Hypothyroidism call the syndrome caused by decrease in production of hormones a thyroid gland and/or reduction of their impact on target tissues. Thyroid hormones influence numerous intracellular processes, growth and development of an organism therefore their shortcoming leads to various system disturbances.
Classification of a hypothyroidism
Depending on the reasons distinguish primary, secondary and peripheral hypothyroidism. Primary hypothyroidism is connected with disturbances of structure and function of cells of the most thyroid gland. At secondary — decrease in secretion of thyritropic hormone of a hypophysis owing to pituitary or hypothalamic disturbances takes place. Peripheral — it is caused by disturbances in a peripheral exchange of thyroid hormones or emergence of resistance of target tissues to their influence.
Most often primary hypothyroidism occurs among adult population. Bring to it an idiopathic atrophy of a thyroid gland which usually develops at women in the post-menopausal period, an autoimmune thyroiditis (Hashimoto's craw) which is followed by gradual destruction of fabric of gland, a degrowth of tissue of thyroid gland owing to surgical intervention, radiation therapy of area of a neck, treatment by anti-thyroid means (mercazolil, Thiamazolum) and treatment by a radioiodine concerning a thyrotoxicosis, use of iodinated medicines (Amiodaronum, radiopaque substances, iodinated intestinal antiseptic agents) and also other medicines influencing transformations of iodine in a thyroid gland (lithium carbonate).
The hypothyroidism meets in all age groups, gradually accruing with age, is more often at women. At the same time at elderly patients essential dominance of subclinical forms over obviously outlined options of a course of a disease is observed. Frequency of a subclinical hypothyroidism at women is more senior than 50 years makes 5 — 10%, and the frequency of an explicit hypothyroidism of 1,5 — 2,0%. At men 60 years these values are more senior make 1,25% against 0,1-0,2% respectively.
Metabolic disturbances at a hypothyroidism
At a hypothyroidism disturbances of standard metabolism — reduction of consumption of oxygen and a hypothermia are noted; disturbances of protein metabolism — reduction of muscle bulk, increase of level creatine phosphokinase, anemia; a lipidic exchange — increase of level of lipoproteids and cholesterol, disturbance of an exchange of the mucopolysaccharides which are the main component of interstitial substance of fabrics — accumulation in fabrics of hyaluronic acid and a hondroitinsulfat.
Complaints and symptoms at a hypothyroidism
In most cases the disease develops gradually, complaints are not specific. Patients note physical and mental fatigue, decrease in working capacity, weakness, memory disturbances, sharply expressed drowsiness, headaches. Complaints to a chill, emergence of puffiness of the person, fragility and a hair loss on the head and on a body, dryness and a peeling of skin, decrease in hearing, change of a voice towards lower timbre are frequent. Appetite, as a rule, does not change, however the increase in weight is possible. Addresses to the doctor concerning locks, disturbances of a menstrual cycle, sexual dysfunctions are possible, occasionally arthralgias, muscular pains and spasms can disturb patients. In the presence of significant increase in a thyroid gland patients pay attention to change of a shape of a neck.
At an explicit hypothyroidism patients are slowed down, apathetic, the speech and gestures slow, the deep voice, memory and intelligence are quite often lowered. Skin is dry, cold, a bowl pale, sometimes yellowish, it can be shelled that is especially noticeable on elbows. The yellowish or carrot shade of skin at patients contacts accumulation of carotene which exchange is broken at a hypothyroidism. Because of existence of dense hypostasis skin does not gather in folds, over - and subclavial hollows, inguinal folds look smoothed. The person odutlovato with rough lines, eyelids edematous, the nose, lips, language are thickened. Hair are dim, pilosis on a body scanty, loss of an outside third of eyebrows (a symptom of Hertoga), perhaps partial baldness is often noted. Nails dry and fragile.
From cardiovascular system bradycardia, expansion of borders and dullness of cardiac sounds is defined. Accumulation of liquid in a pericardium cavity is sometimes noted, exudate is rich with albumine and mucopolysaccharides. Due to the disturbance of sokratitelny ability of a myocardium and a pericardis development of heart failure is possible. Arterial pressure is variable, characteristic decrease systolic with the normal or increased diastolic pressure. The hypothyroidism contributes to development of atherosclerosis of coronary vessels, however stenocardia and myocardial infarctions are observed infrequently. Usually pains of anginal character develop with begun replacement therapy that complicates selection of an adequate dose and demands care from the doctor. Accumulation of exudate in a pleural cavity, bowl bilateral, ascites can meet.
The passage on a digestive tract is slowed down, locks are characteristic. Cases of a full atony of intestines with the advent of symptoms of colic impassability are described. In some cases there is a combination to autoimmune gastritis that is followed by development of a mucosal atrophy of a stomach and an achlorhydria.
From the central nervous system delay of cognitive functions, loss of an initiative, memory disturbance, drowsiness and the slow speech is noted. Syncopal states are possible. In some cases there is a night blindness connected with disturbances of an exchange of carotene and an ataxy, as a rule, of a cerebellar origin.
Tendon jerks are slowed down, especially in a relaxation phase. Disturbances of sensitivity and paresthesia in fingers of hands are connected with a tunnel syndrome which arises because of a prelum of a median nerve a myxedema in the carpal channel. Occasionally the inflammatory damage of muscles as a polymiositis which is shown their tension, consolidation, morbidity develops. The thyroid gland is not palpated in case of its reduction, an atrophy, fibrous changes, at an autoimmune thyroiditis it can look increased and condensed.
Methods of treatment of a hypothyroidism
The main method of treatment is replacement therapy by left thyroxine in a dose of 2,0 — 2,5 mkg/(kg-days) at young patients, patients of middle age have 1.5-2,0 mkg/(kg-days) and elderly.
The dose at elderly and sick middle age should be increased gradually, since 12,5-25 mkg/days as fast recovery of an euthyroidism can provoke destabilization of a current of an ischemic heart disease, cause fibrillation of auricles. Increase in a dose is carried out with internaly to 2 — 3 weeks to supporting a dose increase within 1-2 months, are guided on pulse rate, arterial pressure, an ECG and level of cholesterol. Adequacy of a dose is confirmed by research of level of thyritropic hormones. Average maintenance doses make 100 — 150 mkg a day.
The subclinical hypothyroidism demands obligatory purpose of left thyroxine in a dose of 1,5 — 2,0 mkg / kgsut) at increase of the TTG level in three and more times, in other cases the issue is resolved individually. In particular, such appointment is recommended to the pregnant women sick with a heavy dislipidemiya, at detection of a diagnostic caption of anti-thyroid antibodies, existence in the anamnesis of a hypothyroidism or hereditary burdeness on this disease.
In case of a hypothyroid coma left thyroxine is entered intravenously once in a dose of 500 mkg/h, further on 100 mkg/days. At suspicion on a secondary hypothyroidism for prevention of adrenal insufficiency treatment everyone four begin with intravenous administration of a hydrocortisone of a gemisuktsinat in a dose 50 — 100 mg, with the subsequent intramuscular introduction on 100 mg — six hours. Hold symptomatic events, gradual warming.