Overactive thyroid gland (hyperthyroidism)

In people who have an overactive thyroid (known medically as hyperthyroidism), the thyroid gland produces too much of the thyroid hormones triiodthyronine (T3) and thyroxine (T4). This overproduction of thyroid hormones speeds up the metabolic processes in the body. Hyperthyroidism mainly occurs in women and the elderly.

The increased production of thyroid hormones is reflected in an excessively low level of the regular hormone TSH and a simultaneous increase of one or both levels of the thyroid hormones T3 and T4. In incipient or latent hyperthyroidism, only the TSH value is reduced, while the T3 and T4 values remain in the normal range.


Hyperthyroidism manifests itself in the form of numerous symptoms. These include:

  • an enlarged thyroid gland (known as a struma or goitre)
  • restlessness
  • nervousness
  • irritability or mood swings
  • heart palpitations or racing pulse (rapid heartbeat)
  • increased blood pressure
  • increased thirst
  • increased sweating
  • clammy skin
  • hypersensitivity to heat
  • diarrhoea and occasionally vomiting
  • weight loss despite increased food intake
  • hair loss
  • muscle weakness, muscle pain, muscle fatigue
  • trembling
  • For women: menstrual disorders


The increased production of thyroid hormones by individual nodules (autonomous adenoma) or by the thyroid gland as a whole may have various causes, including:


If it is suspected that the patient is suffering from hyperthyroidism, the doctor will begin by ascertaining the patient’s medical history and asking questions about possible thyroid disorders in the family, or about the patient’s eating habits. This will be followed by a physical examination, which includes palpation of the neck.

As a rule, the physical examination will be followed up with a blood test to measure the concentration of the thyroid hormones T3 and T4 as well as the hormone TSH (thyroid-stimulating hormone). In patients with hyperthyroidism, TSH levels are reduced, while T3 and T4 concentrations are increased.

In the course of further diagnostics, the doctor may also refer the patient for the following examinations:

  • ultrasound examination (sonography)
  • urine test to determine excessive iodine intake
  • thyroid scintigraphy (used to examine the functioning of the thyroid gland in more detail)
  • fine-needle biopsy to take a tissue sample


Patients should not take the diagnosis of hyperthyroidism lightly. This is a serious condition that should be treated by a specialist in internal medicine or an endocrinologist.

Generally speaking, the following treatment options are available to doctors (always depending on the severity of the hyperthyroidism, as well as the age and general condition of the patient):

  • Medicinal treatment using ‘thyroid blockers’ (thyrostatic agents): drugs that reduce the circulation of thyroid hormones in the blood. During this type of treatment, regular blood tests are required to check whether the medication is working properly.
  • Radioiodine therapy: Here, the patient receives radioactive iodine, which is stored in the thyroid gland. Cells that produce more thyroid hormones absorb a high quantity of it. When the radioactive iodine decays, radiation is produced which destroys these cells, resulting in a decrease in hormone production.
  • An operation to completely or partially remove the thyroid gland.
  • The administration of drugs to relieve the symptoms of hyperthyroidism.

As diet also plays an important role in hyperthyroidism (many of those affected lose weight as a result of an accelerated metabolism), it is important to consume enough calories while eating a balanced and varied diet. For this reason, it is advisable to work out a personal meal plan together with your doctor.

In addition, patients with hyperthyroidism should avoid consuming excess iodine.


Most thyroid disorders require life-long monitoring, and many require long-term treatment. The time intervals and scope of the necessary checks depend on the exact findings for each individual patient and are determined on a case-by-case basis.


How does hyperthyroidism manifest itself in the elderly?

In older people, hyperthyroidism usually manifests itself differently than in younger people. Many of the typical symptoms may be absent, and the symptoms present are usually less pronounced.

How does hyperthyroidism affect patients with diabetes?

If a patient has diabetes (known as diabetes mellitus) in addition to hyperthyroidism, this has a further effect on the patient’s body. The cells no longer react as well to insulin (a pancreatic hormone that regulates blood sugar levels) and therefore absorb less sugar (glucose) from the blood, which increases the condition known as ‘insulin resistance’ in diabetic patients. At the same time, hyperthyroidism can increase the release of sugar from the liver. As a result of these two processes, blood sugar levels rise and diabetics with untreated hyperthyroidism need more insulin than usual.

How is hyperthyroidism classified?

Hyperthyroidism is classified according to its degree of severity.

  • Latent or incipient hyperthyroidism is an early stage of hyperfunction in the thyroid gland: there are still normal levels of T3 and T4 in the blood; it is just the TSH level that is lower.
  • Manifest hyperthyroidism is a persistent hyperfunction of the thyroid. The symptoms can be more or less obvious.
  • If there is a significant surplus of thyroid hormones, a condition known as thyrotoxicosis develops, which in the worst case can lead to a life-threatening thyrotoxic crisis or ‘thyroid storm’. A thyrotoxic crisis is an emergency and requires immediate intensive medical care.

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