Hypothyroidism - causes, symptoms, treatment, consequences

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Hypothyroidism - causes, symptoms, treatment, consequences
Hypothyroidism - causes, symptoms, treatment, consequences
Anonim

What is hypothyroidism?

Hypothyroidism
Hypothyroidism

Hypothyroidism is a process that occurs due to a lack of thyroid hormones in the thyroid gland. This disease occurs in about one in a thousand men and nineteen out of a thousand women. Often there are cases when the disease is difficult to detect, and for a long time. The reason for the diagnostic difficulties is that the disease occurs and develops slowly, and it is characterized by signs that make it difficult to recognize hypothyroidism. Usually the symptoms are mistaken for simple overwork, in women - for pregnancy or something else.

Due to the occurrence and spread of this disease, the main metabolic processes in the body are inhibited, since thyroid hormones are responsible for energy metabolism.

Hypothyroidism:

  • It rarely becomes a separate disease associated with the pathology of the thyroid gland only;
  • Not an independent disease and should not be the only diagnosis (except in rare cases);
  • Becomes a complication or natural consequence of any pathology of the thyroid gland with the exception of hyperthyroidism;
  • It is based on functional disorders in the form of insufficient production of thyroid hormones (triiodothyronine, tetraiodothyronine (thyroxine), calcitonin), their inferiority or premature inactivation in tissues;
  • Causes a violation of the general hormonal background and metabolic processes in the body.

Each of these points requires a little clarification. After all, the prevalence of this pathology is very wide, which causes a high interest among the population in relation to expanding knowledge about it. Another name for extreme hypothyroidism is myxedema.

Hypothyroidism is rarely a single disease or a single diagnosis

If we consider this statement from a pathogenetic point of view, then it is 100% true. The only exceptions are those cases when it is impossible to establish the primary cause of hypothyroidism, or clinical signs of hypothyroidism are recorded against the background of a normal amount of thyroid hormones. Then this disease may be the only diagnosis that sounds like “idiopathic hypothyroidism.”

In all other cases, there must be a primary disease that caused a violation of the functional abilities of the thyroid gland in relation to the synthesis of thyroid hormones. A long course of hypothyroidism will certainly cause severe disorders in the body, which will be displayed as a layering of other diseases, in which it will become an unfavorable background for their further progression.

Hypothyroidism is a functional pathology of the thyroid gland affecting the whole body

Hypothyroidism is based not on organic changes in the tissues of the thyroid gland and their structural restructuring, but on a violation of the ability to synthesize the corresponding hormones (thyroxine, triiodothyronine, calcitonin).

The consequences that arise in this case cause other functional and even organo-anatomical disorders in almost all organs and tissues. After all, thyroid hormones are involved in important biochemical reactions that regulate the metabolic processes of protein and mineral metabolism and the synthesis of steroid and sex hormones, the growth and development of the musculoskeletal system, the functional abilities of the heart and brain. Hypothyroidism causes not only difficulty in the functioning of these organs, but also a violation of their anatomical structure.

Despite the fact that hypothyroidism is a functional disorder, manifested by dysfunction of the thyroid gland, its consequences and complications are of an organic nature. The disease causes a violation of the normal structure of target organs that are dependent on thyroid hormones. At the same time, the thyroid gland itself, as a rule, also changes its structure, but the changes are not due to hypothyroidism, but to the disease that caused it!

Hypothyroidism is a syndrome of general hormonal imbalance

Hypothyroidism
Hypothyroidism

The endocrine system of the human body functions like a closed circuit. The loss of one of its links will necessarily slow down the work of the others. This is what happens with hypothyroidism.

After all, the hormones thyroxine, triiodothyronine and calcitonin interact with:

  • Pituitary hormones that regulate the functioning of the thyroid gland - their lack stimulates the production of thyroid-stimulating hormone, which provokes the growth of the thyroid gland in diffuse volume, in the form of nodes or cancerous tumors;
  • Other tropic hormones of the hypothalamic-pituitary system - against the background of a decrease in thyroid and increased activity of thyroid-stimulating hormone, an increase in the amount of prolactin is possible. Such changes lead to permanent galactorrhea and changes in the mammary glands, and additionally disrupt the synthesis of sex hormones by the ovaries;
  • Steroid hormones of the gonads and adrenal glands - the activity of their synthesis is significantly reduced, since thyroid hormones cannot provide adequate activity of protein metabolism in the liver. As a result, there is a lack of building material for steroids, which for the most part consist of protein, and hormonal insufficiency of the testicles, ovaries and adrenal glands;
  • Parathyroid glands - a lack of calcitonin causes a violation of calcium metabolism, which is the result of the leaching of calcium ions from the bone tissue from excessive parathyroid hormone activity.

