resistance syndrome

August 12, 2017 17:51 | Genetic Diseases

resistance syndrome (insensitivity) to the thyroid hormone are relatively rare, are transmitted in an autosomal dominant inheritance type.Normally, when the amount of thyroid hormone in the blood decreases formation pituitary hormone thyrotropin (brain iron).This hormone acting on the thyroid gland, causing an increase in the formation of its hormones.Thus, the normal operating principle of feedback: by increasing one decreases the amount of another hormone, and vice versa.Due to this principle is provided by maintaining the level of hormones in human serum at approximately a constant level.In syndromes of resistance to thyroid hormones is determined by a paradoxical combination of high levels of thyroid hormone to adequately increased level of thyroid-stimulating hormone, t. E. There is an infringement of the principle of feedback.Furthermore, in these syndromes are no typical symptoms of hyperthyroidism.At the heart of the development of thyroid resistance syndrome is a violation of the sensitivity of

various tissues to thyroid hormone.By the end of the 1990s.the world described a little more than 200 different varieties of these syndromes.

total (generalized) insensitivity to thyroid hormone includes central and peripheral resistance.Central resistance is that an increase in the level of free thymic hormones does not occur adequately reduce pituitary hormone thyrotropin (TSH), and therefore its serum concentration remains within the normal range, or may be somewhat higher.Peripheral resistance is in violation of the sensitivity of the body's peripheral tissues to the action of thyroid hormones.

Currently, most identified cases falls into a generalized form of the disease.For those people who do not receive any treatment, it is often determined by normal metabolism, which occurs due to the high levels of circulating free thyroid hormones.Pituitary resistance to thyroid hormone is less common form of the syndrome.With him there are elevated levels of free thyroid hormones (thyroxine and triiodothyronine), as well as normal (with respect to this case inappropriately high) level of thyroid-stimulating hormone.This syndrome is manifested all the signs of hyperthyroidism (see. Above).Thus, for the pituitary thyroid resistance, unlike the generalized symptoms characteristic of hyperthyroidism.When the dead body's peripheral tissues to thyroid hormone to normal background levels of thyroid-stimulating hormone and thyroid hormones, there are signs of hypothyroidism, t. E. A reduced amount of serum thyroid hormones.By the manifestations of hypothyroidism include: gradual weight gain, dry, thickening of the skin, changing its color ( "wax", "peach" and "jaundice" skin color), coarsening of facial features, increase the size of shoes, blurred speech.From time to time, particularly after loads, there may be pain in the right upper quadrant, constipation, chest pain, shortness of breath when walking.Women often disrupted menstrual function.It may be noted a significant decline in intelligence.

diagnosis of generalized resistance to thyroid hormone is placed in the presence of three characteristic symptoms (triad): elevated levels of thyroid hormones in the blood serum of normal or increased content of thyroid-stimulating hormone, peripheral euthyroidism (normal levels of thyroid hormones in the blood) or hypothyroidism (decreased levelhormones of the thyroid gland).In people with the disease do not have symptoms of hyperthyroidism such as weight loss, poor tolerance of heat, hand tremors, irritability.Due to a compensatory increase in the level of thyroid hormones people do not complain, characteristic of hypothyroidism, as high levels of circulating hormones in the blood of the thyroid gland compensates generalized numbness in most body tissues, thus creating a euthyroid state.

In patients with pituitary insensitivity (brain iron) in the blood observed the same violations, as well as in generalized form.The difference is that in this type of disease they have signs and symptoms associated with hyperthyroidism, such as weight loss, hand tremors, increased nervous irritability, heart palpitations, insomnia, poor tolerance of heat.When stability pituitary sensitivity to hormones reoidnym Ti-reduced and in most peripheral tissues preserved normal hormonal responses.

Antenatal diagnosis of generalized resistance to thyroid hormone is based on the identification of mutations by examining amniotic fluid.

treatment.The vast majority of individuals with generalized resistance to the hormones of the thymus gland are normal or slightly elevated levels of thyroid stimulating hormone in the blood and significantly elevated levels of thyroid hormones.So people in general should not receive any treatment aimed at reducing the level of thyroid-stimulating hormone.

drug of choice for pituitary sustainability is triiodothyroacetic acid.The drug is taken in divided doses to achieve a permanent suppression of secretion of thyroid-stimulating hormone.However, despite the suppression of its formation, the treatment of hyperthyroidism symptoms triiodothyroacetic acid partly retained.

most difficult submitted treatment and diagnosis of peripheral resistance (stability) to the thyroid hormone in connection with the actual lack of laboratory criteria by which to assess the adequacy of therapy with thyroxine (thyroid hormone).