Goiter
A goitre (or goiter) (Latin struma), also called a bronchocele, is a swelling in the neck (just below Adam's apple or larynx) due to an enlarged thyroid gland.
They are classified in different ways:
* A "diffuse goitre" is a goitre that has spread through all of the thyroid (and can be a "simple goitre", or a "multinodular goitre").
* "Toxic goitre" refers to goitre with hyperthyroidism. These most commonly due to Grave's disease, but can be caused by inflammation or a multinodular goiter.
* "Nontoxic goitre" (associated with normal or low thyroid levels) refers to all other types (such as that caused by lithium or certain other autoimmune diseases).
Causes
The most common cause for goitre in the world is iodine deficiency (E01); this condition is commonly called endemic goitre. It is curable by mass food-supplementation with iodine (in the form of iodide or iodate), and today remains a problem only in the least affluent countries which lack economic resources to fortify foods with iodine as part of public health programs.
Other causes are:
* Hashimoto's thyroiditis (E06.3)
* Graves-Basedow disease (E05.0)
* inborn errors of thyroid hormone synthesis, causing congenital hypothyroidism (E03.0)
* Thyroiditis (acute, chronic) (E06)
* Side-effects of pharmacological therapy (E03.2)
Iodine is necessary for the synthesis of the thyroid hormones triiodothyronine and thyroxine (T3 and T4). In conditions producing endemic goitre, when iodine is not available, these hormones cannot be made. In response to low thyroid hormones, the pituitary gland releases thyroid stimulating hormone (TSH). Thyroid stimulating hormone acts to increase synthesis of T3 and T4, but it also causes the thyroid gland to grow in size by increasing cell division.
Goitre is more common among women, but this includes the many types of goitre caused by autoimmune problems, and not only those caused by simple lack of iodine.