When can hypothyroidism be an independent disease?

Those clinical variants of hypothyroidism, when the thyroid gland synthesizes a sufficient amount of hormones and their concentration in the blood is normal, are referred to as paradoxical types of the disease. This is truly incredible and seemingly impossible. After all, if thyroid hormones are produced normally, then where can the symptoms of hypothyroidism come from? It turns out that this happens too.

The main mechanism of this kind of conditions is the abnormal structure of thyroid hormones or their rapid destruction in the blood. Various autoimmune conditions are capable of triggering such pathological processes against the background of systemic diseases or after suffering a severe pathology (infections, injuries, pancreatic necrosis, burns). Despite a sufficient amount of the hormone circulating in the plasma, it is unable to fully fulfill its purpose, as it is inactivated by the person's own immune cells. In the same way, clinical hypothyroidism also occurs when thyroxine receptors in its target organs are destroyed.

Symptoms of Hypothyroidism

Symptoms of hypothyroidism
Symptoms of hypothyroidism

The clinical picture of hypothyroidism can be represented by symptoms of the underlying disease of the thyroid gland, which caused its dysfunction, and direct signs of hypothyroidism.

In short, the main symptoms of hypothyroidism are:

  • menstrual irregularities in women;
  • dramatic weight gain, albeit slight. It is caused by a drop in metabolic rate, but appetite is reduced, which prevents a significant increase in body weight;
  • feeling nausea, bloating, constipation. Face and limbs may swell;
    • the hair of a sick person becomes dry and brittle, begins to fall out strongly;
    • scalp may become yellowish;
    • hearing impairment occurs and the voice changes (this symptom is typical for especially acute forms, and occurs due to swelling of the tongue, larynx and middle ear);
    • fatigue, weakness; thinking and speech become slower; a feeling of chills occurs, which is caused by a slow metabolism.

    Details of all the symptoms are discussed in the table:

    Affected organ system in hypothyroidism

    Symptoms of disease

    Skin and subcutaneous tissue
    • Pale skin combined with a slight icteric tint;
    • Severe dry skin combined with peeling;
    • Violation of the structure and growth of nails and hair;
    • Puffy face;
    • Dense swelling of the upper and lower extremities. After pressing on the edematous tissues, there is no trace left;
    • Decrease in body temperature;
    • Weight gain and obesity;
    Musculoskeletal system
    • Severe general weakness and impotence;
    • Decreased muscle tone and strength;
    • Muscle pains and cramps of individual muscle groups;
    • Density and disproportionate thickening of the muscles of the upper half of the body;
    • Inability to quickly relax muscles after exercise;
    • Stiff movement and slowness.
    Heart and blood vessels
    • Bradycardia with a sharp decrease in heart rate;
    • Pain in the chest and behind the sternum;
    • Irregular heart rhythm in the form of extrasystole;
    • Enlargement of the heart in size (cardiomegaly);
    • Deafness of heart sounds during auscultation;
    • Appearance of signs of pericarditis in the form of effusion in the pericardial cavity;
    • Lower blood pressure.
    Nervous system
    • Inhibition and apathy;
    • Numbness of limbs;
    • Decreased reflexes;
    • Depressive and hallucinatory syndromes;
    • Decrease in memory and mental abilities, up to cretinism;
    • Hearing and visual acuity decrease.
    Endocrine disorders
    • Impaired adrenal function, manifested by an increase in the main symptoms of hypothyroidism;
    • Menstrual disorders;
    • Amenorrhoea (complete absence of menstruation);
    • Galactorrhea (excretion of milk from the mammary glands in the absence of breastfeeding);
    • Decreased libido;
    • Impotence and impotence.
    The defeat of the blood system
    • Decreased hemoglobin and iron deficiency anemia;
    • Megaloblastic anemia;
    • Leukopenia (very rare);
    • Decreased immunity;
    Digestion and kidneys
    • Atonic constipation;
    • Gastritis, accompanied by constant pain in the epigastrium;
    • Nausea and vomiting;
    • Indigestion and the presence of undigested food particles in the feces;
    • Decrease in the amount of daily urine.

