Thyroid Goiter

Generality

The term goiter, or struma, indicates the increase in volume and weight of the thyroid, a small butterfly-shaped gland located just below the Adam's apple.

It manifests itself with a more or less evident and symmetrical bulge of the neck, and can recognize different causes, just as the repercussions of the goiter on the health of the individual are different; in fact, the hormones produced by the thyroid regulate every aspect of the body's metabolism, such as the heart rate, temperature and speed of use of carbohydrates and lipids for energy purposes.

Index Section

Enlarged Thyroid Causes, Classification and Types of Goiter Symptoms Goiter Symptoms and Complications Diagnosis Treatment and therapy

Causes and types of goiter

ENDEMIC GOZZO

In the past, goiter was widespread in areas prone to iodine deficiency in water and food; there was therefore talk of endemic goiter to emphasize the modest and limited extent of the epidemic. In the absence of an adequate quantity of this mineral, in fact, the thyroid cannot synthesize and release two very important hormones containing iodine, thyroxine (T4) and triiodothyronine (T3). If the hormonal synthesis is insufficient there is an increase in the hormone TSH or thyrostimulant, secreted by the pituitary gland to stimulate the production of thyroid hormones; the excessive secretion of TSH for compensatory purposes causes an increase in the volume of the thyroid gland, hence the goiter.

To cope with the alarming spread of endemic goitre, the practice of adding iodine to flour, water or cooking salt has been introduced in many countries, a choice that has greatly reduced the incidence of the disorder. Remember, again with regard to the endemic goiter, that some foods - not surprisingly called "gozzigeni" - can predispose to the disorder if inserted in a diet already lacking in iodine; these include cabbage, cabbage, turnips and the milk of cows fed with these vegetables.

The endemic goiter is a non-toxic goiter, first widespread and then, due to a long-term iodine deficiency, multinodular; can transform into hyperfunctioning toxic goitre (basedowifyire) if treated with high doses of iodides.

SPORADIC GOZZO

The goiter is due to endogenous causes, for example the presence of a tumor or other pathologies, or to the taking of antithyroid drugs. Within a given population, these are isolated cases, hence the name "sporadic" which distinguishes this type of goiter from the endemic one, defined as such only when present in over 10% of the general population or in more than two children in school age of one hundred.

CONGENITAL GOZZO

Goiter is caused by genetic defects of thyroid hormone (enzymatic alterations etc.).

ETOROIDEO or EUMETABOLIC GOZZO and TOXIC GOZZO

The presence of goiter does not necessarily mean inability to secrete adequate amounts of thyroid hormones. Although it is conspicuously enlarged, this gland can in fact have a normal, reduced or even increased activity; in the first case we speak of euthyroid goiter, simple goiter or non-toxic goiter, to indicate the maintenance of functionality despite the increase in volume and the lack of association with inflammatory or neoplastic processes; in the second case we speak of hypothyroid goiter and in the third case of hyperthyroid goiter or toxic goiter. According to what has been said, the "non-toxic" attribute belongs to both the eumetabolic and hypothyroid goitre.

When it is caused by hyperthyroidism, the goiter is accompanied by an increase in metabolic activity, tachycardia, tremors, sweating and excessive weight loss; the opposite symptoms are typical of hypothyroidism.

On the other hand, not all thyroid diseases cause goiter, such as those due to an insufficient response to pituitary TSH by the thyrocytes (thyroid cells).

In addition to a lack of iodine in water and food, combined or not with the ingestion of particular foods, simple goiter can be linked to the intake of certain drugs (especially thyrostatic substances, such as thiouracil and potassium percolate; in the presence of an individual predisposition, also other medicines, like paraminosalicylic acid, amiodarone, sulfaniluree and phenylbutazone, can favor the onset of goiter) or from genetic defects of thyroid hormone.

As anticipated for the endemic one, the eumetabolic goitre is at first uniform or diffused and evolves over time in nodular goiter (lumpy appearance).

DIFFUSED GOZZO AND NODULAR GOZZO

The increase in thyroid volume can be uniform and involve the whole gland (diffuse, with a symmetrical appearance and smooth like the goiter colloid of adolescents), or asymmetric, with hypertrophy and hyperplasia limited to one or more nodules (uninodular or multinodular goiter with cocoon appearance). Most of these bumps have a benign origin and as such do not cause cancer; non-toxic multinodular goiter can become hyperfunctional (multinodular toxic goiter) spontaneously or when treated with high doses of iodides.

GOTO ESOFTALMICO, DIFFUSE TOXIC GOZZO or BASEDOWIAN GOZZO

It is due to an autoimmune disease known as Graves' or Basedow's disease, more widespread in the female sex and associated with hyperthyroidism, that is to an exaggerated production of thyroid hormones. The disease manifests itself, among other things, with a widespread toxic (uniform) goiter.