Thyroid-stimulating hormone, TSH, is a peptide hormone secreted by the anterior pituitary gland in the brain. TSH is responsible for the regulation of the thyroid, an extremely important endocrine gland located at the front of the base of the neck. The thyroid is stimulated by TSH to produce two additional hormones, T3 and T4. These hormones are secreted into the bloodstream and are vital for the healthy growth and development of children.
Normal TSH Levels
The normal range of TSH levels is dependent on the age of the child. For full-term newborns, the acceptable range of TSH levels is 0.9 to 7.7 µU/ml. For children age one through the age of puberty, TSH levels should fall somewhere between 0.6 to 5.5 µU/ml. For teenage children and adults, the normal range of TSH levels is 0.5 to 4.8 µU/ml.
Testing
Testing for the levels TSH is performed in order to determine if the thyroid gland is functioning properly. The test is a simple blood test and is the best method for the detection of thyroid disorders in children, as well as in adults.
Hypothyroidism
Hypothyroidism is characterized by the production of insufficient amounts of T3 and T4. This condition can arise due to several physiological reasons. In some cases, the thyroid gland did not properly form during fetal development. Therefore, TSH from the pituitary cannot stimulate the release of T3 and T4. In other cases, the thyroid is properly formed but an immune disorder can cause the body to make antibodies against the thyroid gland. This would also decrease T3 and T4 levels. Symptoms of hypothyroidism in infants and children include decreased growth, poor development and poor muscle tone. Dry mouth, skin dryness and constipation may also occur. Levels of TSH in children with hypothyroidism are often high. Since T3 and T4 levels are low, the pituitary will increase production of TSH in an attempt to increase secretion of T3 and T4 from the thyroid.
Hyperthyroidism
Hyperthyroidism is less common than hypothyroidism. Hyperthyroidism is characterized by a rapid heart beat, decreased attention span, sweating, flushed skin and nervousness. Due to the constant stimulation of the thyroid gland, children with hyperthyroidism may development a visibly enlarged thyroid gland, known as a goiter. In children diagnosed with hyperthyroidism, TSH levels are often low due to the constant overproduction of T3 and T4 from the thyroid. Since the gland is producing these hormones in excess, it does not need the stimulation provided by TSH, and TSH levels drop.
Treatment
Hormone replace therapy is often used to treat disorders of the thyroid gland. For hypothyroidism, replacement therapy involves daily injections of T4 since it has a longer life span in the body than T3. These injections are usually needed for the rest of the child's life. Anti-thyroid drugs are commonly used to to treat hyperthyroidism. These drugs attempt to block the effect of T3 and T4 on tissues. Surgical removal of part of the thyroid gland may also an effective treatment option for children with hyperthyroidism.
