It is the most common of all disorders of the thyroid gland.
It is the result of the genetic heterogeneity of the follicular cells and apparent acquisition of new cellular qualities that become heritable.
Nodular goiter is most often detected simply as a mass in the neck, but sometimes it is a gland that enlarges and produces pressure.
Hyperthyroidism develops in a large proportion of the multinodular defect after a few decades, often after excess iodine.
A multinodular goiter is simply a thyroid gland that usually enlarges and contains multiple thyroid nodules.
The nodules can be very small, often only a few millimeters in size, or the nodules can be larger, perhaps several cm each.
There are usually two questions that need to be answered in patients with a multinodular goiter. The first question is usually:
Are all nodules benign?
The focus of this question depends on the clinical presentation, the associated risk factors, the size of the nodules and whether the nodules work or do not work.
The diagnosis is based on the physical examination. The results of the thyroid function test are normal or indicate subclinical or overt hyperthyroidism.
Imaging procedures are useful for detecting details such as distortion of the trachea and for providing an estimate of volume before and after therapy.
4 to 17% of multinodular goiter cases meet the criteria for malignant change, however, most of these lesions are not lethal.
If a clinical and multinodular goiter is small and does not produce any symptoms, the treatment is controversial.
The T4 given to reduce the gland or to prevent further growth is effective in about one third of patients.
The normal thyroid gland is a fairly homogeneous structure, but nodules are often formed within its substance.
These nodules can be only the growth and fusion of localized colloidal follicles, or more or less discrete adenomas, or cysts.
Nodules greater than 1 cm can be detected clinically by palpation.
A careful examination reveals its presence in at least 4% of the general population. Nodules less than 1 cm in diameter that are not clinically detectable unless located on the surface of the gland are much more frequent.
The terms adenomatous goiter, nontoxic nodular goiter and colloid nodular goiter are used interchangeably as descriptive terms when a multinodular goiter is found.
A goiter simply means enlarged thyroid. A goiter can be a simple goiter where the entire thyroid is larger than normal or a multinodular goiter where there are multiple nodules.
Multinuclear goiters can be either a toxic multinodular goiter (that is, it produces too much thyroid hormone and causes hyperthyroidism) or nontoxic (that is, it does not produce too much thyroid hormone).
It is not known what causes multinodular goiters in most cases, but it has been shown that iodine deficiency (that is, very little iodine in the diet) and certain genetic factors lead to multinodular goiter.
Signs and symptoms.
Most multinodular goiters do not cause symptoms and are discovered on a routine physical examination or during a test that is done for another reason. Patients with a toxic multinodular goiter may have signs and symptoms of hyperthyroidism.
If the goiter is large enough, patients may present compression symptoms that may include difficulty breathing (especially when lying down), food or pills that “get stuck” in the throat, a feeling of suffocation in the neck.
These symptoms occur most commonly if the goiter is growing down into the chest, called a substernal goiter. If the goiter is large enough, it can be visible.
Non-toxic multinodular goiter symptoms may be non-existent.
If the goiter is very slow growing and long-lasting, the patient may not notice the slow increase in size. However, some patients may complain of:
- a feeling of fullness in the neck.
- Choking sensation
- Difficulty swallowing large pills or thick foods
- Sensation of pressure in the neck or worsening of snoring, especially with multinodular goiter that grows below the sternum.
If a multinodular goiter is detected or suspected, a detailed medical history and physical examination should be done.
History is important and includes the rapidity with which the thyroid is growing, risk factors for thyroid cancer (family history of cancer and a history of radiotherapy in the neck or chest), family history of goiter, hoarseness and symptoms of hyperthyroidism.
Important results of the physical examination include a goiter that can be felt, the growth down in the chest, and enlarged neck veins.
After a complete history and physical examination, a thyroid ultrasound should be performed. There is no associated radiation. It is the best test to observe the thyroid and will allow the doctor to see the size of the thyroid and the specific characteristics of the nodule.
For example: size, number of nodules, if there are calcifications (calcium deposits), ecotexture (that is, how bright or dark it looks), edges, shape and whether it is solid or cystic (ie, filled with liquid).
The appropriate treatment of a multinodular goiter depends on the size, the rapidity in which it is growing, the results of examinations, the risk of cancer.
But also, the symptoms of compression and if the goiter is large enough to be cosmetically unattractive.
In general, if the goiter is growing rapidly, it grows steadily over time, is worrying for cancer, is causing compression symptoms, is growing underground, it must be eliminated (ie thyroidectomy).
The natural history of benign goiter is usually a slow growth of the nodules. Therefore, the observation can be safe.
The multinodular goiter is treated if there is suspicion of nodules that harbor cancer, the goiter is growing rapidly, or if the large size of the goiter is causing compression symptoms, such as hoarseness, difficulty swallowing or difficulty breathing.
The use of thyroid hormone to try to “suppress” and reduce multinodular goiter is not indicated and puts patients at risk for hyperthyroidism.