Hyperthyroidism: Symptoms, Treatment, and Metabolism – When the Thyroid Gland Produces Too Many Hormones

The thyroid gland is a vital organ that regulates metabolism. Normally, the production of thyroid hormones is strictly regulated by the pituitary gland via the hormone TSH. In cases of hyperthyroidism, this regulatory loop is often inhibited or disrupted. The excess hormones constantly stimulate the cells to work, which increases oxygen demand and heat production. When the thyroid gland produces too many hormones, the body’s internal balance is disrupted, affecting nearly every other organ.

An overactive thyroid leads to an accelerated metabolism. 

This manifests as:

• a faster heart rate
• sleep problems, as well as 
• inner restlessness

However, with appropriate treatment, those affected can certainly lead a normal life.

The prevalence of hyperthyroidism varies by age. It is rare in children but becomes more common with increasing age. Hyperthyroidism is the second most common thyroid disorder.

When symptoms do occur, they are often very pronounced. Common symptoms include a persistently elevated heart rate, trembling hands, and a marked intolerance to heat accompanied by excessive sweating. Many people with hyperthyroidism also complain of sleep disturbances, irritability, and muscle weakness. Another typical symptom is weight loss despite intense hunger. In the form known as Graves’ disease, protruding eyes (endocrine orbitopathy) may also occur as a specific sign of hyperthyroidism or hypothyroidism.

Hyperthyroidism can result from various causes. However, in approximately 95 percent of all patients, Graves’ disease or thyroid autonomy is responsible for the onset of hyperthyroidism.

Graves’ disease is also known as Basedow’s disease and is classified as an autoimmune disorder. In this condition, the immune system produces antibodies against the body’s own tissues—in this case, against the thyroid gland.

The antibodies bind to the thyroid cells and stimulate hormone production. This leads to an excessive increase in hormone levels as well as a slight enlargement of the thyroid gland.

Thyroid autonomy occurs when the thyroid gland produces hormones on its own, independent of regulation by the pituitary gland. 

This can involve individual sections of the thyroid, such as thyroid nodules, or the entire thyroid gland.

Thyroid autonomy usually develops as a result of decades of iodine deficiency. In the event of iodine deficiency, the thyroid gland attempts to compensate by growing. This leads to the formation of a goiter as well as nodular tissue changes.

Hyperthyroidism can lead to the development of a goiter © Peakstock | AdobeStock

Other possible causes of hyperthyroidism include:

• thyroiditis or
• excessive doses of thyroid hormone therapy

The most common cause of hyperthyroidism is Graves’ disease. In this condition, the body produces antibodies that mistakenly stimulate the thyroid tissue, causing the thyroid to release too many hormones. Another cause of hyperthyroidism is thyroid autonomy. In this case, there are areas or nodules in the thyroid gland that are not subject to hormonal control and produce hormones autonomously, independent of the body’s needs. Inflammation of the thyroid gland or excessive iodine intake (e.g., from iodine-containing medications or contrast agents) can also be classified as hyperthyroidism or trigger it.

This manifests itself through:

• Sweating spells
• Heart palpitations and
• Restlessness

Other typical symptoms include:

• Nervousness
• Sensitivity to heat
• Increased thirst
• Weight loss, despite an increased appetite
• Diarrhea, occasionally accompanied by vomiting
• Muscle weakness and muscle pain
• Hair loss
• Trembling in the hands
• Elevated skin temperature

Hyperthyroidism may or may not be accompanied by an enlarged thyroid gland. 

In the case of Graves’ disease, additional eye problems may occur, such as:

• Sensitivity to light
• Tearing
• Double vision
• Red eyes, as well as
• protrusion of the eyeballs, because the antibodies mentioned above target the tissue in the eye

If hyperthyroidism is suspected, a blood test is the first step. A low TSH level combined with elevated T3 and T4 levels confirms the diagnosis. To determine the exact cause of hyperthyroidism, the doctor also performs an ultrasound to identify an enlarged thyroid gland or nodules. In addition, a scintigraphy can show whether the tissue is accumulating more radioactive iodine, which may indicate autonomy or inflammation.

Treatment for hyperthyroidism usually begins with medication. Thyreostatic agents are used, which block hormone production in the thyroid cells. This medication is intended to normalize metabolic function and alleviate symptoms. A permanent cure for autonomous function or recurrences of Graves’ disease is often achieved through radioiodine therapy. In this procedure, the patient takes a capsule containing radioactive iodine, which specifically destroys the overactive tissue. Another treatment option is thyroid surgery, particularly in cases of severe thyroid enlargement or suspected malignancy.

Untreated hyperthyroidism can lead to life-threatening conditions. Thyrotoxic crisis is an extreme metabolic disturbance characterized by severe tachycardia, high fever, and altered consciousness. This often occurs when hyperthyroidism has not been adequately treated and an additional stressor, such as an infection or iodine overload, is present. In such cases, immediate additional intensive care treatment is required.

After definitive treatment such as radioiodine therapy or surgery, the thyroid gland often stops producing hormones altogether. As a result, hypothyroidism develops. However, this is no cause for concern; rather, it is an expected outcome. From then on, patients receive the hormone thyroxine in tablet form to compensate for the deficiency, which is much easier to manage than unstable hyperthyroidism.

What’s the quickest way to notice hyperthyroidism?

Early signs of hyperthyroidism often include symptoms such as a rapid heartbeat at rest, inner restlessness, and shaky hands. If you’re losing weight despite eating normally and are constantly sweating, you should have your TSH level checked.

Is Graves’ disease curable?

With Graves’ disease, there is about a 50% chance that the condition will resolve on its own after one to two years of treatment with antithyroid medication. If a relapse occurs afterward, radioiodine therapy or surgery is recommended.

What foods should you avoid if you have an overactive thyroid?

People with hyperthyroidism should be careful not to consume excessive amounts of iodine. Seafood, seaweed, or iodine tablets can further stimulate hormone production and worsen the symptoms of hyperthyroidism.

Can stress trigger hyperthyroidism?

Stress is not a direct cause, but if a person has a predisposition (such as Graves’ disease), it can trigger a flare-up or intensify symptoms like a racing heart.

How long does drug therapy last?

Drug therapy with thyreostatics for Graves’ disease usually lasts 12 to 18 months. In cases of autonomous thyroid nodules, it is often used only to prepare the patient for radioiodine therapy or surgery.

Is radioiodine therapy dangerous to those around the patient?

During treatment with radioactive iodine, the patient usually stays in a specialized hospital ward for a short time. These safety measures minimize radiation exposure to others.

What happens if hyperthyroidism occurs during pregnancy?

Hyperthyroidism during pregnancy must be closely monitored, as it can increase the risk of complications. There are specific medications for treatment that are largely safe for the baby.

Which specialists perform the diagnosis and treatment?

Endocrinologists are responsible for the thyroid gland, while nuclear medicine physicians handle diagnostics and radioiodine therapy.