Diseases Info

Goiter

Overview | Symptoms | Treatment | Prevention

Overview

Alternative Symptoms names

simple goiter; euthyroid goiter; nontoxic nodular goiter; nontoxic goiter; nontoxic diffuse goiter

Definition

An enlargement of the thyroid gland that is not associated with inflammation or cancer.

Introduction

Goiter, disease of the thyroid gland, characterized by an enlargement of the gland, visible externally as a swelling on the front of the neck. In simple goiter the basal metabolic rate is somewhat lowered, and in toxic goiter it is elevated.

Simple Goiter

This condition is characterized by an enlargement of the entire gland, or of one of its two lobes, caused by a deficiency of iodine in the diet. The disease is especially apt to appear in adolescence. Simple goiter occurs in inland areas of all continents. It was common in what was at one time referred to as the goiter belt of the U.S., which includes the Great Lakes region and inland mountain areas. The administration of iodine, or of the iodine-containing hormone thyroxine, effectively prevents the disease. Prevention requires taking small doses of iodine for long periods. Ingestion of iodine during pregnancy prevents development of the disease in the infant as well as in the mother. Public health measures, including the addition of iodine to water supplies and to table salt, have helped to reduce the incidence of simple goiter in certain areas. Iodine is most effective when administered to children who have the disease. Thyroidectomy, or surgical removal of the gland, may be necessary in cases in which the gland has become greatly enlarged.

Toxic Goiter

This disease, also called exophthalmic goiter, hyperthyroidism, thyrotoxicosis, or Graves' disease, for the Irish physician Robert James Graves, is caused by an excess of thyroxine secretion. The cause of the excessive secretion is obscure. In some cases it may result from excessive stimulation by the pituitary gland. The symptoms of toxic goiter may include a rapid heartbeat, tremor, increased sweating, increased appetite, weight loss, weakness, and fatigue. Some patients have eye problems, such as staring or protrusion. Thiouracil and iodine are sometimes used in the treatment of toxic goiter, as is irradiation of the gland by radioactive iodine.

Causes, incidence, and risk factors

A simple goiter occurs when the thyroid gland is unable to meet the metabolic demands of the body through sufficient hormone production. The thyroid gland compensates by enlarging, which usually overcomes mild deficiencies of thyroid hormone.

A simple goiter may be classified as an endemic (present continuously in a community) or sporadic goiter. Endemic (also known as colloid) goiters are usually caused by inadequate dietary intake of iodine in certain geographical areas with iodine-depleted soil, usually areas away from the sea coast. In the US, the Great Lakes, Midwest, and Intermountain regions are known as the "goiter belt.". The use of iodized table salt prevents this deficiency. The incidence of iodine deficiency is now rare in the U.S. because of widespread distribution of foods from iodine sufficient areas and salt to which potassium iodide has been added.

Sporadic goiters are caused by swallowing of large amounts of certain foods or drugs and do not affect any particular segment of the population. Goitrogenic foods contain substances that decrease thyroid hormone production. Examples of these foods are rutabagas, cabbage, soybeans, peanuts, peaches, strawberries, spinach, and radishes. Drugs include lithium, cobalt, iodides, phenylbutazone, and others.

Hereditary factors may cause goiters. Excessive iodine intake is also a cause of goiter. Risk factors are female, over 40 years old, inadequate dietary intake of iodine, residence in an endemic area, ingestion of large amounts of goitrogenic foods or drugs, and a family history of goiters.

Symptoms

• thyroid enlargement varying from a single small nodule to massive enlargement, neck lump
• breathing difficulties or wheezing from compression of the trachea (rare)
• swallowing difficulties from compression of the esophagus
• neck vein distention and dizziness when the arms are raised above the head

Signs and tests

• thyroid scan
• ultrasound of thyroid
• high or normal thyroid stimulating hormone
• low or normal T4
• normal or increased radioactive iodine uptake
• low urinary excretion of iodine
• antithyroid microsomal antibody

Treatment

Hormone replacement inhibits thyroid stimulating hormone and allows for recovery of the thyroid gland. Small doses of iodine (Lugol's or potassium iodine solution) will treat iodine deficiency. Eliminating or reducing goiter producing foods or drugs is indicated for sporadic goiter. A large goiter that is unresponsive to medical management, or restricts swallowing and breathing, may require partial removal of the gland (subtotal thyroidectomy).