    The main and one of the first symptoms of hypothyroidism are: skin lesions with severe dense swelling of soft tissues, combined with general weakness, arterial hypotension, bradycardia, mental and sexual disorders!

    Causes of hypothyroidism

    Hypothyroidism, as an endocrine disease, can occur due to direct damage to the thyroid gland and due to other pathologies associated with impaired functions and structure of the organs that regulate its work.

    The main causes of hypothyroidism and etiological classification are given in the form of a table.

    Etiological type of hypothyroidism

    Immediate causes and diseases

    Primary (it is based on damage to the thyroid gland, which leads to its functional inferiority)
    1. Innate factors:

      • Underdevelopment of the thyroid gland (hypo- and aplasia);
      • Hereditary fermentopathy with damage to thyroid enzymes involved in the synthesis of thyroid hormones;
    2. Factors of acquired origin:

      • Condition after removal of the thyroid gland (strumectomy);
      • Ionizing radiation during radiation therapy of tumor diseases, or natural origin in areas of man-made disasters associated with nuclear emissions;
      • Treatment with radioactive iodine preparations;
      • Thyroiditis (inflammatory processes of the thyroid gland) of microbial and autoimmune origin;
      • Iodine deficiency conditions and endemic goiter against their background;
      • Overdose of drugs that inhibit the synthesis of thyroid hormones and amiodarone;
      • Tumor lesion of the thyroid gland.
    Secondary (caused by decreased activity of the pituitary gland in relation to the ability to synthesize thyroid-stimulating hormone)
    • Ischemic damage to the pituitary gland in atherosclerosis of cerebral vessels or acute severe anemia due to bleeding;
    • Inflammation of intracranial structures in the pituitary region of the brain;
    • Tumor transformation of adenohypophyseal cells;
    • Pituitary damage due to autoimmune diseases;
    • Toxic effect of drugs on glandular pituitary cells (levodopa, parlodel).
    Tertiary (represented by damage to the hypothalamic nuclei)
    • Meningoencephalitis involving the hypothalamic zone;
    • Severe traumatic brain injury;
    • Intracerebral tumors;
    • Therapy with serotonin drugs.
    Peripheral (impaired action of existing thyroid hormones)
    • Autoimmune processes during which antibodies to thyroid hormones are formed;
    • Congenital or hereditary disorders of the structure of receptors in tissues through which thyroid hormones carry out their action;
    • Fermentopathy of the kidneys and liver, leading to impaired conversion of thyroxine to triiodothyronine;
    • Defects in transport proteins that transport hormones into organ cells.

    This disease can be very well camouflaged. The lack of thyroid hormones, especially in females, causes depression, a constant bad mood, and a feeling of incomprehensible sadness. In a sick person, intelligence can be hidden or openly reduced, attention and memory become poor, and cognitive function decreases. It becomes difficult for a person to fall asleep, insomnia begins, or, conversely, regularly sleeps.

    The longer an undetected and untreated disease has spread since its onset, the greater the likelihood of an intracranial hypertension syndrome. A person complains of regular pain in the head. The patient can live in peace, thinking that cervical (or some other) osteochondrosis is to blame. Suspicions are also caused by muscle pain in the arms, a feeling of weakness in them, tingling and goosebumps. Hypothyroidism is also taken for heart disease, as blood pressure and cholesterol levels in the patient’s blood rise.

    In the case of female hypothyroidism, mastopathy may develop, menstruation fails.

    Another sign of illness is swelling of certain parts of the body. Eyelids swell more often, other places - less often, but edema is still the main indicator of the presence of hypothyroidism. A repeated decrease in immunity in humans can have an impact on the appearance of the disease. And it can occur even with the smallest violation of the functioning of the thyroid gland. Another sign is anemia, which occurs because the thyroid gland is responsible for blood formation.

    Hypothyroidism in more than 95% of cases is primary and is caused by pathology of the thyroid gland. Therefore, when clinical manifestations of hypothyroidism are detected, this organ is examined first of all!

