Thyroid nodules are abnormal growths on the thyroid gland that may be solid or filled with fluid. The majority of thyroid nodules do not cause any symptoms and only a small percentage are cancerous, but because the thyroid gland is located at the base of the neck, large nodules can sometimes interfere with normal breathing or swallowing. Also, thyroid nodules sometimes affect hormone secretion which may result in other medical problems.
Causes of Thyroid Nodules
Thyroid nodules may appear as cysts, which are fluid-filled, or as solid masses, and may present as a singular nodule or as a multinodular goiter. They may be the result of:
- Iodine deficiency
- Overgrowth of normal thyroid tissue
- Thyroiditis, an inflammation of the gland
- Thyroid cancer
Few thyroid nodules are cancerous, but it may be difficult to ascertain whether a malignancy exists without a fine needle biopsy of thyroid tissue. Neither size nor symptoms alone are indications that a cancer is present, although malignant tumors on the gland frequently enlarge more quickly than benign growths.
Risk factors for Thyroid Nodules
While the development of thyroid nodules is much more common in women than in men, when men develop thyroid cancer, the disease tends to be more aggressive. Risk factors for thyroid nodules may include a family history of thyroid disease, radiation exposure, especially to the head or neck.
Symptoms of Thyroid Nodules
Many patients with thyroid nodules are asymptomatic, unaware that there is a problem until their doctor discovers them during a routine physical examination. If the nodules enlarge, however, they may exert pressure on the windpipe or on the esophagus, interfering with swallowing or breathing. If thyroid nodules affect hormone production, patients may experience a variety of symptoms of either hyperthyroidism or hypothyroidism.
Symptoms of hyperthyroidism include:
- Weight loss
- Nervousness or irritability
- Rapid heartbeat
- Sleep disturbances
- Muscle weakness
- Intolerance to heat
Symptoms of hypothyroidism include
- Weight gain
- Hair loss
- Dry skin
- Intolerance to cold
Treatment of Thyroid Nodules
Treatment of thyroid nodules depends on the type. Often, all that may be required for a benign nodule is watchful waiting. If the nodule has enlarged to the point that it interferes with breathing or swallowing, it will usually require suppressive hormone treatment or surgery. If the patient is experiencing symptoms of hyperthyroidism, radioactive iodine may be administered.
If a thyroid nodule proves to be cancerous, surgery is usually required to remove some or all of the gland. Radioactive iodine may also be prescribed. If a patient has a large part of the thyroid gland removed, hormone replacement will have to be taken for the remainder of the patient's life. This usually presents no problem. Thyroid cancer patients have a very high rate of complete recovery.
Risks of Thyroid Nodules
The most immediately life-threatening risk of thyroiditis resulting from thyroid nodules is thyrotoxic crisis, a sudden and potentially life-threatening intensification of symptoms that requires emergency care. There is also a risk that hyperthyroidism may result in heart problems or osteoporosis. While there is a risk that thyroid nodules may be cancerous, since malignancies of the thyroid gland are usually found in their early stages, they respond well to treatment. Patients with thyroid cancer almost always have a good prognosis.