Thyroid nodules are solid or fluid-filled lumps that form within the thyroid gland. Most thyroid nodules are harmless and don’t cause symptoms, but a small percentage are cancerous. Some thyroid nodules may become large enough to make it difficult to swallow or breathe.
Large thyroid nodules may be felt, seen and cause shortness of breath or difficulty swallowing.
Some thyroid nodules may produce additional thyroxine, a hormone released by the thyroid gland, and cause a condition called hyperthyroidism. Symptoms of this condition include:
- Unexplained weight loss
- Increased sweating
- Rapid or irregular heartbeat
Signs of low thyroid hormones (a condition called hypothyroidism) include:
- Feeling cold
- Dry skin
- Memory problems
Complications associated with thyroid nodules may include difficulty swallowing or breathing, hyperthyroidism and problems related to thyroid nodule surgery.
Thyroid nodules may be caused by numerous factors such as:
- Overgrowth of normal thyroid tissue (thyroid adenoma) that isn’t cancerous or serious unless its size causes symptoms; may lead to hyperthyroidism
- Thyroid cysts are fluid-filled cavities usually caused by degenerating thyroid adenomas; may include solid components; typically non cancerous but may contain cancerous solid components
- Multinodular goiter is a condition in which part of the thyroid gland is enlarged; may be caused by iodine deficiency or a thyroid disorder
- Chronic inflammation of the thyroid may be associated with hypothyroidism
- Iodine deficiency may cause the thyroid gland to develop thyroid nodules
When to Consult a Doctor
Patients who feel or see a thyroid nodule, or experience troubling symptoms, should schedule a visit to their physician’s office. During the initial visit, the physician will perform a physical exam and observe the patient’s thyroid gland as the patient swallows.
The physician will check for signs of hyperthyroidism, such as heart palpitations, overly active reflexes and tremor. The physician will also check for signs of hypothyroidism, such as dry skin, facial swelling and a slow heartbeat.
Patients may need to obtain thyroid function tests that will measure blood levels of thyroid-stimulating hormone (TSH), thyroxine (T4) and triiodothyronine (T3). The physician may also request a thyroid ultrasound to obtain images of the thyroid gland. A thyroid ultrasound test will help doctors distinguish cysts from solid nodules or determine if multiple nodules are present.
A fine-needle aspiration biopsy may be performed to screen for cancer. The samples will be analyzed in a laboratory under a microscope. A thyroid scan will help evaluate thyroid nodules.
Benign thyroid nodules may be treated with thyroid hormone therapy or surgery. Thyroid nodules that inhibit breathing or swallowing may be surgically removed.
Nodules that cause hyperthyroidism may be treated with radioactive iodine, anti-thyroid medications or surgery. Radioactive iodine may be taken as a capsule or in liquid form and will help shrink the nodules and alleviate symptoms, typically within two to three months. Anti-thyroid medications such as methimazole are typically long-term, but may have serious side effects on the liver.
An overactive thyroid nodule that doesn’t respond to radioactive iodine or anti-thyroid medication may need to be surgically removed.
Cancerous thyroid nodules are typically treated with surgery.