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GoiterReferred to goiter enlarged thyroid is an endocrine gland located at the front of the neck, below and on both sides of the trachea and the back of the larynx. Its function is the synthesis of thyroid hormone, which plays an important role in regulating metabolism .
To better understand this disorder, it is necessary to know a number of concepts related to the enlargement of the thyroid:
- Simple Goiter : enlargement of the thyroid gland that is not associated with hyperthyroidism, hypothyroidism, neoplastic process (cancer), inflammatory or autoimmune. Also called non-toxic or toxic goitre.
- Thyroid nodule : is the whole mass of the thyroid gland other than normal consistency. A thyroid nodule can occur for many different diseases, from benign conditions without much significance to thyroid cancer.
- Toxic nodular goiter : enlargement of the thyroid due to the presence in it of several nodules, which also produce excess thyroid hormone. Toxic nodular goiter grows from a simple goiter, and occurs most often in older people.
- Size : goiter is classified from grade 0 (no goiter) to grade 4 (giant goiter), through intermediate grades.
- Form : diffuse goiter, nodular multinodular.
- Epidemiological criteria endemic goiter (occurs in a region in which the prevalence of goiter is relatively high as a result of: iodine deficiency sporadic), or (does not occur in a particular population).
- Cause that produces goiter.
- Functionality : functioning or nonfunctioning goiters.
Goitre Treatment will vary depending on the symptoms it produces. In many cases you opt for expectant management, which is to monitor the time evolution of goiter. In others, when it causes many symptoms, choose to perform more aggressive treatments, such as radiated thyroid, or even remove part or all of it.
Causes of goiterAlthough there are many causes that can cause the appearance of goiter , the specific mechanism by which the thyroid enlargement occurs are still largely unknown. It was found that most patients have subtle alterations of hormone formation. This inability to produce or secrete thyroid hormones, with normal or high TSH level (a hormone synthesized in the pituitary gland that stimulates the thyroid to make thyroid hormone), lead to an enlargement of the gland in an attempt to redress.
The main known causes of goiter include:
- Iodine deficiency : is the most common cause of goiter. It is estimated that around 1,000 million people worldwide are at risk of iodine deficiency, living in areas where the percentage of goiter in the general population is more than 10%.
- Inflammation of the thyroid by different causes thyroiditis, infections, radiation.
- Goitrogens (substances that can promote the development of goiter) monovalent anions, snuff, lithium, iodine, sulfonylureas, salicylates, soybean, sunflower, nuts, peanut ...
- Autoimmune Thyroid Disease : Hashimoto's thyroiditis and Graves' disease.
- Congenital abnormalities (ie already present at birth).
- Infiltrative diseases : Riedel thyroiditis, amyloidosis, hemochromatosis.
- Benign and malignant tumors .
- Puberty, pregnancy .
- Other causes acromegaly, oral contraceptives, hydatidiform mole, and so on.
Epidemiology of goiterThe prevalence of goiter is variable according to each geographical area. In endemic areas the prevalence is higher (more than 10% of the population has goiter, usually due to iodine deficiency), while in non-endemic areas the prevalence is lower (range 3-7%).
Goiter is more common in women, probably because of the higher prevalence of autoimmune diseases and increased iodine requirements during pregnancy and estrogen during adolescence. Finally, we must stress that the thyroid increases in size over the years, so that on the eighth decade of life many people have goiter thyroid in the presence of one or more thyroid nodules.
Symptoms of goiterMost patients have no symptoms at the time of diagnosis, and the presence of goiter is discovered incidentally during a clinical examination performed for other reasons. At other times, the patient goes to his doctor noted on the front of the neck the appearance of a lump or tumor of variable size, which may or may not painful on palpation. most frequent
complication of goitre, when it presents large, is the compression of neighboring structures in the neck, causing patient symptoms such as difficulty breathing , irritating cough , difficulty swallowing , hoarseness or voice changes . Nonetheless, these symptoms'm not very frequent. Patients in which goiter is so large that is introduced into the retrosternal region, the elevation of the arms can cause breathing difficulties, dizziness and even syncope. Prevention of these complications is based on early diagnosis and proper medical treatment. If in spite of this compression of adjacent structures occurs, the treatment is surgical.
Diagnosis of goiterFor a diagnosis of goitre are very important both anamnesis (clinical interview with the doctor about the patient's symptoms) and physical examination, but there are numerous imaging tests available that can provide a very good overview of the anatomy of the thyroid allowing specific diagnosis.
