thyroid goitre (simple)

Last reviewed 01/2018

Diffuse, non-toxic enlargement of the thyroid may be endemic or sporadic.

Endemic goitres are those which occur at high incidence in certain geographic regions, for example, the Alps, Andes and the Himalayas. They are associated with iodine deficiency but other factors must be involved as the prevalence varies in areas with similar low levels of iodine. Factors such as the intake of goitrogens or metabolic defects in thyroxine synthesis may be important.

Sporadic goitres are less common. Women are affected about 8 times as frequently as men with a peak incidence at puberty or in young adult life. The cause is rarely known but may involve the combined effects of physiological stresses, dyshormogenesis, and goitrogens.

Simple goitres arise from compensatory hyperplasia in an attempt to maintain thyroid hormone levels. Once a state of euthyroidism is reached, colloid accumulates - hence, the term colloid goitre.

The clinical significance depends on the final level of thyroid function achieved. Iodine may cause regression of the goitre in the initial stages but later, is usually without efffect.

The majority of simple goitres progress to a multinodular goitre.