Hypothyroidism – the disease caused by decrease in function of a thyroid gland and insufficiency of production of hormones by it. It is shown by delay of all processes happening in an organism: weakness, drowsiness, increase in weight, sluggishness of thinking and the speech, a chill, hypotonia, at women - violations of a menstrual cycle. In severe forms the miksedema at adults and cretinism (weak-mindedness) at children develops. Complications of a disease are the gipotireoidny coma, damage of heart and vessels: bradycardia, atherosclerosis of coronary vessels, IBS. Treatment of patients with a hypothyroidism is carried out by artificially synthesized tireoidny hormone.
Hypothyroidism - the most common form of functional violations of a thyroid gland developing owing to long resistant deficiency of hormones of a thyroid gland or decrease in their biological effect at the cellular level. The hypothyroidism can not come to light long time. It is connected with the gradual, imperceptible beginning of process, satisfactory health of patients in easy and moderate degree of a disease erased by the symptoms regarded as overfatigue, a depression, pregnancy. Prevalence of a hypothyroidism makes about 1%, among women of reproductive age there are 2%, at advanced age increases up to 10%.
The lack of hormones of a thyroid gland causes system changes in work of an organism. Tireoidny hormones regulate power exchange in cages of bodies, and their deficiency is shown in decrease in consumption by oxygen fabrics, reduction of power consumption and processing of power substrata. At a hypothyroidism synthesis of various volatile cellular enzymes necessary for normal cell activity is broken. In case of the started hypothyroidism there is mutsinozny (mucous) hypostasis - a miksedema, the most expressed in connecting fabric. The miksedema as a result of an excess congestion in fabrics of glikozaminoglikan which, having the increased hydrophily, detain water develops.
Classification and reasons of a hypothyroidism
The hypothyroidism can be acquired and congenital (it is diagnosed right after the birth and can have any genesis). The most widespread is the acquired hypothyroidism (more than 99% of cases). Are the main reasons for the acquired hypothyroidism:
- chronic autoimmune tireoidit (direct damage of a parenchyma of a thyroid gland from own immune system). Leads to a hypothyroidism years and decades later after the emergence.
- yatrogenny hypothyroidism (during partial or full removal of a thyroid gland or after treatment by radioactive iodine).
The above-named reasons cause most often a resistant irreversible hypothyroidism.
- treatment of a diffusion toxic craw (reception of tireostatik);
- acute shortage of iodine in food, water. The easy and moderate lack of iodine at adults does not lead to a hypothyroidism. At pregnant women and newborns easy and moderate yododefitsit causes tranzitorny violations of synthesis of tireoidny hormones. In case of a tranzitorny hypothyroidism dysfunction of a thyroid gland can disappear in the course of the natural course of a disease or after disappearance of the factor which caused it.
The congenital hypothyroidism develops as a result of congenital structural violations of a thyroid gland or - hypophysial system, defect of synthesis of tireoidny hormones and various exogenous influences in the pre-natal period (application of medicines, existence of maternal antibodies to a thyroid gland at autoimmune pathology). Maternal tireoidny hormones, getting through a placenta, compensate control of pre-natal development of a fruit which has a pathology of a thyroid gland. After the birth the level of maternal hormones in blood of the newborn falls. Deficiency of tireoidny hormones causes an irreversible underdevelopment of TsNS of the child (in particular, a cerebral cortex) that is shown by intellectual backwardness in various degree, up to cretinism, violation development of a skeleton and other bodies.
Depending on the level of the happening violations allocate a hypothyroidism:
- primary – arises owing to pathology of the most thyroid gland and is characterized by increase in the TTG level (tireotropny hormone);
- secondary – is connected with damage of a hypophysis, T4 and TTG have low levels;
- tertiary – develops at dysfunction of a hypothalamus.
Primary hypothyroidism develops as a result of inflammatory processes, an aplaziya or a hypoplasia of a thyroid gland, hereditary defects of biosynthesis of tireoidny hormones, a subtotal or total tireoidektomiya, insufficient receipt in an iodine organism. In some cases the reason of primary hypothyroidism remains not clear – in this case the hypothyroidism is considered idiopathic.
Seldom observed secondary and tertiary hypothyroidism can be caused by various damages of gipotalamo-hypophysial system reducing control of activity of a thyroid gland (a tumor, surgery, radiation, a trauma, hemorrhage). The hypothyroidism caused by fabric resistance to tireoidny hormones or violation of their transport is independently allocated peripheral (fabric, transport).