- Anamnesis : must be very detailed, in order to collect as much data as possible. Patients should be questioned about the duration and changes goiter (usually longstanding goiters suggest kindness, while rapidly growing suggest malignancy), the patient's origin (endemic goiter), intake of iodized salt, and consumption of drugs containing iodine or bociógena action, exposure to cervical radiation (increases the risk of thyroid cancer), a family history of thyroid disease (autoimmune diseases), and the presence of local or general compressive symptoms suggestive of thyroid dysfunction.
- Physical examination : a careful examination of the neck should be performed both in normal position as hyperextension. Via palpation it is determined, inter alia, the size, shape and consistency of the thyroid, in the case of diffuse goiter, or define one or more thyroid nodules, whether these are shallow or deep, if the thyroid or not painful to the touch, or if you are or not swollen glands. The normal thyroid gland is not visible, and palpation is an elastic consistency and small size. A nodule of hard consistency, especially if it is attached to adjacent structures, or if accompanied by swollen glands, is suggestive of malignancy.
- Blood analysis : measuring blood of substances such as TSH (thyroid stimulating hormone produced by the pituitary gland), or T4 (thyroid hormone) lets see if overactive or underactive thyroid, which helps guide the diagnosis. However, most of the time is often normal thyroid function and the levels of these substances in the blood are normal. You can also see on the blood test the existence of antibodies against thyroid (its presence geared towards an immunological cause), or other substances such as calcitonin, which guides towards a carcinogenic origin of goitre.
- Plain film : in cases where the goiter is caused by cancer, you can request a chest radiograph to check for metastases in organs such as the lungs.
- Thyroid scan : This test, which consists of irradiating thyroid radioiodine, allows a functional study of the thyroid; ie see what areas capture this radiation and which are not. Thus, thyroid nodules can be hypercaptant or hot (capture more radiation than the rest of the thyroid), temperate (captan radiation similar to the rest of the gland), or hipocaptantes or cold (no feedback).
- Thyroid Ultrasound is the technique of choice for studying the morphology of the thyroid, and that defines the existence of nodules, their size and whether they are solid or cystic; however, no information on the functional activity of the pellets thus not informed of the benign or malignant nature of these. Also control the size of nodules known in time to see your progress or other techniques such as guided puncture of the thyroid.
- Fine needle aspiration (FNA ) allows, without surgery, know the benign or malignant nature of a nodule. FNA can obtain thyroid cells are then studied in the laboratory, and seeing if they are benign or malignant. Is a safe and has few complications, underlying diagnosis of thyroid nodules.
- Surgical biopsy : a portion of the thyroid is removed, or it completely, for further analysis.
Treatment and prevention of goiterThe treatment of goiter depends on the root cause and the symptoms it produces. Regardless of the cause, if the goiter is very large and produce compression symptoms (hoarseness, difficulty breathing or swallowing ...) is usually performed surgical treatment, which involves the removal of part of the thyroid gland ( thyroidectomy ) or all thereof ( total thyroidectomy ). It is necessary to assess, depending on each case (age, sex, previous diseases ...), the risks involved in performing surgery.
goiter When no symptoms therapeutic behavior will be different. In some cases, treatment is only to track the patient from time to time and monitor your progress. Tracking diffuse goiter should include a physical examination including examination of thyroid and lymph nodes as well as the assessment of symptoms, signs and laboratory parameters of thyroid dysfunction. It is therefore important to ask to see analytical control thyroid function. Monitoring can be done every few months or annually, depending on each patient. Another treatment option when no symptoms goiter is based on the suppression of secretion of TSH (thyroid stimulating hormone, secreted by the pituitary gland) by administering a substance called levothyroxine sodium , which is administered in the early stages of the process when it has not yet established the thyroid nodular transformation. Levothyroxine therapy tends to be abandoned over time, as it forces continue treatment for life (upon removal treatment uses goiter), with cardiac side effects and bone level involved. The last therapeutic option is use of radioiodine (iodine-131) , which is the treatment of choice in patients at high surgical risk and clinical compressive. The potential side effects such as inflammation of the thyroid gland (thyroiditis postradioyodo) or hypothyroidism.
Prevention of goitreRegarding the prevention of goiter , you can perform different actions to prevent its occurrence. First, the most important measure is to provide the minimum requirements of iodine to replace urinary losses. WHO recommends the intake of 100-150 micrograms daily or even 200 microgamos daily during pregnancy or lactation for preventing disorders caused by iodine deficiency. The iodine content of foods is generally low, with fish and milk richer in this substance. However, in developed countries the main source of iodine is salt.
Another measure that can be done is to avoid drugs and goitrogens (antithyroid, sulfonylureas, amiodarone, expectorants, isoniazid, salicylates ...), soybean meal or oil sunflower.