    Primary hypothyroidism

    Primary hypothyroidism
    Primary hypothyroidism

    Almost all cases of hypothyroidism are associated with a direct violation of the structure and functioning of the organ that is responsible for the synthesis of thyroid hormones. This organ is the thyroid gland. It is quite logical that the criteria for the degree of the pathological process in any organ are the severity of changes in its structure and the ability to perform the function that it is supposed to perform. With regard to primary hypothyroidism, the causal relationship is built in such a way that the thyroid gland, due to a violation of its structure, is not able to synthesize the hormones T4 and T3. This causes the clinical manifestations of hypothyroidism, which are superimposed on the symptoms of the underlying disease.

    The main diseases of the thyroid gland that can cause primary hypothyroidism include congenital diseases in the form of underdevelopment or complete absence of an organ, inflammatory changes (thyroiditis), cancerous tumors and a banal endemic goiter with insufficient intake of iodine. Complete or partial removal of the thyroid gland also causes hypothyroidism of varying severity.

    To conduct a differential diagnosis between all types of hypothyroidism and confirm the primary type will help:

    • Clinical findings - signs of thyroid involvement (enlargement, nodules, difficulty swallowing and sore throat) along with symptoms of hypothyroidism;
    • Data from ultrasound, MRI or radioisotope diagnostics, indicating the presence of a structural reorganization of the thyroid gland and a decrease in its functional abilities;
    • A blood test to determine plasma concentrations of thyroid hormones: T4, T3, TSH. In primary hypothyroidism, T3 and T4 levels are always low. TSH compensatory increases in order to increase the stimulation of the thyroid gland to produce hormones, or remains within the normal range.

    Secondary hypothyroidism

    Secondary hypothyroidism
    Secondary hypothyroidism

    Secondary hypothyroidism is a type of decrease in the functional abilities of the thyroid gland, which occurs not as a result of damage to its tissues, but due to a violation of the regulation of functional activity in relation to the production of hormones. The thyroid gland, like any organ of the endocrine system, depends on the regulatory glands. These are the pituitary and hypothalamus. Speaking of secondary hypothyroidism, they mean a violation of the activity of hypothalamic thyroid-stimulating hormone. It is either not produced by the pituitary gland, or acquires an abnormal structure. In any case, a situation arises in which an anatomically he althy and unchanged thyroid gland is not able to synthesize thyroxine.

    Various intracerebral pathological processes can cause damage to the glandular cells of the pituitary gland in the form of traumatic injuries, tumors, circulatory disorders in the cerebral arteries, and autoimmune destruction. With regard to clinical manifestations, secondary hypothyroidism differs from primary in that symptoms of damage to other endocrine glands, ovaries and adrenal glands, join the typical clinical picture. This causes more severe than with primary hypothyroidism, disorders of the muscular system and the heart, severe impairment of intellectual abilities, sexual disorders in the form of persistent amenorrhea and infertility, atrophy of the genital organs and mammary glands, excessive hair growth, sexual infantilism and electrolyte disorders.

    Confirm secondary hypothyroidism can help:

    • Absence of clinical and instrumental signs of thyroid damage with a clear clinical picture of hypothyroidism;
    • Data of X-ray examination of the skull in two projections with the study of the area of the Turkish saddle, where the pituitary gland is located;
    • Computed tomography and MRI of the head, which will help determine the presence or absence of objective causes that caused secondary hypothyroidism;
    • A blood test to determine plasma concentrations of specific thyroid and pituitary hormones. The diagnostic criteria for secondary hypothyroidism are a decrease in the level of T3, T4 and TSH.

    In some cases we have to talk about tertiary hypothyroidism. It is also not associated with diseases of the thyroid gland, but is due to a violation of the regulation of its activity. In this case, the pathogenetic chain will be even more complicated, since the work of not one, but two links of regulatory processes is disrupted. The nuclei of the hypothalamic part of the brain are affected, which are responsible for the synthesis of hormones that regulate the activity of hormone production by the pituitary gland. In the case of tertiary hypothyroidism, everything looks like this: the hypothalamus does not produce thyreoliberin - the pituitary gland does not produce TSH - the thyroid gland does not produce thyroid hormones.

    Consequences of hypothyroidism

    Consequences of hypothyroidism
    Consequences of hypothyroidism

    Hypothyroidism can be conditionally divided into clinical forms of moderate and severe. It all depends on the amount of thyroid hormones produced by the thyroid gland. If they are not present at all, the consequences will be simply catastrophic, and such hypothyroidism will acquire an extremely severe course. This form of hypothyroidism is called myxedema. With a partially preserved ability of the thyroid gland to produce hormones, the functioning of the body is disrupted, but such consequences are quite reversible and compatible with everyday life.

