Goiter

Definition

A goiter is an enlargement of the thyroid gland. It is not cancer.

Causes

There are different kinds of goiters. A simple goiter usually occurs when the thyroid gland is not able to produce enough thyroid hormone to meet the body's needs. The thyroid gland makes up for this by becoming larger, which usually overcomes mild deficiencies of thyroid hormone.

A simple goiter may be classified as either an endemic (colloid) goiter or a sporadic (nontoxic) goiter.

Endemic goiters occur within groups of people living in geographical areas with iodine-depleted soil, usually regions away from the sea coast. People in these communities might not get enough iodine in their diet (iodine is vital to the formation of thyroid hormone). The modern use of iodized table salt in the United States prevents this deficiency. However, inadequate iodine is still common in central Asia, the Andes region of South America, and central Africa.

In most cases of sporadic goiter the cause is unknown. Occasionally, certain medications such as lithium or aminoglutethimide can cause a nontoxic goiter.

Hereditary factors may cause goiters. Risk factors for the development of a goiter include female sex, age over 40 years, inadequate dietary intake of iodine, living in an endemic area, and a family history of goiter.

Symptoms

The main symptom is a swollen thyroid gland. The size may range from a single small nodule to large neck lump.

The swollen thyroid can put pressure on the windpipe and esophagus, which can lead to:

• Breathing difficulties
• Cough
• Swallowing difficulties
• Wheezing

There may be neck vein swelling and dizziness when the arms are raised above the head.

Exams and Tests

The doctor will feel your neck as you swallow. The doctor may be able to feel swelling in the area.

Tests that may be done include:

• Thyroid stimulating hormone (TSH)
• Free thyroxine (T4)
• Thyroid scan and uptake
• Ultrasound of thyroid -- if nodules are present, a biopsy should be done to check for thyroid cancer

Treatment

A goiter only needs to be treated if it is causing symptoms.

Treatments for an enlarged thyroid include:

• Radioactive iodine to shrink the gland
• Surgery (thyroidectomy) to remove all or part of the gland
• Small doses of Lugol's iodine or potassium iodine solution if the goiter is due to iodine deficiency

Outlook (Prognosis)

A simple goiter may disappear on its own, or may become large. Over time, destruction to the thyroid may cause the gland to stop making enough thyroid hormone. This condition is called hypothyroidism.

Occasionally, a goiter may become toxic and produce thyroid hormone on its own. This can cause high levels of thyroid hormone, a condition called hyperthyroidism

Possible Complications

• Hypothyroidism
• Hyperthyroidism
• Thyroid cancer
• Toxic nodular goiter

When to Contact a Medical Professional

Call your health care provider if you experience any swelling in the front of your neck or any other symptoms of goiter.

Prevention

The use of iodized table salt prevents endemic colloid goiter.

Vanderpas J. Nutritional epidemiology and thyroid hormone metabolism. Ann Rev Nutr. 2006; 26:293-322.

AACE/AME. American Association of Clinical Endocrinologists and Associazione Medici Endocrinologi. Medical Guidelines for Clinical Practice for the Diagnosis and Management of Thyroid Nodules. Endocr Pract. 2006 Jan-Feb;12(1):63-102.