Hypothyroidism: An Overview of Information

Insufficient level of thyroid hormones in organs and tissues leads to the development of such a pathological condition as hypothyroidism - a disease first described by V. Gull in 1873. The term "myxedema", owned by VM Ordu (1878), means only mucous edema of the skin and subcutaneous tissue. It is traditionally used to characterize the most severe forms of hypothyroidism, accompanied by a kind of universal mucous edema.

[1], [2], [3], [4], [5], [6], [7], [8]

The cause and pathogenesis of hypothyroidism

In the overwhelming majority of cases (90-95%), the disease is caused by a pathological process in the thyroid itself, which reduces the level of production of hormones (primary hypothyroidism). Violation of the regulatory and stimulating effect of pituitary thyrotropin or hypothalamic releasing factor (thyreoliberin) leads to secondary hypothyroidism, which is significantly inferior to primary hypothyroidism. The issue of peripheral hypothyroidism, arising either in connection with the disturbance of the metabolism of thyroid hormones at the periphery, in particular, the formation of T ₄ not T ₃, but inactive, reversible T ₃, or as a result of a decrease in the sensitivity of nuclear receptors of organs and tissues to thyroid hormones.

Causes and pathogenesis of hypothyroidism

Symptoms of hypothyroidism

Primary hypothyroidism, represented mainly by its "idiopathic" form, is more frequent in women 40-60 years of age. In recent decades, there has been an increase in all autoimmune diseases, including hypothyroidism. In this regard, the age range has significantly expanded (the disease is observed in children, and in adolescents, and in the elderly), and sex began to wear off. Of particular importance in terms of diagnosis, and in terms of treatment, acquired hypothyroidism in elderly patients, in which a number of general nonspecific symptoms can be mistakenly attributed to natural age involution or organ pathology.

Symptoms of pronounced hypothyroidism are very polymorphic, and patients present a lot of complaints: sluggishness, sluggishness, fatigue and decreased performance, sleepiness during the day and disturbance of night sleep, memory impairment, dry skin, swelling of the face and limbs, fragility and striation of the nails, hair loss, increase body weight, paresthesia, often abundant or poor menstruation, sometimes amenorrhea. Many people note persistent pain in the lower back, but this symptom disappears as a result of effective thyroid therapy, does not attract the attention of doctors and is usually regarded as a manifestation of osteochondrosis.

Diagnosis and differential diagnosis of hypothyroidism

Diagnosis of severe hypothyroidism, especially in those who underwent surgery on the thyroid, who received treatment with radioactive iodine, which caused autoimmune diseases, does not cause any special difficulties. It is more difficult to identify light forms with scanty, not always typical clinical symptoms, especially in elderly patients, where it is easy to suspect cardiovascular failure, kidney disease, etc. In young and middle-aged women, a number of symptoms similar to hypothyroidism are observed in the syndrome of idiopathic edema .

The diagnosis of primary hypothyroidism is specified by a number of diagnostic laboratory tests. Functional deficiency of the thyroid gland is characterized by a decrease in the blood level of iodine bound to the protein - SbI, butanol extractable iodine and the degree of absorption of ¹³¹ 1 by the thyroid gland, mainly after 24-72 h (at a rate of 25-50% of the administered dose).

[9], [10], [11], [12], [13]

Treatment of hypothyroidism

The main method of treating all forms of hypothyroidism is substitution therapy with thyroid medications. TSH preparations have allergic properties and are not used as a remedy for secondary (hypophysial) hypothyroidism. Recently, there have been studies on the efficacy of intranasal (400-800-1000 mg) or intravenous (200-400 mg) administration of TRH for 25-30 days in patients with secondary hypothyroidism caused by a defect in endogenous stimulation and the secretion of biologically inactive TSH.

The most common domestic drug is thyroidin, obtained from the dried thyroid gland of cattle in the form of pills of 0.1 or 0.05 g. The amount and ratio of iodothyronines in thyroidin varies considerably in different batches of the drug. Approximately 0.1 g of thyroidin contains 8-10 μg of T ₃ and 30-40 μg of T ₄. Unstable composition of the drug makes it difficult to use and evaluate its effectiveness, especially at the first stages of treatment, when exact minimum doses are needed. The efficacy of the drug is reduced, and sometimes completely eliminated, because of its poor absorption of the mucosa of the gastrointestinal tract.