Generality
Housed at the base of the neck, just below the Adam's apple, the thyroid is made up of two glandular lobes, right and left, connected to each other by a thin isthmus placed between the second and fourth tracheal ring. In the adult the lobes of the thyroid measuring approximately 4 cm in length, with a thickness and width normally varying between 1.5 and 2 cm. The total weight of the gland is about 20 grams.
Causes
Any increase in thyroid volume, regardless of its nature, is termed "thyroid goiter". Various and numerous are the possible causes responsible for the "volumetric increase of the thyroid. The gland can grow slightly even in physiological conditions; thyroid hypertrophy is common during pregnancy (+ 13%), while it slightly increases in the first half of the menstrual cycle. . Other times, an enlarged thyroid is a characteristic sign of particular diseases:
- Iodine deficiency: this mineral is essential for the correct synthesis of thyroid hormones; abundant in sea fish and algae, it is also present in trace amounts in vegetables and meat in proportion to the iodine content of the soil. There are some underdeveloped areas of the planet, located in the hinterland or in the highlands, where iodine deficiency is still a serious and particularly widespread problem, which can also be aggravated by the consumption of goitrogenic foods, such as broccoli and cauliflower. thyroid is due to the stimulatory effect of TSH secreted by the pituitary, which - capturing the deficiency of thyroid hormones - releases this hormone in an attempt to increase the endocrine activity of the gland. Enlarged thyroid gland from iodine deficiency is often referred to as "endemic goiter" or "simple goiter".
- Graves 'disease: this is a common cause of hyperthyroidism, a condition caused by the excessive synthesis of thyroid hormones. In people suffering from Graves' disease, abnormal antibodies can be isolated which, by binding to TSH receptors, mimic their action by increasing the endocrine activity of the gland and with it its volume. The enlargement of the thyroid gland depends precisely on this stimulatory effect exerted by the abnormal antibodies.
- Hashimoto's disease: autoimmune disease associated with hypothyroidism, a condition caused by the insufficient synthesis of thyroid hormones. In this case, the abnormal antibodies reduce the endocrine capacity of the gland; similar to iodine deficiency, the enlargement of the thyroid gland related to Hashimoto's thyroiditis is due to the compensatory effect of TSH.
- Multinodular goiter: the thyroid nodules are small clusters of rounded cells, sometimes clearly visible on palpation, which form at the base of the neck. Most of the time these are benign tumors (adenomas or cysts) that are completely asymptomatic, but in some circumstances they can be responsible for hyperthyroidism, or even more rarely develop into a malignant tumor.
- Solitary nodule: compared to the previous case, the thyroid appears enlarged due to the presence of a single large nodule. Generally, the larger the lump and the faster its growth, the greater the risk of a "malignant evolution."
- Thyroiditis: these are inflammatory processes of the thyroid, which increases in volume due to the local accumulation of fluids
- Thyroid cancer: much rarer than thyroid nodules, it usually presents as an abnormal enlargement of one side of the thyroid. In this case the nodular mass is particularly hard and the satellite lymph nodes also increase in volume and consistency.
Symptoms and consequences
In addition to the thyroid ultrasound, which studies the gland from a morphological point of view, evaluating its volume and the presence of any nodules, blood tests are very useful for investigating the state of health of the gland, thanks to the possibility of measuring the plasma concentrations of the gland. TSH, thyroid hormones and abnormal antibodies that characterize some thyroid diseases More laborious investigations include radioactive iodine thyroid scintigraphy and gland biopsy (fine needle aspiration).
The first, useful indications for investigating the nature of the abnormal enlargement of the thyroid derive from the simple observation of the symptoms complained of by the patient. However, these are not always evident: in some cases, in fact, the enlargement of the thyroid is absolutely benign because it does not involve significant alterations in its metabolism; consequently the plasma levels of thyroid hormones appear normal and the patient does not complain of any disturbance; in this case we speak of euthyroid or euometabolic goiter, to differentiate it from the toxic or hyperthyroid (linked to hyperthyroidism) and hypothyroidism (linked to hypothyroidism).
Treatment
Treatment of thyroid goiter depends on the origin and extent of the disorder and related symptoms. When the volume increase of the thyroid is contained, the doctor may decide to periodically monitor the situation without prescribing any specific drug or treatment. Synthetic analogues of thyroid hormones, such as levothyroxine, are prescribed for the treatment of enlarged thyroid associated with hypothyroidism. the article dedicated to drugs for the treatment of hypothyroidism). In the opposite situation, the so-called thyrostatic drugs Methimazole or Thiamazole are prescribed (eg. Tapazole), associated with other active ingredients useful for controlling the symptoms of the disease (eg beta-blockers to counteract arrhythmias and palpitations: see the dedicated article: drugs for the treatment of hyperthyroidism). In case of hyperthyroidism it is also possible to undertake ablative therapy with iodine 131, which destroys the thyroid cells by reducing the volume of the goiter. if the enlarged thyroid gland causes problems such as difficulty in breathing ration and swallowing, or the doctor deems it necessary for the presence of suspicious nodules or a thyroid neoplasm, the gland can be surgically removed.