Clinical features of manifestation of a hypothyroidism are:
- lack of the specific signs characteristic only of hypothyroidism;
- symptomatology similar to displays of other chronic somatic and mental diseases;
- lack of dependence between shortage level of hormones of a thyroid gland and degree of expressiveness of clinical symptoms: manifestations can be absent in a clinical phase or to be strongly expressed already in a phase of a subclinical hypothyroidism.
Clinical manifestations of a hypothyroidism depend on its reason, age of the patient, and also speed of increase of deficiency of tireoidny hormones. The hypothyroidism symptomatology in general is characterized by polysystemacity though at each certain patient complaints and concerns from any one system of bodies prevail that quite often prevents to make the correct diagnosis. The moderate hypothyroidism can not be shown by any signs.
At a resistant and long hypothyroidism at the patient characteristic appearance - an edematous, bloated face, with a yellowish shade is observed, swell a century, extremities, the liquids connected with a delay in connecting fabric. The burning sensation, prickings, muscular pains, constraint and weakness in hands disturb. Dryness of integuments, fragility and dimness of hair, their poredeniye and the strengthened loss are noted. Patients with a hypothyroidism are in a condition of apathy, block. Delay of the speech is characteristic of a severe form of a disease (as though, "language is braided"). There are changes of a voice (to low, hoarse) and decrease in hearing because of hypostasis of a throat, language and a middle ear.
At patients some increase in weight, a hypothermia, a constant chill is noted that speaks about decrease in level of exchange processes. Violations from nervous system are shown by a memory impairment and attention, decrease in intelligence, informative activity, interest in life. There are complaints to weakness, fatigue, frustration of a dream (drowsiness in the afternoon, falling asleep difficulty in the evening, sleeplessness). The general state is shown by the suppressed mood, melancholy, a depression. Psychological violations at children are more senior than 3 years and at adults are reversible and completely take place at purpose of replacement therapy. At a congenital hypothyroidism lack of replacement therapy conducts to irreversible consequences for nervous system and an organism in general.
Changes in cardiovascular system are noted: bradycardia, diastolic arterial hypertension of an easy form and formation of an exudate in a cavity of a pericardium (perikardit). There are frequent, then constant headaches, cholesterol level in blood increases, anemia develops. From digestive organs decrease in production of enzymes, deterioration in appetite, locks, nausea, a meteorizm is observed, dyskinesia of biliary tract, a gepatomegaliya can develop.
At women against the background of a hypothyroidism violations of reproductive system develop that is connected with failure of a menstrual cycle (, dysfunctional uterine bleedings), development of mastopathy. Pronounced deficiency of tireoidny hormones threatens with infertility, less obvious hypothyroidism at some women does not interfere with pregnancy, but threatens it with high risk of a spontaneous abortion or the child's birth with neurologic violations. Both men, and at women have a decrease in sexual desire.
Clinical manifestations of a congenital hypothyroidism cannot often help with its early diagnostics. Carry the blown-up stomach, umbilical hernia, hypotonia of muscles, big language, increase in a back fontanel and thyroid gland, a deep voice to early symptoms. If treatment in due time is not begun, then on 3-4 month of life swallowing difficulty, a loss of appetite, a small increase of weight, a meteorizm, locks, pallor and dryness of skin, a hypothermia, muscular weakness develop. At the age of 5-6 months the delay of psychomotor and physical development of the child is shown, growth disproportion is observed: late closing of fontanels, a wide nose bridge, increase in distance between pair bodies - a gipertelorizm (between inner edges of eye-sockets, chest nipples).
Complication of a congenital hypothyroidism is violation of activity of TsNS and development in the child mental retardation (intellectual backwardness), and sometimes its extreme degree – cretinism. The child lags behind in growth, sexual development, is subject to frequent infectious diseases with a long chronic current. The independent chair at it is complicated or impossible. The hypothyroidism at pregnancy is shown in various anomalies of development of a fruit (heart diseases, pathology of development of internals), the child's birth with functional insufficiency of a thyroid gland.
The heaviest, but seldom found hypothyroidism complication, - a gipotireoidny (miksedematozny) coma. Usually it arises at patients of advanced age with is long the proceeding, not lecheny hypothyroidism, serious associated diseases, having the low social status or in the absence of leaving. Development of a gipotireoidny coma is promoted by infectious diseases, injuries, overcooling, administration of drugs, oppressing activity of TsNS. Serve as manifestations of a gipotireoidny coma: the progressing braking of TsNS, confusion of consciousness, low indicators of body temperature, emergence of short wind, decrease in heart rate and arterial pressure, a sharp delay of urine, face edemas, hands and a body, intestinal impassability.
