Symptoms

Those affected notice a physical and mental drop in performance, are lacking in drive and slow down in their movements and thought processes. Often the patients are disinterested in environmental events, which is also reflected in their facial expressions. The patients’ sensitivity to cold is increased (=cold intolerance) and their skin is pale, cool, scaly and dry, as well as their hair is dry and brittle.

The patients’ heart rate is slowed down (= bradycardia) because the heart is less sensitive to catecholamines (=hormones, which include adrenaline, for example), which cause an increase in heart activity (see cardiac dysrhythmia). Although the reflex of the Achilles tendon can be triggered, it occurs more slowly. Patients suffer increasingly from constipation (=obstepation) and have a rough, hoarse voice.

Since the cholesterol levels of the patients are elevated, an earlier onset of arteriosclerosis is possible. Menstrual disorders and infertility can be observed in affected girls and women. Psychological symptoms can occur and show themselves in the form of depression, lack of drive and slowing down.

Patients may gain weight due to a generalized myxedema. This myxedema is caused by glycoproteins (=proteins with a sugar residue in the chemical structure) that are stored under the skin. These proteins have an osmotic effect, i.e. they attract water, which leads to water retention in the body. This results in weight gain.

Diagnosis

Hypothyroidism is determined on the basis of the clinical symptoms presented by the patient and laboratory tests. If the primary form of hypothyroidism is present, the concentration of the thyroid hormone T4 in the blood is reduced, while that of TSH and TRH is increased. In the secondary form, however, the thyroid hormone concentration and TSH levels are reduced and TRH is elevated.

In the tertiary hypothyroidism, all the hormones of the regulatory circuit are only present in greatly reduced concentrations. If the patient has an autoimmune disease of the thyroid gland, in 95% of cases autoantibodies against an enzyme (=biological catalyst) of the thyroid cells can be detected.An autoimmune process can be diagnosed by means of an ultrasound examination of the thyroid gland and a possible taking of tissue samples. Another diagnostic option is scintigraphy: Here, one makes use of the thyroid’s ability to store iodine and incorporate it into the thyroid hormones. By administering a radioactive substance via the vein, which is coupled to iodine, the function of the thyroid gland can be checked: A strongly reduced or missing storage of the radioactively marked iodine in the thyroid tissue indicates an underfunction of the organ: Few thyroid cells are active, so little iodine is needed for the production of thyroid hormones and is therefore not absorbed into the organ.