The term “goiter” simply refers to the abnormal enlargement of the thyroid gland. It is important to know that the presence of a goiter does not necessarily mean that the thyroid gland is malfunctioning or that there is a cancerous tumor. A goiter can occur in a gland that is producing too much hormone (hyperthyroidism), too little hormone (hypothyroidism), or the correct amount of hormone (euthyroidism).
One of the most common causes of goiter formation worldwide is iodine deficiency. In the United States and other developed countries iodine deficiency is no longer a problem. The primary action of the thyroid gland is to concentrate iodine from the blood to make thyroid hormone. When there is insufficient iodine, thyroid hormone is not secreted and the gland enlarges because of stimulus from thyroid stimulating hormone (TSH).
Multinodular goiters are another common cause of goiters. Individuals with this disorder have one or more nodules within the gland which cause thyroid enlargement. This is often detected as a nodular feeling gland on physical exam. Patients can present with a single large nodule or with multiple smaller nodules in the gland when first discovered. Thus, in early stages of a multinodular goiter with many small nodules, the overall size of the thyroid may not be enlarged yet. Unlike the other goiters discussed, the cause of this type of goiter is not well understood.
Other common causes of goiter in the US are autoimmune diseases such as Grave’s Disease or Hashimotos Thyroiditis.
The diagnosis of a goiter is usually made at the time of a physical examination when an enlargement of the thyroid is found. Simple laboratory tests are also done to determine if the gland is overactive or underactive.
Other tests used to help diagnose the cause of the goiter may include a radioactive iodine scan, thyroid ultrasound, or a fine needle aspiration biopsy. If the goiter is significantly enlarged, CT scan (CAT scan) may be done to determine the extent of the enlargement.
The treatment will depend upon the cause of the goiter. If the goiter was due to a deficiency of iodine in the diet (not common in the United States), you will be given iodine supplementation given in liquid or pill form. This will lead to a reduction in the size of the goiter, but often the goiter will not completely resolve.
If the goiter is due to Hashimoto’s Thyroiditis, and you are hypothyroid, you will be given thyroid hormone supplement as a daily pill. This treatment will restore your thyroid hormone levels to normal, but does not usually make the goiter go completely away. Although appropriate in some individuals, surgery is usually not routine treatment of thyroiditis.
If the goiter is due to hyperthyroidism, the treatment will depend upon the cause of the hyperthyroidism. For some causes of hyperthyroidism, the treatment may lead to a disappearance of the goiter. For example, treatment of Graves’ disease with radioactive iodine usually leads to a decrease or disappearance of the goiter. Surgery may be required in some individuals who do not respond to the medical therapy or radioactive iodide.
Multinodular goiters are frequently monitored closely with ultrasounds and fine needle biopsies. If one of the nodules has cancer cells or is suspicious for cancer you may require surgery.
If the goiter that so large that it constricts the airway, compresses the esophagus, or causes significant deformity your doctor may suggest that the goiter be treated by surgical removal.
Whatever the cause, it is important to have regular monitoring when diagnosed with a goiter.
Further Information can be found on the American Thyroid Website at www.thyroid.org