The thyroid is a small butterfly-shaped gland that sits in front of the trachea or windpipe. It is responsible for producing thyroid hormone (T4 and T3), which is involved in regulation of metabolism, bowel function, heart rate, temperature sense, menstrual regularity, and other functions. The thyroid is controlled by the pituitary gland in the brain. The pituitary gland produces Thyroid Stimulating Hormone (TSH), which controls the secretion of hormone from the thyroid gland.
There are two general reasons to see a doctor about your thyroid: problems with thyroid function (hormone levels) and thyroid nodules (a lump or growth in the thyroid). Please see below for more detailed answers.
Signs and symptoms of low thyroid function are highly variable from person to person. Symptoms of an underactive thyroid may include fatigue, weight gain, cold intolerance, more sluggish bowels, dry skin, brittle nails, hair loss, muscle pains, mood changes and alteration in menstrual cycle. But, these symptoms are non-specific and may be due to other issues if thyroid levels are within normal limits.
The main causes of underactive thyroid (primary hypothyroidism) are surgery (thyroid removal), radioactive iodine treatment (to destroy the thyroid gland) and chronic autoimmune hypothyroidism or Hashimoto’s Thyroiditis. Hashimoto’s Thyroiditis is defined by the presence of an antibody that may impact thyroid function over time. A far more significant percentage of the population has thyroid antibodies (11% in some studies) than have low thyroid function (4% in some studies). This means that even if you do have the antibody, your thyroid function may remain normal and you may not require thyroid replacement medication.
If you are concerned that your thyroid is not functioning properly, Thyroid Stimulating Hormone (TSH) is the initial blood test to check. TSH is the most sensitive test for thyroid dysfunction because small changes in T4 levels cause relatively larger changes in TSH. Further evaluation can be done with free T4 levels and antibodies for Hashimoto’s Thyroiditis, in the appropriate clinical setting.
Thyroid nodules are lumps or growths of the thyroid. Thyroid nodules may be discovered on routine physical examination, incidentally on imaging (CT or MRI scans of the chest, spine or ultrasounds of the carotid arteries). Thyroid nodules are common and increase in frequency with age. By the age of 45, up to half of normal people have thyroid nodules that can be seen on an ultrasound. Fortunately, about 95% of thyroid nodules are benign. Further evaluation of thyroid nodules will include complete history, dedicated thyroid ultrasound and fine needle aspiration biopsy, if needed. If thyroid nodules are large and cause symptoms such as difficulty swallowing, change in voice or neck pressure, they may require removal by a surgeon.
Most thyroid nodules do not cause any symptoms. Some thyroid nodules show up as a visible lump in the neck. Thyroid nodules usually move up (and then down again) with swallowing. When thyroid nodules become large (>4 cm or 1.5 in) they may cause compressive symptoms. Early compressive symptoms include discomfort with swallowing, discomfort when lying down in certain positions, a tight feeling when wearing a collared shirt, and noisy breathing at night. Advanced compressive symptoms including food getting stuck in the throat, decreased exercise tolerance, and difficulty breathing.
Thyroid nodules may be found to be benign (non-cancerous), cancerous or indeterminate on fine needle aspiration biopsy. Indeterminate means that we cannot be certain whether a thyroid nodule is benign or cancerous. Within the indeterminate category, there are additional, more specific categories that are each associated with a risk of cancer. These include Atypia of Undetermined Significance (AUS) or Follicular Lesion of Undetermined Significance (FLUS); Suspicious for Follicular Neoplasm (SFN) or Suspicious for Cancer. Indeterminate cases including AUS, FLUS and SFN, which carry a 10-30% risk of cancer, were traditionally managed with surgical removal of part of the thyroid in order to establish a definitive diagnosis. Now, molecular profile testing is available to provide additional genetic information on these nodules which may allow more patients to avoid surgery, in appropriate cases.
There are no scientifically supported non-surgical treatments for thyroid nodules. In other words, observation (watchful waiting) is the alternative to surgery. Because most thyroid nodule are benign and small (<4 cm or 1.5 in), the majority of thyroid nodules do not require surgery. In the past, some patients were given thyroid hormone medication in an effort to “suppress” their nodules. This has been shown to be ineffective and is no longer done.
Signs and symptoms of overactive thyroid function or hyperthyroidism may include racing heart, tremulous hands, intolerance to warm temperatures, sweating, weight loss, increase in appetite and loose stools. Again, symptoms are highly variable from person to person. But, these symptoms are non-specific and may be due to other issues if thyroid levels are within normal limits. The main causes of overactive thyroid or hyperthyroidism are an autoimmune condition called Graves Disease, toxic single nodule or multiple toxic nodules, or a transient inflammation of the thyroid gland called thyroiditis. Identifying the underlying cause of hyperthyroidism is very important as each condition is managed differently. Management may include anti-thyroid medication, radioactive iodine, surgery or monitoring.
Thyroid cancer is a cancer that arises in the thyroid tissue and/or surrounding lymph nodes. Thyroid cancer is the fastest growing cancer among women. Women are more than twice as likely to be diagnosed with thyroid cancer than men. Although the incidence of thyroid cancer is increasing, death rates have not changed significantly over the past ten years.
There are multiple types of thyroid cancer: papillary thyroid cancer, follicular thyroid cancer, medullary thyroid cancer, and anaplastic thyroid cancer. The initial management of thyroid cancer is surgery to remove the thyroid gland. Your surgeon may choose to do either a total thyroid removal or remove a lobe of the thyroid gland, depending on the pathology diagnosis. Surgery may be followed by radioactive iodine, in appropriate cases. Any patient who has had their thyroid removed will require life-long thyroid medication.
Most thyroid cancers are discovered as a lump in the lower middle portion of the neck. Sometimes these are discovered by the patient, and more frequently they may be found on a routine physical examination or a scan of the neck. In a fraction of patients, thyroid cancer may move to neck lymph nodes and show up as a lump in the side of the neck. A rapidly growing thyroid cancer can cause pressure and discomfort in the neck, and some men may note difficulty in buttoning a collared shirt. Symptoms of advanced thyroid cancer include trouble breathing, a hoarse voice, difficulty swallowing, and even bone pain if the cancer has moved to the bones.
Thyroid cancer treatment is very successful. About 95% of thyroid cancer patients live more than five years, and most thyroid cancer patients experience a normal life span and full quality of life after appropriate treatment. Even patients with advanced thyroid cancer may often do well with modern targeted therapies.
Treatment options for recurrent thyroid cancer include additional surgery, use of radioactive iodine and in some cases, chemotherapy or tyrosine kinase inhibitors. The choice of further treatment often hinges on the location of the recurrent disease. Diseased lymph nodes in the neck are usually removed surgically. Disease outside the neck is often treated with radioactive iodine, external beam radiation, chemotherapy, or combination treatments.
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