Thyroid hyperplasia is an enlargement of the entire gland or its parts, which may be accompanied by the formation of individual nodes. The causes of pathology are iodine deficiency, infectious and autoimmune processes, hereditary factors. The disease is manifested by a feeling of compression in the neck, deformation of its contours, signs of hormonal imbalance. To diagnose hyperplasia, ultrasound, CT or MRI of the thyroid gland, radioisotope scanning, hormone tests are performed. Treatment depends on the severity and cause of the disease: iodine preparations, thyrostatics, surgical intervention are prescribed.
Meaning
Thyroid hyperplasia is not an independent nosological form. This is one of the most frequent ultrasound symptoms in practical endocrinology, which accounts for up to 85% of pathological changes in the organ. With instrumental imaging, hyperplastic processes are detected in 5% of the population, but clinical symptoms do not always occur. Thyroid pathology is more common in women, which is associated with the important role of the autoimmune component in its development.
Causes
The main cause of thyroid hyperplasia is called insufficient iodine intake and the formation of endemic goiter. 35% of the US population has severe iodine deficiency, while the rest of the people suffer from mild micronutrient deficiency. Residents of mountainous regions are at the greatest risk. Other etiological factors of the disease:
- Autoimmune processes. The appearance of specific growth-stimulating factors (IgG) provokes an increase in the parenchyma of the organ. Such changes are observed in 84% of patients with nodular hyperplasia, less common in diffuse non-toxic goiter. Type 1 diabetes mellitus, diseases of the adrenal glands contribute to the enlargement of the gland.
- Infection. Hyperplasia occurs at the stage of thyrotoxicosis in subacute de Quervain thyroiditis caused by paramyxoviruses, herpesviruses, adenoviruses and other groups of viruses. Among patients with enlarged thyroid gland, 44% have foci of chronic infection, primarily tonsillitis.
- Genetic factors. Hyperplasia can occur as a congenital developmental anomaly, which is formed due to disorders of embryogenesis with spontaneous mutations. Pathology also acts as one of the components of Down and Klinefelter syndromes.
- Exogenous effects. The effect of cigarettes on the thyroid gland has been well studied – hyperplasia occurs 2 times more often in smokers than in a group of people without a bad habit. A negative contribution is made by increased radiation background, occupational hazards, living in megacities with poor ecology.
- Excess of goiterogens in the diet. Goiterogens are called goiter substances that worsen the absorption of iodine in the body and contribute to the development of goiter. These compounds are present in large quantities in all types of cabbage, spinach, soy, mustard.
Pathogenesis
The morphological basis of hyperplasia is an increase in the number of cells in the thyroid gland. The mechanism of its development depends on the etiological factor. With a lack of iodine, a combination of multidirectional processes is observed: stimulation of the organ with thyroid-stimulating hormone, which is produced against the background of a deficiency of a trace element, and the loss of the process of iodine autoregulation, which restrains hyperplastic processes.
Similar pathological changes are observed when the thyroid gland is exposed to goitre substances that are contained in food, medicines, tobacco smoke. Such compounds compete with iodine at the level of its capture or transformation in follicular cells, causing the phenomena of relative iodine deficiency. In the inflammatory process, organ enlargement is associated with infiltration by lymphocytes, plasma cells and histiocytes.
Classification
There is no single approach to the systematization of hyperplasia in clinical endocrinology. The most well-known classification according to WHO, which contains only 2 stages: palpable and visible enlargement of the thyroid gland. Ultrasound protocols are divided into 4 degrees, depending on the percentage increase in the volume of the thyroid gland. In American practice, a classification that includes 5 stages is widely used:
- Stage I. On external examination, there are no signs of hyperplasia, but during palpation it is possible to detect the isthmus of the thyroid gland.
- Stage II. The organ is not visible on visual inspection, both lobes and the isthmus between them are well defined on palpation.
- Stage III. The thyroid gland is enlarged so much that it can be detected by external examination — a symptom of a “thick neck”. At the same time, the thyroid lobes do not go beyond the boundaries of the nodding muscles.
- Stage IV. Progressive hyperplasia, which causes a significant and uneven enlargement of the gland, deformation of the contours of the neck.
- Stage V. The gigantic size of the thyroid gland, which is accompanied by violations of respiratory, swallowing and speech function.
Symptoms
The clinical picture of thyroid hyperplasia has two components: discomfort caused by compression of neighboring tissues, and systemic manifestations that are associated with changes in the level of thyroid hormones in the blood. In the initial stages of hyperplasia, when the patient has a state of euthyroidism, any symptoms are absent. During this period, it is possible to detect the problem only with ultrasound scanning performed as planned.
When hyperplasia reaches a significant degree, patients feel a feeling of compression and discomfort in the neck area. This is accompanied by a sore throat, hoarseness of the voice, rapid fatigue during speech loads. Gradually, the disease progresses, causing difficulty swallowing solid and liquid food, shortness of breath and a feeling of lack of air. Also, patients notice a visible increase in the anterior surface of the neck.
With a combination of hyperplasia and thyrotoxicosis, patients complain of increased sweating, intolerance to heat and stuffiness, trembling in their hands and palpitations. Such people have an increased appetite and thirst, but despite a high-calorie diet, they gradually lose weight. Psychoemotional reactions in the form of irritability, unmotivated aggression, inability to concentrate are characteristic.
