroid hormone (thyroxine, T4, and triiodothyronine, T3). These hormones regulate the body’s metabolism. Too much of these hormones can lead to a variety of symptoms and affect multiple organ systems.

How the thyroid works>>

Causes of hyperthyroidism

Hyperthyroidism can be caused by:

• Graves’ disease: The most common cause of hyperthyroidism, it is an autoimmune disorder where the immune system produces antibodies (thyroid-stimulating immunoglobulins) that stimulate the thyroid gland to produce excessive hormones.
• Toxic multinodular goiter: Multiple thyroid nodules within the thyroid gland produce excessive amounts of thyroid hormones.
• Toxic adenoma: A single thyroid nodule within the thyroid gland that autonomously produces excessive thyroid hormone.
• Subacute thyroiditis: Inflammation of the thyroid gland, often following a viral infection, leading to the release of stored thyroid hormones.
• Silent thyroiditis: A painless, often autoimmune-related inflammation of the thyroid.
• Postpartum thyroiditis: Inflammation of the thyroid gland occurring after childbirth.
• Iodine-induced hyperthyroidism: Excessive iodine intake from diet, medications, or supplements can lead to overproduction of thyroid hormones in susceptible individuals.

Symptoms of hyperthyroidism

Thyroid hormones are responsible for several important roles throughout the body. Hyperthyroidism can cause symptoms that affect multiple parts of the body and different systems. This can make it difficult to diagnose hyperthyroidism. Symptoms may include:

• Weight loss: Unintentional weight loss despite an increased appetite.
• Rapid heartbeat (tachycardia): Fast or irregular heartbeat.
• Nervousness and anxiety: Increased feelings of nervousness, anxiety, and irritability.
• Tremors: Shaking or trembling hands and fingers.
• Excessive sweating: Increased sweating and intolerance to heat.
• Increased appetite: Feeling hungry more often and eating more than usual.
• Hyperactivity: Increased energy and restlessness.
• Fatigue: Feeling tired and weak despite increased energy levels.
• Difficulty sleeping: Insomnia or restlessness at night.
• Frequent bowel movements: Increased frequency of bowel movements or diarrhea.
• Menstrual changes: Irregular or lighter menstrual periods in women.
• Goiter: Enlarged thyroid gland, visible as swelling at the base of the neck.
• Hair and skin changes: Fine, brittle hair and thinning skin.

Symptoms specific to Graves’ disease

• Graves’ ophthalmopathy: Eye symptoms including bulging eyes (exophthalmos), redness, swelling, and double vision.
• Graves’ dermopathy: Thickened, red skin usually on the shins or tops of the feet.

Diagnosis of hyperthyroidism

Medical history and physical examination

• Symptom assessment: Detailed inquiry about symptoms such as weight loss, rapid heartbeat, nervousness, and heat intolerance.
• Medical history: Review of risk factors, including family history of thyroid disease, recent pregnancies, and use of medications affecting thyroid function.
• Physical examination: Examination of the neck to palpate the thyroid gland, assess its size, consistency, and presence of nodules, and evaluate signs of hyperthyroidism.

Diagnostic tests

If your health care provider suspects you may have hyperthyroidism, they may use tests to help diagnose the condition, including:

• Blood tests:
  • Thyroid-stimulating hormone (TSH): Typically low in hyperthyroidism.
  • Free thyroxine (T4) and triiodothyronine (T3): Elevated levels confirm hyperthyroidism.
  • Thyroid antibodies: Testing for thyroid-stimulating immunoglobulins (TSI) and thyroid peroxidase antibodies (TPO) to diagnose autoimmune causes like Graves’ disease.
• Radioactive iodine uptake (RAIU) test: Measures how much radioactive iodine the thyroid gland absorbs from the bloodstream, helping to differentiate between different causes of hyperthyroidism.
• Thyroid scan: Imaging using a small amount of radioactive material to visualize the thyroid gland and assess the distribution of iodine uptake.
• Thyroid ultrasound: Imaging to evaluate the size, structure, and presence of nodules in the thyroid gland.

Treatment of hyperthyroidism

Treatment for hyperthyroidism can depend on the cause of the condition. Treatment options may include:

Medical treatments

• Antithyroid medications:
  • Methimazole: Inhibits thyroid hormone production.
  • Propylthiouracil (PTU): Inhibits thyroid hormone production and conversion of T4 to T3. Often used during pregnancy as it is preferred in the first trimester.
• Beta-blockers: Medications like propranolol to manage symptoms such as rapid heartbeat, tremors, and anxiety by blocking the effects of thyroid hormones on the body.

Radioactive iodine therapy

Radioactive iodine therapy: Administering radioactive iodine orally to destroy overactive thyroid cells, reducing hormone production. It is a common treatment for Graves’ disease, toxic multinodular goiter, and toxic adenoma.

Surgical treatments

Thyroidectomy: Surgical removal of part (partial thyroidectomy) or all (total thyroidectomy) of the thyroid gland, typically indicated for patients who cannot tolerate antithyroid medications or radioactive iodine therapy, or have large goiters causing compressive symptoms, or suspicion of thyroid cancer.

Potential risks and complications

Complications of untreated hyperthyroidism

• Thyroid storm: A rare, life-threatening condition characterized by a sudden and severe exacerbation of hyperthyroidism symptoms, including high fever, rapid heartbeat, and delirium.
• Heart problems: Increased risk of heart arrhythmias such as atrial fibrillation, heart failure, and other cardiovascular issues.
• Osteoporosis: Increased bone loss leading to weakened bones.
• Eye complications: Particularly in Graves’ disease, untreated hyperthyroidism can lead to severe eye problems and vision loss.

Long-term considerations

• Ongoing monitoring: Regular follow-up with blood tests to monitor thyroid function and ensure appropriate management of thyroid hormone levels.
• Thyroid hormone management: Lifelong thyroid hormone replacement therapy may be necessary if hypothyroidism develops after treatment.
• Eye care: Ongoing management of eye symptoms in patients with Graves’ ophthalmopathy, including possible referral to an ophthalmologist.

Impact on quality of life

• Symptom relief: Effective treatment can alleviate symptoms, improve thyroid function, and enhance overall well-being.
• Informed decision-making: Accurate diagnosis aids in making informed decisions about treatment and preventive measures.
• Emotional support: Providing counseling and support to address anxiety, depression, and the psychological impact of living with hyperthyroidism or undergoing treatment.

Hyperthyroidism is a common condition that can significantly impact multiple organ systems if left untreated. Early diagnosis and appropriate intervention are crucial for managing symptoms and preventing complications. Understanding the causes, symptoms, diagnostic methods, and treatment options is essential for effective management. If you or a loved one are experiencing symptoms or have risk factors for hyperthyroidism, consulting with a health care provider, endocrinologist, or specialized surgeon will help determine the need for further evaluation and develop a suitable treatment plan tailored to your specific needs and circumstances.