Hyperthyroidism (thyrotoxicosis) is a clinical syndrome caused by an increase in the hormonal activity of the thyroid gland and characterized by excessive production of thyroid hormones – T3 (triiodothyronine) and T4 (thyroxine). Oversaturation of the blood with thyroid hormones causes acceleration of all metabolic processes in the body (the so-called “metabolic fire”). This condition is the opposite of hypothyroidism, in which due to a decrease in the level of thyroid hormones, the metabolic processes slow down. If hyperthyroidism is suspected, a study of the level of thyroid hormones and TSH, ultrasound, scintigraphy, if necessary, a biopsy is performed. The disease is the opposite of hypothyroidism, in which due to a decrease in the level of thyroid hormones, the metabolic processes slow down. Hyperthyroidism is mainly diagnosed among young women.
Causes
Usually hyperthyroidism develops as a result of other thyroid pathologies caused by both disorders in the gland itself and in its regulation: in 70-80% of cases, hyperthyroidism develops due to diffuse toxic goiter (Graves’ disease, Basedova disease) – a uniform increase in the thyroid gland. This is an autoimmune disorder in which antibodies against pituitary TSH receptors are produced, contributing to the constant stimulation of the thyroid gland, its increase and persistent excess production of thyroid hormones.
With viral inflammation of the thyroid gland (subacute thyroiditis) or Hashimoto’s autoimmune thyroiditis, the destruction of thyroid follicular cells develops and an excess of thyroid hormones enters the blood. In this case, hyperthyroidism is temporary and mild, lasting several weeks or months. Local seals in the thyroid gland with nodular goiter further increase the functional activity of its cells and the secretion of thyroid hormones.
The presence of TSH-secreting tumors of the pituitary gland, as well as toxic thyroid adenoma (a tumor that produces thyroid hormones autonomously, regardless of pituitary control) or ovarian struma (a tumor consisting of thyroid cells and secreting thyroid hormones) leads to the development of hyperthyroidism. The condition of hyperthyroidism can develop with uncontrolled intake of a large amount of synthetic thyroid hormones or tissue immunity of the pituitary gland to thyroid hormones. Women, persons with a burdened hereditary history, the presence of autoimmune pathology are predisposed to the development of hyperthyroidism.
Classification
Depending on the level of the disorder, there are primary hyperthyroidism (caused by thyroid pathology), secondary (caused by pituitary pathology), tertiary (caused by hypothalamus pathology). There are several forms of primary hyperthyroidism:
- subclinical (T4 level is normal, TSH is lowered, the course is asymptomatic);
- manifest or explicit (the level of T4 is increased, TSH is significantly reduced, characteristic symptoms are observed);
- complicated (atrial fibrillation, cardiac or adrenal insufficiency, dystrophy of parenchymal organs, psychoses, severe weight deficiency, etc.).
Hyperthyroidism symptoms
The manifestations of hyperthyroidism in various thyroid lesions are similar, although each pathology, accompanied by a high level of thyroid hormones, has its own characteristics. Symptoms depend on the duration and severity of the disease, on the degree of damage to a particular system, organ or tissue.
With hyperthyroidism, pronounced disorders of the central nervous system and mental activity develop: nervousness and increased excitability, emotional imbalance (irritability and tearfulness), a sense of fear and anxiety, increased mental processes and rapid speech, impaired concentration of thoughts, their sequence, insomnia, small-scale tremor.
Cardiovascular disorders in hyperthyroidism are characterized by a violation of the heart rhythm (persistent sinus tachycardia, poorly treatable; atrial flicker and flutter), an increase in systolic (upper) and a decrease in diastolic (lower) blood pressure, increased pulse rate, an increase in linear and volumetric blood flow velocity, the development of heart failure.
Ophthalmological disorders (Graves’ ophthalmopathy) with hyperthyroidism are found in more than 45% of patients. It is manifested by an increase in the eye slit, displacement (protrusion) of the eyeball forward (exophthalmos) and restriction of its mobility, rare blinking, double vision of objects, swelling of the eyelids. There is dryness, corneal erosion, there is pain in the eyes, lacrimation, blindness may develop as a result of compression and dystrophic changes of the optic nerve.
Hyperthyroidism is characterized by changes in metabolism and acceleration of basal metabolism: weight loss with increased appetite, the development of thyrogenic diabetes, increased heat production (sweating, fever, heat intolerance), adrenal insufficiency as a result of the rapid breakdown of cortisol under the influence of thyroid hormones. With hyperthyroidism, skin changes occur – it becomes thin, warm and moist, hair – they thin and turn gray early, nails, swelling of the soft tissues of the lower leg develops.
As a result of edema and congestion in the lungs, shortness of breath and a decrease in the vital capacity of the lungs develop. Gastric disorders are observed: increased appetite, digestive disorders and bile formation, unstable stools (frequent diarrhea), attacks of abdominal pain, enlarged liver (in severe cases – jaundice). In elderly patients, there may be a decrease in appetite up to anorexia.
With hyperthyroidism, signs of thyrotoxic myopathy are observed: muscle hypotrophy, muscle fatigue, constant weakness and trembling in the body, limbs, the development of osteoporosis, motor activity disorders. Patients have difficulty walking for a long time, climbing stairs, carrying heavy loads. Sometimes reversible “thyrotoxic muscle paralysis” develops.
