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

There are different kinds of goiters. A simple goiter can occur for no known reason, or 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.

There are two types of simple goiter:

• Endemic (colloid) goiter
• Sporadic (nontoxic) goiter

Goiters occur in groups of people who live in areas with iodine-poor soil. These regions are usually away from the sea coast. People in these communities might not get enough iodine in their diet (iodine is needed to produce thyroid hormone).

The use of iodized table salt in the United States today prevents iodine deficiency. However, a lack of enough 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.

Inherited factors may cause goiters. Risk factors include:

• Age over 40 years
• Family history of goiter
• Female gender
• Living in an area where people do not get enough iodine
• Not getting enough iodine in the diet

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.

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:

• Free thyroxine (T4)
• Thyroid scan and uptake
• Thyroid stimulating hormone (TSH)
• Ultrasound of thyroid

If nodules are found on ultrasound, a biopsy should be done to check for thyroid cancer.

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
• Treatment with thyroid hormone supplements if the goiter is due to underactive thyroid

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.

• Difficulty swallowing or breathing
• Hypothyroidism
• Hyperthyroidism
• Thyroid cancer
• Toxic nodular goiter

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

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.

Ladenson P, Kim M. Thyroid. In: Goldman L and Ausiello D, eds. Goldman: Cecil Medicine. 23rd ed. Philadelphia, Pa:Saunders; 2007:chap 244.