Against the background of hyperplasia, a decrease in thyroid function is possible – hypothyroidism, which has the opposite clinical picture. Patients have swelling and weight gain, constantly depressed mood, chilliness and cold extremities. Many people suffer from dryness and peeling of the skin, chronic constipation, decreased sexual desire. Women have menstrual irregularities.
Complications
The outcome of most thyroid diseases that manifest hyperplasia is called hypothyroidism. This is a persistent decrease in the number and clinical effects of thyroid hormones, accompanied by severe disorders in all organ systems. Without treatment, there is a risk of decompensation of the condition and the development of hypothyroid (myxedematous) coma.
With the long-term existence of hyperplasia and violation of thyroid function, infertility, anemia, and a persistent decrease in intellectual abilities occur in patients. A great danger is nodular hyperplasia, which refers to precancerous conditions and under the influence of adverse factors can provoke thyroid cancer.
Diagnostics
With a visible increase in the volume of the thyroid gland or with the appearance of symptoms of thyroid dysfunction, the patient needs to consult an endocrinologist. During the survey and physical examination, the clinical degree of hyperplasia, the intensity of signs of hyper- or hypothyroidism, provoking factors of such a condition are established. Next, an extended diagnostic program is assigned, which includes the following methods:
- Ultrasound of the thyroid gland. Sonography is indicated for measuring the size of the gland, determining the localization of hyperplastic processes. Ultrasound scanning visualizes a fine-grained structure, smooth borders and rounded contours at the poles. In the Dopplerography mode, an increase in the number of parenchymal vessels is detected.
- Thyroid scintigraphy. The most accurate method of functional examination of an organ, with the help of which areas of increased and decreased hormonal activity are determined. According to the results of the diagnosis, the size and shape of the organ, the presence of local or diffuse signs of hyperplasia are specified.
- CT of the thyroid gland. An informative technique for assessing the structural features of the organ, differential diagnosis between different causes of thyroid enlargement. For a clearer visualization of the thyroid tissue, magnetic resonance imaging is additionally performed.
- Other instrumental methods. If thyroid hyperplasia is accompanied by hormonal disorders, patients are prescribed ECG, EchoCG, abdominal ultrasound. Studies are necessary to assess the degree of systemic disorders against the background of hypo- or hyperthyroidism.
- Hormone tests. For a comprehensive study of the thyroid status, the level of free thyroxine (T4), triiodothyronine (T3), thyroid-stimulating hormone of the pituitary gland is determined. Immunological studies for antibodies to thyroglobulin and thyroperoxidase are also shown.
- Thyroid biopsy. A fine needle aspiration biopsy under ultrasound control is prescribed for nodular forms of hyperplasia in order to exclude the oncological process. The resulting material is subjected to cytological and histological examination.
Differential diagnosis
When making a diagnosis, it is necessary to differentiate the typical causes of hyperplasia: diffuse toxic goiter, subacute and autoimmune thyroiditis, nodular goiter. According to biopsy and instrumental diagnostic methods, primary tumor processes are excluded: adenomas, cysts, malignant neoplasms. Differential diagnosis is also performed with congenital structural abnormalities of the gland.
Treatment
Conservative therapy
Therapeutic measures begin with the correction of nutrition: reducing the consumption of strumogenic products, introducing iodine-rich foods into the daily diet. In acute manifestations of thyrotoxicosis, it is recommended to limit physical activity, exclude the use of alcohol and energy drinks. It is advisable for all patients to give up smoking. Drug therapy is selected differentially and includes the following groups of drugs:
- Iodine preparations. The main line of therapy for endemic goiter, which is aimed at replenishing iodine deficiency and normalizing the hormonal background. Potassium iodide is most often prescribed in individually selected dosages, vitamin and mineral complexes are also used
- Thyrostatics. Drugs that suppress the hormonal activity of the gland are recommended for hyperplasia with hyperthyroidism. They are used for toxic goiter, autoimmune thyroiditis. With insufficient effectiveness of thyrostatics, treatment is supplemented with radioactive iodine.
- Preparations of L-thyroxine. A synthetic analogue of thyroid hormone is necessary for patients with hypothyroidism. It is prescribed under regular monitoring of thyroid-stimulating hormone levels in order to achieve persistent clinical and laboratory euthyroidism.
Surgical treatment
Surgical intervention is prescribed in case of ineffectiveness of conservative therapy of hyperplasia, the occurrence of large nodular neoplasms, a sharp increase in the organ and compression of neighboring anatomical structures. The operation involves subtotal resection of the thyroid gland or total thyroidectomy. The scope of surgical treatment is determined individually.
Prognosis and prevention
Hyperplasia has a benign course, with timely diagnosis and treatment, the outcome of the disease is favorable. However, many patients with hypothyroidism will need lifelong replacement therapy to maintain a stable hormonal background. Without treatment, thyroid pathology progresses, disrupting the work of all organs and causing potentially fatal complications. The main method of prevention is dispensary monitoring of people from risk groups.
Literature
- Ultrasound examination of the thyroid gland/ A.N. Sencha. – 2021.
- Diseases of the thyroid gland / S.V. Yakubovsky. – 2011.
- Diseases of the thyroid gland / E.A. Valdina. – 2006.