Violation of water metabolism is manifested by intense thirst, frequent and copious urination (polyuria). The disorder of the functions of the genital sphere in hyperthyroidism develops as a result of a violation of the secretion of male and female gonadotropins and can cause infertility. Women have menstrual irregularities (irregularity and soreness, poor discharge), general weakness, headache and fainting; men have gynecomastia and impotence.
Complications
With an unfavorable course of hyperthyroidism, a thyrotoxic crisis may develop. Infectious diseases, stress, heavy physical activity can provoke it. The crisis is manifested by a sharp exacerbation of all the symptoms of hyperthyroidism: fever, sharp tachycardia, signs of heart failure, delirium, progression of the crisis to a comatose state and death. An “apathetic” variant of the crisis is possible – apathy, complete indifference, cachexia. Thyrotoxic crisis occurs only in women.
Diagnostics
Hyperthyroidism is diagnosed by characteristic clinical manifestations (patient’s appearance and complaints), as well as research results. In hyperthyroidism, it is informative to determine the content of TSH hormones in the blood (the content is reduced), T 3 and T 4 (the content is increased).
With ultrasound of the thyroid gland, its size and the presence of nodular formations in it are determined, with the help of computed tomography, the place of formation of nodes is specified. Conducting an ECG records the presence of abnormalities in the work of the cardiovascular system. Radioisotope scintigraphy of the thyroid gland is performed to assess the functional activity of the gland, to determine nodular formations. If necessary, a thyroid node biopsy is performed.
Hyperthyroidism treatment
Modern endocrinology has several methods of treating hyperthyroidism, which can be used in isolation or in combination with each other. Such methods include:
- Conservative (drug) therapy.
- Surgical removal of part or all of the thyroid gland.
- Radioiode therapy.
It is definitely impossible to determine the best method that would be suitable for absolutely all patients with hyperthyroidism. The choice of a treatment method that is optimally suitable for a particular hyperthyroid patient is carried out by an endocrinologist taking into account many factors: the patient’s age, the disease that caused hyperthyroidism and its severity, allergy to medications, the presence of concomitant diseases, individual characteristics of the body.
Conservative treatment
Drug treatment of hyperthyroidism is aimed at suppressing the secretory activity of the thyroid gland and reducing the production of excess thyroid hormone production. Thyrostatic (antithyroid) drugs are used: methimazole or propylthiouracil, which make it difficult to accumulate iodine necessary for the secretion of hormones in the thyroid gland.
Non-drug methods play an important role in the therapy and recovery of patients with hyperthyroidism: diet therapy, hydrotherapy. Patients with hyperthyroidism are recommended sanatorium treatment with an emphasis on cardiovascular diseases (once every six months).
The diet should include a sufficient content of proteins, fats and carbohydrates, vitamins and mineral salts, products that excite the central nervous system (coffee, strong tea, chocolate, spices) are subject to restriction.
Surgical treatment
Before making a responsible decision about a surgical operation, all alternative methods of treatment are discussed with the patient, as well as the type and scope of possible surgical intervention. The operation is indicated for some patients with hyperthyroidism and consists in removing part of the thyroid gland. Indications for surgery are a single node or an overgrowth of a separate area (hillock) of the thyroid gland with increased secretion. The part of the thyroid gland remaining after the operation performs a normal function. With the removal of most of the organ (subtotal resection), hypothyroidism may develop, and the patient needs to receive replacement therapy throughout his life. After removal of a significant portion of the thyroid gland, the risk of recurrence of thyrotoxicosis is significantly reduced.
Treatment with radioactive iodine
Radioiodotherapy (treatment with radioactive iodine) consists in taking a capsule or an aqueous solution of radioactive iodine by the patient. The drug is taken once, has no taste and smell. Once in the blood, radioiodine penetrates into thyroid cells with hyperfunction, accumulates in them and destroys them within a few weeks. As a result, the size of the thyroid gland decreases, the secretion of thyroid hormones and their level in the blood decrease. Treatment with radioactive iodine is prescribed simultaneously with medication. Complete recovery with this method of treatment does not occur, and patients sometimes have hyperthyroidism, but less pronounced: in this case, it may be necessary to repeat the course.
More often, after treatment with radioactive iodine, a state of hypothyroidism is observed (after a few months or years), which is compensated by replacement therapy (lifelong intake of thyroid hormones).
Other methods of treatment
In the treatment of hyperthyroidism, beta-blockers can be used to block the effect of thyroid hormones on the body. The patient may feel better within a few hours, despite the excessive level of thyroid hormones in the blood. Beta – blockers include drugs: atenolol, metoprolol, nadolol, propranolol, which have a long-term effect. With the exception of hyperthyroidism caused by thyroiditis, these medications cannot be used as an exceptional treatment method. beta – blockers can be used in combination with other methods of treating thyroid diseases.
Prognosis and prevention
Patients with hyperthyroidism must be under the supervision of an endocrinologist. Timely and adequately selected treatment allows you to restore well-being faster and prevent the development of complications. It is necessary to start treatment immediately after diagnosis and categorically not to self-medicate. Prevention of the development of hyperthyroidism consists in proper nutrition, timely treatment of existing thyroid pathology.