The thyroid gland (medical term: thyroid gland) is a vital, small hormone gland located in the front of the neck below the larynx that produces vital thyroid hormones. It is essential for metabolism, growth and maturation of the body and involved in the regulation of various bodily functions. It continuously releases a certain amount of thyroid hormones into the blood. As soon as the metabolism requires more energy, for example in cold weather, during growth or during pregnancy, the thyroid cranks up its hormone production.
When the thyroid gland no longer functions properly, a general distinction is made between hypothyroidism and hyperthyroidism.
The hypothyroidism/ hypothyroidism
Underactive thyroid or hypothyroidism is the term doctors use to describe insufficient hormone production by the thyroid gland. Due to the lack of hormones, all metabolic processes in the body are slowed down and performance is reduced. Hypothyroidism is one of the most common metabolic diseases, which affects women more often than men.
Hypothyroidism can occur at three levels: due to dysfunction of the thyroid gland itself, due to impaired TSH production in the pituitary gland, or due to insufficient TRH secretion by the hypothalamus.
Accordingly, physicians distinguish between different forms of hypothyroidism.
By far the most common cause of hypothyroidism originates from the thyroid gland itself. In this case, physicians speak of primary hypothyroidism. The causes can be congenital or can occur in the course of life.
Some children lack a thyroid gland from birth (athyroidism). In other children, the thyroid gland is undeveloped (thyroid dysplasia), or there are errors in the production of thyroid hormones.
In most cases, acquired hypothyroidism is caused by chronic inflammation of the thyroid gland. This so-called Hashimoto's thyroiditis is an autoimmune disease: the body produces special antibodies that destroy its own thyroid tissue. As a result, it can no longer produce enough thyroid hormones. However, the reasons why the body produces these antibodies are still unclear. Learn more about Hashimoto's disease here.
Sometimes iodine deficiency also contributes to the development of acquired hypothyroidism: The trace element is needed by the thyroid gland to produce thyroid hormones. People who take in too little iodine through their diet can develop an extreme iodine deficiency and thus hypothyroidism in the long term.
In addition, hypothyroidism can occur after radioiodine therapy or thyroid surgery. This is the case when a lot of thyroid tissue has been destroyed or removed during treatment and there is no or too little hormone replacement with medication. It is also possible that medications used to treat hyperthyroidism have been overdosed or that hyperthyroidism is causing hypothyroidism.
In secondary hypothyroidism, the cause of the hypothyroidism lies in the pituitary gland. This produces too little TSH, the hormone that stimulates the thyroid to produce hormones. In this case, physicians speak of pituitary insufficiency. In contrast to primary hypothyroidism, in the secondary form not only the T3/T4 blood values but also the TSH value are elevated.
Far rarer is tertiary hypothyroidism. This is caused by the hypothalamus. This in turn produces too little of the hormone TRH, which ultimately regulates thyroid hormone production via the pituitary gland.
Symptoms of hypothyroidism
As a rule, hypothyroidism develops gradually in adulthood. At first, there are few or no symptoms. Usually, the symptoms only become noticeable when the hypothyroidism becomes more severe. The following symptoms do not all have to occur and can also vary in severity.
- Extreme fatigue, excessively fast exhaustion
- Weight gain
- Depressive mood
- Increased susceptibility to infections
- Cool, dry skin
- Concentration disorders
- Lack of drive
- Sensitivity to cold
- Loss of appetite
- Puffy face, swollen tongue and eye areas
- Dull hair, hair loss
- Headache & Migraine
- Menstrual irregularities, reduced fertility or menstrual cramps.
Hypothyroidism can be detected or ruled out relatively quickly by determining basal thyroid levels (T4, T3, TSH) in the blood.
The determination of special thyroid antibodies in the blood, an ultrasound examination of the thyroid gland and possibly also a scintigram are further examinations to determine the cause of hypothyroidism.
The hormone deficiency that occurs with hypothyroidism can be compensated for by hormone tablets. Patients usually take these for the rest of their lives. If the dosage is correct, neither the quality of life nor the life expectancy of the patients is restricted. Doctors also refer to this as replacement or substitution therapy.
The preferred drug for the treatment of hypothyroidism is L-thyroxine. It is a synthetic hormone that acts like the natural thyroid hormone thyroxine (T4). In the body, it is partially converted into the thyroid hormone T3.