The thyroid is a gland in the lower neck that produces hormone to regulate physiologic functions in your body, such as metabolism (heart rate, sweating, energy consumed). The thyroid is shaped like a bow tie. The two halves (lobes) of the thyroid wrap around either side of the trachea (windpipe) and they are joined by the isthmus, a thin bridge of thyroid tissue that crosses in front of the trachea. Since the thyroid lobes are deep in your neck, you can’t always feel a normal-sized thyroid gland on a neck exam.
Types of Thyroid Disorders
Diseases of the thyroid gland are very common, affecting millions of Americans. The most common thyroid problems are:
- Hypothyroidism, which is an underactive gland that does not produce enough hormone. This may cause symptoms including weight gain, fatigue, and cold intolerance. Hypothyroidism can occur without an identifiable cause, or it may be a result of autoimmune thyroiditis or iodine deficiency.
- Hyperthyroidism, which is an overactive gland that produces too much hormone. This may cause symptoms including weight loss, palpitations, and heat intolerance. Hyperthyroidism may be due to conditions such as Graves’ disease or toxic adenoma.
- Thyroid nodules/cysts. While some growths in the thyroid can affect the amount of hormone released by the thyroid, most actually do not. Many people with thyroid nodules or cysts produce a normal amount of thyroid hormone. Nodules may be benign or malignant (cancerous).
- Thyroid enlargement (goiter). Goiter can develop in a thyroid gland with or without nodules. You can also have a completely normal amount of thyroid hormone even if your thyroid is enlarged. The main concern with goiter is whether or not it causes pressure on the surrounding structures in your neck. This may lead to difficulty swallowing or even difficulty breathing.
- Thyroid cancer. Cancer may occur in a thyroid nodule without causing any symptoms. Although patients with a family history of thyroid cancer or who have had radiation therapy to the head or neck are more prone to developing thyroid cancer, most people diagnosed with thyroid cancer do not have specific risk factors. The most common types of thyroid cancers are very curable, with a 5-year survival rate of greater than 99%.
How is a diagnosis made?
The diagnosis of a thyroid function abnormality or a thyroid mass is made by taking a thorough medical history and a physical examination. In addition, blood tests and imaging studies or biopsy may be required.
Tests your doctor may order include:
- Fine-needle aspiration biopsy
- Blood tests of thyroid function
- Thyroid uptake scan
- CT scan
Abnormalities of thyroid hormone production are typically treated with medications. Thyroid nodules suspicious for cancer or goiters causing compressive symptoms are typically treated surgically. Many small thyroid nodules can be monitored with annual ultrasounds without treatment unless they grow.