What is the permanent solution for hypothyroidism

Thyroid can afflict children

In order to detect these and other congenital diseases at an early stage, newborn screening is offered in Germany just a few days after birth. During the examination, the thyroid stimulating hormone (TSH) is determined in a drop of blood taken from capillary heel blood.


Blood is taken between the 4th and 7th day of life. If the TSH concentration is significantly increased, this indicates a congenital hypothyroidism. The limit values ​​vary between 15 and 25 mU / l, depending on the method used to determine TSH and the day the blood was taken (5). "If hypothyroidism is proven, it is extremely important to give the parents the right advice," explained Privatdozent Dr. Heiko Krude, Institute for Experimental Pediatric Endocrinology at Charité Berlin, at a thyroid congress (9). It is not easy to make parents aware that their healthy-looking baby suffers from a serious chronic illness and needs therapy throughout his life.


Finely regulated organ


The thyroid produces two hormones that influence metabolism, L-thyroxine (levothyroxine, tetraiodothyronine, T4) and triiodothyronine (liothyronine, T3), as well as the peptide hormone calcitonin, which is involved in the regulation of calcium levels. The epithelial cells of the thyroid gland (thyrocytes) and a protein-like substance (colloid) in the cavities of the thyroid gland (follicles) are involved in the production and storage of T3 and T4. Most of the T3 circulating in the blood arises from the deiodination of T4 in the periphery. The physiologically active hormone is T3.


Thyroid hormone secretion is controlled by the hypothalamic-pituitary system. If the hormone concentration in the blood is low, the hypothalamus releases thyrotropin-releasing hormone (TRH), which promotes the release of the anterior pituitary hormone thyroid-stimulating hormone (TSH, thyrotropin). TSH in turn stimulates the thyroid gland to release T3 and T4 into the blood. In a negative feedback mechanism, an increased concentration of the two thyroid hormones in the blood leads to an inhibition of the anterior pituitary and hypothalamus.


Congenital malfunctions


The most common cause of congenital hypothyroidism is a deformity of the thyroid gland. It can be completely absent (athyroidism), only incompletely developed (hypoplasia) or placed below the tongue (sublingual ectopia). Sometimes the malformation is accompanied by additional malformations of other organs, especially the central nervous system. In these patients, despite timely diagnosis and therapy, it is usually not possible to normalize mental development. Hypofunction can also be caused by a disruption in thyroid hormone synthesis. The thyroid is then normal in size. However, this form of hypofunction is relatively rare; it affects around 15 to 20 percent of cases (5).


As a rule, the mother compensates for the needs of her sick child during pregnancy. If it produces sufficient thyroid hormones, there are usually no clear symptoms of hypothyroidism in the newborn, although the placental barrier prevents the hormones from crossing (15). If, on the other hand, the mother suffers from an overactive thyroid, the unborn child is protected from excessive maternal hormone levels by a placentally expressed deiodase (7).


However, there are also congenital overactive thyroid glands (3). The pregnant woman usually suffers from Graves' disease, in which the entire thyroid gland is evenly enlarged. It is an autoimmune disease in which antibodies are formed against thyroid tissue (thyroid stimulating immunoglobulins, TSIs). These antibodies act like TSH and cause sustained stimulation of the thyroid gland. The negative feedback mechanism between the pituitary and thyroid glands is intact, so that the increased T3 and T4 concentrations lead to a decrease in TSH secretion. The cause has not yet been clarified.


The increased concentration of thyroid hormones in Graves' patients increases energy expenditure, body temperature and heart rate. In addition, there is excitability, weight loss, tremors (tremor), warm, damp skin and increased sweating. A so-called exophthalmos is typical, i.e. the eyeballs protrude.


If the mother's antibodies are transferred to the child, overstimulation of the child's thyroid can result. As a result of the resulting high T3 and T4 blood levels, the TSH concentration is reduced in contrast to hypothalamic-pituitary-induced hyperthyroidism. This congenital overactive thyroid is very rare. Only 0.2 percent of pregnant women suffer from Graves' disease, and only one percent of their children suffer from this autoimmune disease permanently.


Hashimoto's thyroiditis


All known thyroid diseases are possible in later childhood and adolescence. "Due to the improved iodine supply, iodine deficiency diseases are rather rare today," explained Krude (9). Also, hot and cold lumps and thyroid cancer are not common in children.


On the other hand, under and overfunction are more common, mostly as a result of an autoimmune thyroid disease such as Hashimoto's thyroiditis. The incidence of the disease in Western Europe is 1 to 2 percent of the total population; Subclinical courses are more common and range from 6 to 8 percent (16). Hashimoto's thyroiditis is often associated with other autoimmune diseases such as type 1 diabetes. Girls generally get sick earlier than boys.


As with Graves' disease, antibodies against thyroid tissue can be detected in Hashimoto's thyroiditis. In contrast to Graves' disease, however, the antibodies trigger a chronic inflammatory process in the thyroid tissue. In the early stages of the disease, diseased thyroid cells initially transfer more hormones into the blood; therefore hyperthyroidism occurs first. In the long term, however, the hyperthyroidism turns into an underfunction due to permanent cell death (1).


Careful diagnosis


"Thyroid disorders can manifest themselves in many ways in children and adolescents," said Dr. Beate Quadbeck, doctor for endocrinology and diabetology, Düsseldorf, at the symposium (9). The characteristic symptoms change with age (Table 1). Diseases like Hashimoto's thyroiditis can show symptoms of both hypothyroidism and hyperthyroidism. This makes diagnosis more difficult (13).