    Patients with hypothyroidism should be aware that the following consequences may occur without appropriate hormone replacement therapy.

    In children:

    • Lagging behind the child in mental and physical development, up to cretinism;
    • Delay in the appearance of secondary sexual characteristics, up to complete infantilism;
    • Heart problems;
    • A sharp decrease in the defenses of the immune system, which is manifested by frequent colds, severe exacerbations of chronic infections;
    • Severe weakness and inability of the child to bear physical activity.

    Adults:

    • Decrease in mental abilities, memory and intelligence;
    • Persistent heart problems;
    • Sustained reduction in blood pressure;
    • Long course of chronic diseases and infectious processes;
    • Disorders of the menstrual function;
    • Atrophy of the ovaries, vulva and mammary glands;
    • Sexual impotence, impotence and infertility;
    • Hypothyroid coma (a critical decrease in hormone levels, leading to severe metabolic disorders up to a critical drop in cardiac activity and the brain, accompanied by a persistent loss of consciousness).

    All the serious consequences of hypothyroidism can be avoided by careful attention to the existing problem in the early stages of its development. The sooner the diagnosis is detailed and the appropriate hormone replacement therapy is started, the fewer disorders will occur in the body!

    Hypothyroidism treatment

    The treatment process for hypothyroidism involves the impact on the main links of this disease and includes the following methods:

    Etiotropic therapy

    Involves treating the underlying disease or condition that caused hypothyroidism. Unfortunately, this kind of help is not always possible. Even when it is possible to act on the true cause of hypothyroidism, the effect is rare.

    In the complex of etiotropic therapy according to indications can be used:

    • Iodine preparations. Indicated for endemic goiter due to iodine deficiency in food and its insufficient intake;
    • Adequate treatment of inflammatory and other thyroid diseases that caused hypothyroidism;
    • X-ray therapy or other treatments for diseases of the hypothalamic-pituitary system;

    Pathogenetic and symptomatic therapy

    Assumes a slowdown in the progression of pathological changes in organs and tissues that occur against the background of the absence of thyroid hormones. This type of treatment can never be used as an independent, and always complements the basic treatment with hormonal drugs.

    Hormone Replacement Therapy

    This type of treatment is the only correct solution for hypothyroidism. Hormones should become basic. All other activities are supportive. The principle of hormone replacement therapy is simple: the artificial introduction of thyroid hormones into the body.

    From preparations containing thyroid hormones, thyroxine and triiodothyronine can be used. If earlier the second drug was used much more often, then modern endocrinologists have come to the conclusion that its use is inappropriate. T3 has a negative effect on the myocardium, aggravating heart damage against the background of hypothyroidism. The only situation where it can be more effective than thyroxine is a hypothyroid coma, in which intravenous administration of triiodothyronine has a fairly rapid therapeutic effect.

    As for T4 hormone replacement therapy, it involves the use of drugs containing levothyroxine (L-thyroxine).

    When prescribing thyroxin preparations, it is important to adhere to the following principles:

    1. Expected lifelong intake. The exception is cases of temporary primary hypothyroidism that occurs against the background of thyroid pathology and in the early postoperative period after removal of its part;
    2. Gradual dose selection, taking into account the severity of hormonal deficiency, the age of the patient, the duration of the disease. The following pattern can be traced: the longer and more pronounced untreated hypothyroidism, the higher the body's sensitivity to the action of hormonal drugs;
    3. Mandatory monitoring of the effectiveness oftreatment based on signs of clinical improvement and according to the hormonal spectrum of the blood (increased concentrations of T4, T3 and a decrease in TSH);
    4. Use of low dosages in patients with concomitant heart disease. The dose in these patients should be increased very slowly under ECG monitoring;
    5. The feasibility of a subsequent increase in dose is evaluated after the maximum possible manifestation of the effectiveness of the previous one (at least 4-6 weeks).

    The most effective treatment for hypothyroidism is L-thyroxine replacement therapy. Its dosage, frequency and mode of administration should be determined only by an endocrinologist under the control of the hormonal spectrum of blood and clinical data!

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