Expectations (prognosis):

The outcome is expected to be good with treatment. Simple goiters may disappear spontaneously, or may become large. Occasionally a person may develop hyperthyroidism with a nodular goiter after receiving excess iodine therapy. More frequently, hypothyroidism develops.

Complications

• A progressive thyroid enlargement and/or the development of hardened nodules may indicate thyroid malignancy.
• A simple goiter may progress to a toxic nodular goiter.
• Thyrotoxicosis may be a side effect of treatment.

Indications For Treatment

• Most small to moderate sized goiters can be treated by providing thyroid hormone in the form of a pill. By supplying thyroid hormone in this fashion, the pituitary will make less TSH which should result in stabilization in size of the gland. This technique often will not cause the size of the goiter to decrease but will usually keep it from growing any larger. Patients who do not respond to thyroid hormone therapy are often referred for surgery if it continues to grow.
• A more common indication for surgical removal of an enlarged thyroid [goiter] is to remove those glands which are enlarged enough to cause compression on other structures in the neck such as the trachea and esophagus. These patients will typically complain of a cough, a slight change in voice, or nighttime choking episodes because of the way that the gland compresses the trachea while sleeping. This X-ray shows how an enlarged right lobe of the thyroid has moved the trachea to the patient's left. The trachea (outlined in light yellow) should be straight from the mouth down to the lungs, but in this patient it is compressed and displaced far to the left. The enlarged gland can even compress the blood vessels of the neck which are also an indication for its removal. More about this on our page examining sub-sternal thyroids.
• As always, suspicion of malignancy in an enlarged thyroid is an indication for removal of the thyroid. There is often a dominant nodule within a multinodular goiter which can cause concern for cancer. It should be remembered that the incidence of malignancy within a multinodular goiter is usually significantly less than 5%. If the nodule is cold on thyroid scanning, then it may be slightly higher than this. For the vast majority of patients, surgical removal of a goiter for fear of cancer is not warranted.
• Another reason (although not a very common one) to remove a goiter is for cosmetic reasons. Often a goiter gets large enough that it can be seen as a mass in the neck. When other people begin to notice the mass, it is usually big enough to begin causing compression of other vital neck structures...but not always. Sometimes the large goiter causes no symptoms other than being a cosmetic problem. Realizing of course, if its big enough to be seen by your neighbors, something needs to be done...medications or surgery or it will most likely continue to get bigger.

Calling your health care provider:

Call your health care provider if you experience any swelling or enlargement in the front of your neck, increased resting pulse rate, palpitations, diarrhea, nausea, vomiting, sweating without exercise of increased room temperature, tremors, agitation, shortness of breath, or signs of hypothyroidism.

Prevention

The use of iodized table salt prevents endemic goiter. Limiting goitrogenic foods and drugs prevents sporadic goiter.

• This picture shows an enlargement of the thyroid (goiter), which can be caused by lack of iodine in the diet, thyroid infection, or excessive thyroid function (hyperthyroidism). Since iodine has been added to table salt, the incidence of goiter has decreased.
• This special scan (scintiscan) shows enlargement of the thyroid gland and extension behind the breastbone (retrosternal space). The false color image was generated by a computer during a radioisotope (I-131) thyroid scan.
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• The term nontoxic goiter refers to enlargement of the thyroid which is not associated with overproduction of thyroid hormone or malignancy. The thyroid can become very large so that it can easily be seen as a mass in the neck. This picture depicts the outline of a normal size thyroid in black and the greatly enlarged goiter in pink. There are a number of factors which may cause the thyroid to become enlarged. A diet deficient in iodine can cause a goiter but this is rarely the cause because of the readily available iodine in our diets. A more common cause of goiter in America is an increase in thyroid stimulating hormone (TSH) in response to a defect in normal hormone synthesis within the thyroid gland. The thyroid stimulating hormone comes from the pituitary and causes the thyroid to enlarge. This enlargement usually takes many years to become manifest.
• This picture depicts the typical appearance of a goiter in a middle aged woman. Note how her entire neck looks swollen because of the large thyroid. This mass will compress the trachea (windpipe) and esophagus (swallowing tube) leading to symptoms such as coughing, waking up from sleep feeling like you cant breath, and the sensation that food is getting stuck in the upper throat. Once a goiter gets this big, surgical removal is the only means to relieve the symptoms. Yes, sometimes they can get a lot bigger than this!