The thyroid is a small parenchymatous organ located in the lower half of the front door. Its weight is only about 20 grams. It belongs to a group of glands with internal secretion, which secrete their hormones directly into the blood. The two main thyroid hormones are thyroxine (T4) and triiodothyronine (T3). Their production is regulated pituitary hormone thyrotropin (TSH). If you reduce the production of T3 and T4, the pituitary produces more TSH amount of effort to stimulate the thyroid to excess work. If the thyroid gland can not do this, the level of TSH is increasing rapidly which can lead to goiter (increased thyroid).
Hypothyroidism is a metabolic disorder caused by decreased amounts of thyroid hormones in the body, which manifests itself with a number of symptoms. Very rarely the values of T3 and T4 may be normal or even elevated, and the error is on the tissue cells that have receptors for thyroid hormones and their effect is missing.
CAUSES AND FREQUENCY
The most common cause of hypothyroidism is Hashimoto's thyroiditis, chronic inflammation of the thyroid. It is an autoimmune disease in which, due to errors in identification, the body produces antibodies to different components of the thyroid. These antibodies gradually lead to irreversible damage to the thyroid and the slow decline of its functions. Autoimmune diseases in general are about seven times more common in women than in men, so it is with this disease. They can be affected by all age groups, and very often there is a predisposition familjarna. It affects a few percent of the population, slightly more women of 40-60 years.
Hashimoto's thyroiditis is often occurs in combination with other autoimmune diseases (eg rheumatoid arthritis, lupus eritematozes, diabetes, etc..).
Today is a very common cause of hypothyroidism radioactive iodine I-131, which is sometimes used to treat hyperthyroidism (increased thyroid operation).
Hypothyroidism can cause thyroid surgery. It is an inevitable consequence of complete removal of the glands in the case of thyroid cancer, and often occurs after a partial resection of benign thyroid tumors, hyperthyroidism, cystic formations and the like.
Hypothyroidism can be caused by a rare disease of the pituitary and hypothalamus (secondary and tertiary hypothyroidism). They can be caused by radiation doors, some medications, etc..
Separate entity is congenital hypothyroidism, which is now fortunately discovered already in maternity routine determination of TSH in the blood of the newborn.
All the symptoms are a consequence of reduced metabolism. Patients gain weight, have slowed, drowsy, listless, they constantly cold. Constipation often occurs, the skin becomes pale, and in severe cases there are edema and disorders of the heart. The hair is dry and difficult to comb, the voice is hoarse because of vocal cord edema, developed hearing loss, leads to menstrual dysfunction and infertility in men and women. It is particularly dangerous as these symptoms in Hashimoto thyroiditis develop gradually, so that patients often get used to them.Many of them remain unrecognized until advanced disease stage. It is important to note that the majority of patients expressed no complaints and some of them are hypothyroidism detected by chance.
TESTS AND RESULTS
From the blood is critical to determine the values of the peripheral thyroid hormones (T3 and T4) and TSH, including TSH was significantly increased the most important indicator of hypothyroidism. The values of T3 and T4 sometimes depend on the quantity of proteins that serve as their carriers, and can cause falsely elevated values. In these cases it is better to set free, the unbound proteins, hormones (FT3 and FT4). Direct indication of slow metabolism is increased blood cholesterol levels, and increased its value is sometimes the first sign of possible hyperthyroidism. In case of suspicion of Hashimoto's thyroiditis is desirable to determine the concentration of antibodies to the thyroid. In our conditions it is possible to determine antibodies to thyroglobulin and peroxidase.
It is very important to do an ultrasound to see the thyroid volume and appearance of thyroid tissue. In Hashimoto's thyroiditis in the thyroid gland is usually very inhomogeneous, hypoechogenic and uneven contours, and in the states after surgery seen a significant reduction of glandular tissue. Sometimes, when you can not establish the existence of thyroid tissue, it can be done scintigraphy with Tc-99m pertechnetate.
Regardless of its cause, in the case of hypothyroidism need to take replacement therapy - thyroid hormones. On the market there thyroxine tablets, which need to be taken every morning, at least half an hour before eating. The therapy is being introduced gradually, and the required dose of thyroxine is usually defined after several months of use. Following the introduction of the drug or dose changes, it takes some time to create a balance between the pituitary and new levels of thyroxine in the blood, so that thyroid hormones and TSH are determined at least 6 weeks of the change. It is important to say that this must be treated and subclinical hypothyroidism (normal T3 and T4, elevated TSH). In tudnoći and during breastfeeding medication is also necessary to take, but the dose must often be increased due to increased need for thyroxine. Thyroxine is quite safe for the fetus.
Prognosis is excellent if replacement therapy is taken regularly in the dose prescribed by your doctor. Patients should be aware that therapy with thyroxine often lifelong. In the case of Hashimoto thyroiditis need for thyroxine is usually gradually increases and the dose must be increased up. In the case of postpartum (after birth in the mother) after subacute thyroiditis, and thyroid inflammation, hypothyroidism is usually transient.
If replacement therapy is properly taken no complications. They may occur in case of not taking the therapy or in case of overdose with thyroxine. In the first case, the symptoms of hypothyroidism deepen which can lead to its most severe form - which miksedemske (mortality 80%). If thyroxine is taken in excessive amounts leads to the development of iatrogenic (caused by medication) hyperthyroidism with all its simptomoma (sweating, nervousness, weight loss, tachycardia, etc..). It is therefore important that all these patients in the control of a doctor to monitor thyroid hormone and TSH at least annually.
In the case of almost all causes of hypothyroidism are no real preventive measures and its origin is practically impossible to prevent. It is important to recognize it and help prevent complications.
In congenital hypothyroidism as a result of unrecognized disease occurs cretinism, which is thankfully now increasingly rare due to the early determination of TSH, but the maternity unit, resulting in timely initiation of taking replacement therapy in hypothyroidism of newborns.