Nodular goiter is a group of thyroid diseases that occur with the development of volumetric nodular formations of various origins and morphology in it. Disease may be accompanied by a visible cosmetic defect in the neck, a feeling of compression of the neck, symptoms of thyrotoxicosis. Diagnosis is based on data from palpation, ultrasound of the thyroid gland, thyroid hormone indicators, fine needle puncture biopsy, scintigraphy, radiography of the esophagus, CT or MRI. Treatment may include suppressive therapy with thyroid hormone preparations, radioactive iodine therapy, hemithyroidectomy or thyroidectomy.
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The term “nodular goiter” in endocrinology refers to the volumetric formations of the thyroid gland belonging to various nosological forms. Signs of nodular goiter are detected in 40-50% of the population; in women, pathology occurs 2-4 times more often and is often combined with uterine fibroids. With the help of palpation, as a rule, nodes exceeding 1 cm in diameter are detected; in more than half of the cases, nodes are not palpated and are detected only during ultrasound of the thyroid gland. A multi-nodular goiter is spoken of if two or more nodular formations are found in the thyroid gland.
The importance of identifying and monitoring patients is due to the need to exclude thyroid cancer, as well as to determine the risk of developing functional thyroid autonomy and thyrotoxicosis, to prevent the occurrence of a cosmetic defect and compression syndrome.
The causes of the development of thyroid nodules are not fully known. Thus, the occurrence of toxic thyroid adenomas is associated with a mutation of the TSH receptor gene and a-subunits of G proteins that inhibit the activity of adenylate cyclase. Inherited and somatic mutations are also found in medullary thyroid cancer.
The etiology of nodular colloidal proliferating goiter is unclear: it is often considered as an age-related transformation of the thyroid gland. In addition, iodine deficiency predisposes to the appearance of colloidal goiter. In regions with iodine deficiency, cases of multi-nodular goiter with thyrotoxicosis are not uncommon.
Risk factors contributing to the development of this disease include:
- genetic disorders (Klinefelter, Down syndrome)
- harmful environmental effects (radiation, toxic substances)
- lack of trace
- elements taking medications
- viral and chronic bacterial and infections, especially chronic tonsillitis.
Taking into account the nature and origin, the following types of pathology are distinguished: euthyroid colloidal proliferating, diffuse nodular (mixed) goiter, benign and malignant tumor nodes (follicular adenoma of the thyroid gland, thyroid cancer). About 85-90% of thyroid formations are represented by nodular colloidal proliferating goiter; 5-8% – benign adenomas; 2-5% – thyroid cancer. Among the malignant tumors of the thyroid gland, follicular, papillary, medullary cancer and undifferentiated forms (anaplastic thyroid cancer) are found.
In addition, the formation of pseudonodes (inflammatory infiltrates and other nodular changes) in the thyroid gland is possible in subacute thyroiditis and chronic autoimmune thyroiditis, as well as a number of other diseases of the gland. Thyroid cysts are often detected together with the nodes.
Depending on the number of nodular formations, a solitary (single) thyroid node, a multi-nodular goiter and a congolomerate nodular goiter are distinguished, which is a volumetric formation consisting of several nodes soldered together.
According to the WHO classification, there are degrees of nodular goiter:
- 0 – no data for goiter
- 1 – the size of one or both lobes of the thyroid gland exceeds the size of the distal phalanx of the patient’s thumb. Goiter is detected by palpation, but is not visible.
- 2 – goiter is determined by palpation and is visible to the eye.
In most cases, nodular goiter has no clinical manifestations. Large nodular formations give themselves away as a visible cosmetic defect in the neck area – a noticeable thickening of its anterior surface. With nodular goiter, the enlargement of the thyroid gland occurs mainly asymmetrically.
As the nodes grow, they begin to squeeze neighboring organs (esophagus, trachea, nerves and blood vessels), which is accompanied by the development of mechanical symptoms of nodular goiter. Compression of the larynx and trachea is manifested by a feeling of a “lump” in the throat, constant hoarseness of the voice, increasing difficulty breathing, prolonged dry cough, attacks of suffocation.
