In 1656, Thomas Wharton described the distinct nature of what he termed the thyroid gland, distinguishing it from the larynx, as this structure had been considered a laryngeal gland from the time of Andreas Vesalius in the 16th century. It was nearly 200 more years before the function of the thyroid was elucidated. The normal adult thyroid gland weighs 10-25 g and has 2 lobes connected by an isthmus. Goiter is an enlargement of your thyroid gland. Although generally not uncomfortable, goiter may interfere with swallowing or breathing. The possible causes are numerous.

The thyroid is a small, butterfly-shaped gland weighing less than an ounce, located just below your Adam's apple. Hormones produced by your thyroid gland regulate all aspects of your metabolism, from the rate at which your heart beats to the speed at which you burn calories.

Goiter doesn't necessarily mean your thyroid gland isn't producing hormones normally. Even when enlarged, your thyroid may produce below-normal, normal or above-normal amounts of hormones.

Enlargement of the gland can be uniform (diffuse goiter), or the gland may be enlarged due to one or more nodules (nodular goiter). Nodules are lumps within an otherwise normal thyroid gland.

The term goiter comes from the Latin guttur for "throat." Before the early part of the 20th century, the most common cause of goiter was a shortage of iodine in the diet in areas where the soil was deficient in iodine. Without enough dietary iodine, your thyroid can't make and release enough of the two essential iodine-containing hormones.

Goiter became rare after iodized salt was introduced in the 1920s. In addition, iodine naturally occurs in some foods, such as water, dairy products and seafood, or may get into some foods inadvertently during processing. In some parts of the world, goiter is still common because of iodine deficiency.

Signs and symptoms

Signs and symptoms of goiter may include:

• Widespread enlargement of your thyroid gland, resulting in swelling of your neck

• A tight feeling in your throat

• Coughing

• Hoarseness

• Difficulty swallowing

• Difficulty breathing

You may experience other symptoms depending on the underlying cause of the goiter.

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