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First let’s understand what the thyroid gland does. When working properly, the thyroid is a vital component of our endocrine system. The thyroid produces thyroid hormone which is released into the bloodstream to regulate our body’s metabolism. The pituitary gland in the brain actually controls the amount of thyroid hormone released by producing Thyroid Stimulating Hormone, or TSH. An overactive or underactive thyroid can cause diseases of the thyroid, as can nodules in the thyroid. Many patients are found to have thyroid nodules, yet their thyroid continues to work normally.
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Not all thyroid disease is cancerous. Most thyroid nodules and goiters are benign (~80%), as are both hypo- and hyperthyroidism.
If nodules are cancerous, and this is rare, the treatment varies by type. The most common types of thyroid cancer are called well-differentiated (papillary and follicular) and are generally treated with thyroid removal. Less common cancers of the thyroid are called medullary and anaplastic thyroid cancer, which may require more aggressive treatment.
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Hypothyroid disease can cause fatigue, weight gain, constipation, water retention, thinning hair, dry skin and difficulty concentrating.
Hyperthyroidism may be associated with anxiety, insomnia, tremors, weight loss, muscle weakness, excessive sweating and menstrual changes.
There is significant overlap in symptoms of thyroid hormone changes and it varies between patients.
Nodules, sometimes called goiter, may cause trouble swallowing, feeling of choking or pressure in the neck, or no symptoms at all.
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Both hypothyroidism and hyperthyroidism are more common in women.
Hypothyroidism is often seen in patients who have a personal history of autoimmune diseases, have had radioactive iodine treatment, have low iodine in their diets, or are taking certain medications such as lithium or amiodarone.
Hyperthyroidism is most common in patients with Graves’ disease, an autoimmune system problem that overstimulates the thyroid. One or more growths in the thyroid can also cause overproduction of thyroid hormone. These growths are called toxic multinodular goiter and toxic adenoma, but are far less common a cause than Graves’ disease.
Thyroid cancer, which is rare, can occur in men and women, depending on cancer type.
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We can test thyroid function by assessing levels of thyroid stimulating hormone (TSH) in the blood, specifically TSH not associated with proteins, but free-standing hormones. These tests are more accurate than measuring total hormone levels present in the blood. We can also test for the presence of antithyroid antibodies, as well as calcitonin.
Nodules can be diagnosed by ultrasound or fine needle aspiration biopsy, in which a sample of cells in the thyroid are removed and examined under a microscope.
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Hypothyroidism can be treated with a pill form of thyroid hormone.
Hyperthyroidism is usually treated first with Beta blockers to control the symptoms, followed by antithyroid medications to block excess thyroid hormone production. In many patients, it is necessary to provide other definitive treatments such as thyroidectomy. Removing the entire thyroid and starting thyroid replacement therapy offers the strongest results with only a <1% recurrence rate. Another treatment plan is called Radioiodine ablation (RAI). Patients are given a pill of radioactive iodine to destroy the thyroid cells and avoid surgery. However, RAI ablation may worsen hyperthyroid eye disease, if present. It does not remove large thyroid tumors and may require treatment.
Cancerous nodules may be treated by surgery, TSH suppression and potentially radioiodine treatment. “Traditional” types of chemotherapy and radiation therapy are rarely ever indicated in thyroid cancer.