<unk>  is the abnormal enlargement of the thyroid gland. Development of<unk>  doesn't imply the malfunction of the thyroid gland and<unk>  occurs in a gland which is either in hypothyroid, euthyroid or hyperthyroid state. Lack of iodine in the diet is the most common cause of<unk> s worldwide.<unk>  is usually painless but if large in size may lead to compression symptoms such as dysphagia, dyspnea and hoarseness of voice. Ancient documented texts with reference to<unk>  have been seen dating back to 2700 BC. In 1949, commercial synthesis of levothyroxine was done successfully. In 1974, an international committee of thyroid pathologists published the first WHO histological classification of thyroid tumors which had served as a basis for various clinical, pathological, and epidemiological studies.<unk>  may also be classified according to various classification methods based on etiologic, epidemiological, anatomical, pathological, functional and morphological factors. When the TRH-TSH thyroid hormone axis is interfered, it results in the structural and functional changes of the thyroid gland. Increased TSH production is triggered by a deficiency in thyroid hormone synthesis or intake. In order to normalize thyroid hormone levels, the increase in TSH leads to increased cellularity and hyperplasia of the thyroid gland and when this process is continuous, it leads to<unk> . Various factors have been associated with the cause of<unk>  such as hereditary, hormonal, dietary, pharmacological, physiological, environmental and pathological factors. The most common causes being, iodine deficiency, Grave's disease and Hashimoto's disease.<unk>  may be caused by a mutation in the genes such as the thyroglobulin (Tg) gene, thyroid-stimulating hormone receptor (TSHR) gene and the sodium-iodide symporter (NIS) gene. As<unk>  manifests in a variety of clinical forms, differentiation must be established in accordance with the particular sub-type. The incidence of<unk>  is approximately 1400 - 1700 per 100,000 individuals in females and 900 per 100,000 individuals in males, worldwide. The prevalence of<unk>  is approximately 3000 per 100,000 individuals worldwide, for single thyroid nodules. The frequency of<unk>  increases in women over 45 years of age. The rate of occurrence of<unk>  in females is higher than that in males by a ratio of 4:1. There is no racial predilection to<unk> . Screening for<unk>  initially involves physical examination followed by blood tests for free T4 and TSH and finally thyroid scan, ultrasound and biopsy to rule out malignancy. Slow growth of the nodules is observed in benign<unk> . Rapid growth and large size of<unk>  causing compressive symptoms may be suggestive of thyroid cancer. Common complications of<unk>  include those related to the enlarged gland and to thyroidectomy. Prognosis is generally good for benign<unk> . Although the prognosis is good and the risk is low, caution is advised for the possible development of malignancy. Careful monitoring of size, shape and consistency associated with pain is advised. Radiation exposure has been attributed to the possible development of malignancy. A history of low iodine intake, history of use of therapeutic drugs that hinder normal thyroid hormonal activity, radiation exposure and positive family history of thyroid diseases. Symptoms of<unk>  include, swelling at the base of the neck, dysphagia, hoarseness of voice and dyspnea. Physical examination of patients with<unk>  is usually remarkable for swelling at the base of the neck. Patients with<unk>  may be in a euthyroid, hypothyroid or hyperthyroid state. Patients should be evaluated for free T4, T3, TSH levels and TPO antibodies. Plain x-ray findings of the neck suggestive of<unk>  include tracheal deviation or compression and calcification within the<unk> . Ultrasound may be helpful in determining the physical characteristics of the thyroid gland and also aids in ultrasound guided FNAC. Thyroid radioisotope scan may be helpful in the diagnosis of<unk> . Barium swallow may be helpful in assessing compression of the esophagus due to<unk> . Indirect laryngoscopy helps assess the mobility of the vocal cords. Pharmacologic therapy for<unk>  involves normalizing hormone levels and treating the inflammation. Treatment regimen involves Lugol’s iodine, antithyroid drugs and β-adrenergic blockers. In some cases, radioactive iodine may be used to treat an overactive thyroid gland. Thyroid surgery may be advised in cases of<unk>  depending upon the symptoms and extent as well as type of gland pathology such as, compressive symptoms, thyroid hyper-functioning and thyroid cancer. Effective measures for the primary prevention of<unk>  include iodine supplementation and smoking cessation.
Goiter
Goitre
Acne
Skin nodules
Deafness
Dry eyes
Airsickness
Chalicosis