Goiters are generally caused by non-malignant enlargement of the thyroid gland. They can become quite large and cause neck discomfort. If they become large enough, they can interfere with swallowing and can obstruct the trachea. Some of these goiters can extend into the chest and are known as substernal goiters.
There are two forms of multinodular goiters: 1) nontoxic MNG and 2) toxic MNG. If the goiter makes normal amounts of thyroid hormone, it is known as a non-toxic MNG. If the goiter makes higher than normal amounts of thyroid hormone leading to a suppressed TSH, it is known as a toxic MNG.
Causes of Goiters
The exact causes of thyroid nodules or multinodular goiters are unknown. In general, the development of goiter is due to a complex mix of genetic and environmental factors. Iodine deficiency as a cause of goiter is rare in North America and most of Europe. However, even in areas of iodine deficiency most patients do not develop goiters.
Symptoms of non-toxic MNG may be non-existent. If the goiter is very slow growing and long-standing, the patient may not notice the slow increase in size. However, some patients may complain of a feeling of fullness in the neck, a choking sensation, difficulty swallowing large pills or chunky foods, a sense of pressure on the neck, or worsening snoring, especially with MNG that grow beneath the breastbone (i.e. substernal goiter).
If you have one or more of the above symptoms, it does not mean that you have a goiter. If you think you have a goiter, please call your doctor.
The natural history of benign goiter is usually slow growth of the nodules. Therefore, observation can be safe. If there is a suspicion of the nodules harboring cancer, the goiter is growing quickly, or if the goiter's large size is causing compressive symptoms, such as hoarseness, difficulty swallowing, or difficulty breathing, use of thyroid hormone to attempt to "suppress" and shrink MNG is not used because it puts patients at risk for hyperthyroidism.
Surgery for a goiter is used when a dominant nodule is suspicious for malignancy, the goiter is growing rapidly, or there are compressive symptoms due to the size of the goiter. The extent of surgery is based on the suspicion for malignancy, presence of thyroid dysfunction, and presence of bilateral nodules. In patients who have normal thyroid function, with compressive symptoms due to a single nodule, with a benign biopsy, and no nodules on the opposite side, unilateral thyroid lobectomy is appropriate. Otherwise, total thyroidectomy is the operation of choice.
Other non-surgical options may be available in the treatment of goiters. For non-surgical options, you should contact your endocrinologist.