Brief overview
- Common symptoms: Fatigue, weight gain, constipation, low mood, feeling cold.
- Investigations: Blood test for thyroid levels, ultrasound, scintigraphy.
- Treatment: L-thyroxine tablets
- Attention: Check hormone dose regularly (TSH value), correct treatment especially important during pregnancy
- Specialist: internal medicine (endocrinology), gynecology (for pregnant women), family doctor
Hypothyroidism: symptoms
In hypothyroidism, the thyroid gland produces too little of the two hormones thyroxine (T4) and triiodothyronine (T3). They influence almost all metabolic processes in humans and are therefore vital. While a mild thyroid insufficiency usually causes hardly any symptoms, a more severe hormone deficiency significantly slows down almost all metabolic activity. This causes sometimes severe symptoms.
Common symptoms
Common symptoms of hypothyroidism include poor performance, poor concentration and fatigue. Affected individuals often feel low in energy and depressed.
An increased sensitivity to cold is also typical in hypothyroidism. The skin can be cool, dry, rough and thickened; sometimes yellowish discolorations occur (storage of the dye carotene!).
Externally, hypothyroidism can cause signs such as a swollen face with thickened lips and enlarged tongue, swelling around the eye sockets and thus slit-like narrowed eyelids.
The reason for the doughy swollen skin are special carbohydrate chains, so-called glycosaminoglycans. In hypothyroidism, they are no longer broken down properly and accumulate in the connective tissue. Physicians speak of so-called myxedema. The vocal cords may also be affected, causing a rough, hoarse voice.
Hypothyroidism can also cause the following symptoms:
- Depressive mood
- Constipation
- Slowing of the heartbeat (bradycardia), enlargement of the heart, low blood pressure
- Circulatory disturbances with sensory disturbances (such as “formication”)
- Menstrual disorders in women
- Restrictions of sexual desire (libido), fertility and potency (erectile dysfunction = impotence)
- Goiter (goiter)
Sometimes hypothyroidism changes blood parameters such as the amount of hemoglobin and red blood cells. While these parameters may decrease in hypothyroidism, cholesterol levels are often elevated. This can lead to early hardening of the arteries (atherosclerosis).
Symptoms in elderly people
In the elderly, the only symptoms often observed in hypothyroidism are sensitivity to cold, poor performance or depression. Not infrequently, such signs are misinterpreted as signs of aging, dementia or depression, and the real cause – hypothyroidism – remains undetected.
Symptoms in babies
Babies with congenital hypothyroidism show typical symptoms right after birth: they move little, do not want to drink, and have weak muscle reflexes. Constipation and prolonged neonatal jaundice may also indicate hypothyroidism.
If the hormone deficiency is left untreated, growth retardation, delayed mental development and speech development disorders will occur as the condition progresses. This severe form of untreated hypothyroidism is called cretinism.
Latent hypothyroidism: symptoms
In latent (“hidden”) hypothyroidism, the concentration of thyroid hormones is not (yet) decreased, only the TSH level is increased. Therefore, symptoms such as poor performance and poor concentration, fatigue, etc. do not occur here or only to a lesser extent.
Hypothyroidism: Causes and risk factors
The causes of hypothyroidism can arise at any of the three levels: through disturbances in the function of the thyroid gland itself, through disturbed TSH production in the pituitary gland, or through insufficient TRH secretion from the hypothalamus. Accordingly, physicians distinguish between different forms of hypothyroidism:
Primary hypothyroidism
By far the most common cause of hypothyroidism lies in the thyroid gland itself. Doctors then speak of primary hypothyroidism. The causes may be congenital or may occur later in life:
Congenital hypothyroidism
Some children are born without a thyroid gland (athyroidism). In others, the thyroid gland is defectively developed (thyroid dysplasia), or errors occur in the production of thyroid hormones. Also, if a pregnant woman receives too high a dose of therapy for hyperthyroidism of her thyroid gland, the child may develop hypothyroidism in the womb.
Acquired hypothyroidism
Acquired hypothyroidism can also be the result of previous medical treatment. For example, treatment of hyperthyroidism sometimes overshoots the mark: both irradiation with radioactive iodine and treatment with drugs for hyperthyroidism can disrupt hormone production so permanently that hyperthyroidism becomes hypothyroidism.
Thyroid surgery (for example, due to an enlarged thyroid = goiter, goiter) can also lead to hypothyroidism if there is not enough healthy thyroid tissue left.
Sometimes iodine deficiency plays a role in the development of acquired hypothyroidism: the thyroid gland needs the trace element to produce thyroid hormones. Those who take in too little iodine in their diet can develop an extreme iodine deficiency and, as a result, hypothyroidism.
Secondary hypothyroidism
In secondary hypothyroidism, the cause of hypothyroidism lies in the pituitary gland: It produces too little TSH, the hormone that stimulates the thyroid gland to produce hormones. Doctors refer to this as pituitary insufficiency. In contrast to primary hypothyroidism, in the secondary form both the T3/T4 blood levels and the TSH level are elevated.
Tertiary hypothyroidism
Even rarer is tertiary hypothyroidism, the cause of which lies with the hypothalamus. It then produces too little of the hormone TRH, which ultimately regulates thyroid hormone production via the pituitary gland.
Hypothyroidism – frequency
Approximately one percent of the population suffers from hypothyroidism. About one in 3,200 newborns is born with hypothyroidism. This is called primary congenital hypothyroidism.
In addition to these patients with manifest hypothyroidism, there are also many people who have what is called latent hypothyroidism: In them, the blood levels of thyroid hormones are normal, but TSH is elevated. This means that the thyroid gland only produces sufficient amounts of hormones when it is very strongly stimulated by the pituitary gland. Latent hypothyroidism may later develop into manifest hypothyroidism.
Hypothyroidism: examinations and diagnosis
If hypothyroidism is suspected, the doctor will first ask you about the typical symptoms and then examine you physically. For example, he may feel the texture of your skin or palpate the front of your neck, where the thyroid gland is located. This will allow him to assess its size and consistency.
A blood sample is also important. One of the most important blood values for clarifying suspected hypothyroidism is the TSH value. The concentration of this hormone in the blood reveals how much the thyroid gland needs to be stimulated to produce enough thyroid hormones. In most cases of hypothyroidism, the TSH concentration in the blood is elevated.
If the TSH level is elevated, the doctor will also determine the T4 level in the blood. If this is normal, it indicates latent hypothyroidism. However, if the T4 level is low, it is a manifest hypothyroidism. However, the physician always evaluates the hormone values individually, because different normal values apply depending on the patient’s age and weight. If physical symptoms are absent, he usually remeasures.
You can read more about hormonal thyroid values in the article Thyroid values.
Further diagnostics in hypothyroidism
Under certain circumstances, doctors may order further examinations to determine the cause of the hypothyroidism:
- Ultrasound examination: The size and condition of the thyroid gland can be determined by means of an ultrasound examination.
- Biopsy: Sometimes the doctor also takes tissue samples for analysis in the laboratory. In this way, he can find evidence of a tumor or inflammation.