Liquid congestion in the field of a pericardium and a pleural cavity sharply break warm activity and breath. Substantial increase of level of cholesterol in blood provokes early development of IBS, a myocardial infarction, atherosclerosis of vessels of a brain, an ischemic stroke.
Men and women with a hypothyroidism can have infertility, they broke sexual function. At a hypothyroidism there are serious violations of immunity which are shown by often arising infections, progressing of autoimmune processes in an organism, development of oncological diseases.
Diagnostics of a hypothyroidism
For diagnosis of a hypothyroidism by the doctor-endocrinologist the fact of decrease in function of a thyroid gland on the basis of survey of the patient, his complaints, and results of laboratory researches is established:
- determination of level of a tiroksin - T4 and a triyodtironina – T3 (tireoidny hormones) and level of tireotropny hormone - TTG (hypophysis hormone) in blood. At a hypothyroidism the lowered content of tireoidny hormones in blood is noted, the maintenance of TTG can be both is increased, and lowered;
- autoantitet determination of level to a thyroid gland (AT-TG, AT-TPO).
- biochemical blood test (at a hypothyroidism the level of cholesterol and other lipids increases);
- Ultrasonography of a thyroid gland (for determination of its sizes and structure);
- stsintigrafiya of a thyroid gland or tonkoigolny biopsy.
Diagnostics of a congenital hypothyroidism is based on neonatal screening (determination of the TTG level for 4-5 day of life of the newborn).
Treatment of a hypothyroidism
Thanks to the achievements of pharmaceutical industry allowing to synthesize artificially tireoidny hormone, the modern endocrinology has an effective way of treatment of a hypothyroidism. Therapy is carried out by replacement of the tireoidny hormones lacking in an organism with their synthetic analog - levotiroksiny (L-tiroksinom).
The manifest (clinical) hypothyroidism demands purpose of replacement therapy irrespective of age of the patient and the accompanying pathology. The option of an initiation of treatment, an initial dose of medicine and speed of its increase is individually appointed. At a latent (subclinical) hypothyroidism the absolute indication for performing replacement therapy is its diagnosing at the pregnant woman or pregnancy planning in the nearest future.
In most cases normalization of the general condition of the patient with a hypothyroidism begins in the first week of the beginning of reception of medicine. Total disappearance of clinical symptoms happens usually within several months. At elderly people and the weakened patients reaction to medicine develops more slowly. To patients with cardiovascular diseases, it is required to select especially carefully a medicine dose (excess reception of L-tiroksina increases risk of stenocardia, vibrating arrhythmia).
In case of the hypothyroidism which resulted from removal of a thyroid gland or radiation therapy reception of synthetic hormones during all life is shown. Lifelong treatment of a hypothyroidism is also necessary against the background of an autoimmune tireoidit (Hashimoto's disease). In the course of treatment the patient needs to visit regularly the doctor for correction of a dose of medicine, to control the TTG level in blood.
If the hypothyroidism arises against the background of other diseases, normalization of function of a thyroid gland most often happens in the course of treatment of the main pathology. Symptoms of the hypothyroidism caused by reception of some drugs are eliminated after cancellation of these medicines. If the hypothyroidism reason – the lack of the use of iodine with food, to the patient is appointed by iodinated medicines, consumption of iodinated salt, seafood. Treatment of a gipotireoidny coma is carried out in intensive care units and resuscitation with purpose of intravenous administrations of high doses of tireoidny hormones and glucocorticosteroids, correction of a condition of a hypoglycemia, haemo dynamic and electrolytic violations.
Forecast and prevention of a hypothyroidism
The forecast at a congenital hypothyroidism depends on timeliness of the begun replacement therapy. At early identification and in due time begun replaceable treatment of a hypothyroidism at newborns (1 – 2 week of life) development of TsNS practically does not suffer and meets standard. At late compensated congenital hypothyroidism pathology of TsNS of the child (mental retardation) develops, formation of a skeleton and other internals is broken.
Quality of life of the patients with a hypothyroidism accepting the compensating treatment usually does not decrease (there are no restrictions, except for need of daily reception of L-tiroksina). The lethality at development of a gipotireoidny (miksedematozny) coma makes about 80%.
The prevention of development of a hypothyroidism consists in good nutrition with sufficient intake of iodine and is directed to its early diagnostics and in due time begun replacement therapy.