Compression of the esophagus leads to difficulty swallowing. Signs of vascular compression may be dizziness, noise in the head, the development of the syndrome of the superior vena cava. Soreness in the area of the node may be associated with a rapid increase in its size, inflammatory processes or hemorrhage.
Usually, with nodular goiter, the function of the thyroid gland is not impaired, but deviations towards hyperthyroidism or hypothyroidism may occur. With hypofunction of the thyroid gland, there is a tendency to bronchitis, pneumonia, ARVI; pain in the heart, hypotension; drowsiness, depression; gastrointestinal disorders (nausea, decreased appetite, flatulence). Dry skin, hair loss, and a decrease in body temperature are characteristic. Against the background of hypothyroidism, children may experience growth retardation and mental development; women – menstrual disorders, spontaneous abortions, infertility; in men, there is a decrease in libido and potency.
The primary diagnosis is carried out by an endocrinologist by palpation of the thyroid gland. To confirm and clarify the nature of nodular formation, the following is usually performed:
- Ultrasound of the thyroid gland. The presence of a palpable nodular goiter, the size of which, according to ultrasound, exceeds 1 cm, serves as an indication for a fine needle aspiration biopsy. Puncture biopsy of nodes allows to verify the morphological (cytological) diagnosis, to distinguish benign nodular formations from thyroid cancer.
- Assessment of the thyroid profile. In order to assess the functional activity of disease, the level of thyroid hormones (TSH, T4 sv, T3 sv) is determined. The study of the level of thyroglobulin and antibodies to the thyroid gland in nodular goiter is impractical.
- Scintigraphy of the gland. To identify the functional autonomy of the thyroid gland, a radioisotope scan of the thyroid gland with 99mTc is performed.
- X-ray diagnostics. Chest X-ray and esophageal X-ray with barium can reveal compression of the trachea and esophagus in patients with nodular goiter. Tomography is used to determine the size of the thyroid gland, its contours, structure, enlarged lymph nodes.
The treatment of nodular goiter is approached differentially. It is believed that special treatment of nodular colloidal proliferative goiter is not required. If the nodular goiter does not violate the function of the thyroid gland, has a small size, does not pose a threat of compression or a cosmetic problem, then with this form, the patient is dynamically monitored by an endocrinologist. A more active tactic is indicated if the nodular goiter shows a tendency to rapid progression. Treatment may include the following components:
- Drug therapy. With nodular goiter, suppressive therapy with thyroid hormones, therapy with radioactive iodine, surgical treatment can be used. Suppressive therapy with thyroid hormone preparations (L-T4) is aimed at suppressing TSH secretion, which can lead to a decrease in the size of nodular formations and the volume of the thyroid gland in diffuse goiter.
- Surgical treatment of nodular goiter. It is required in case of compression syndrome, visible cosmetic defect, detection of toxic goiter or neoplasia. The volume of resection in nodular goiter can vary from enucleation of the thyroid node to hemithyroidectomy, subtotal resection of the thyroid gland and thyroidectomy.
- Therapy with radioactive iodine (131I). It is considered as an alternative to surgical treatment and is carried out according to the same indications. Adequate dose selection makes it possible to achieve reduction of nodular goiter by 30-80% of its volume.
- Node sclerosis. Methods of minimally invasive destruction of thyroid nodes (ethanol ablation, etc.) are used less often and require further study.
Prognosis and prevention
With nodular colloidal euthyroid goiter, the prognosis is favorable: the risk of developing compression syndrome and malignant transformation is very low. With functional autonomy of the thyroid gland, the prognosis is determined by the adequacy of the correction of hyperthyroidism. Malignant thyroid tumors have the worst prognostic prospects.
In order to prevent the development of endemic nodular goiter, mass iodine prophylaxis (the use of iodized salt) and individual iodine prophylaxis of persons from risk groups (children, adolescents, pregnant and lactating women) is indicated, consisting in taking potassium iodide in accordance with age dosages.