Thyroid nodules are overgrowths of thyroid cells that form a lump within the thyroid gland10. Nodules are common entities in the thyroid and most of the time, they are harmless and do not produce any symptoms. In fact, according to American Thyroid Association (ATA), only 40% of the patients with thyroid nodules exhibit some level of symptoms1. The precise cause of most thyroid nodules remains unknown. Today, we are going to cover some medical conditions that are associated with the development of thyroid nodules.
Risk Factors for Thyroid Nodules
- Gender: Women are more likely to have thyroid nodules than men. In fact, 1/8 of women will develop some form of thyroid disease during their lifetime1.
- Age: The likelihood of getting thyroid nodules increases as you age.
- Family History: Other family members with thyroid conditions increases your chance of getting thyroid disease.
- Radiation Exposure: Prior exposure to radiation from medical treatment to the head and neck area may increase your chance of developing nodules.
Medical Conditions That Can Cause Thyroid Nodules
The underlying cause of everyone’s thyroid nodule varies. Below are several conditions that are associated with nodular development in your thyroid gland.
Thyroid Hyperplasia (Goiter)
Diffuse thyroid hyperplasia is the enlargement of the thyroid gland due to an increase in the reproduction rate of the thyroid tissue. Enlargement of the thyroid gland is also known as goiter. Thyroid hyperplasia accounts for 80% of all nodular thyroid disease13. It has many causes including iodine deficiency and thyroid autoimmune diseases13. The goiter could result in:
- Hyperthyroid: overproduction of thyroid hormones
- Euthyroid: normal production of thyroid hormone
- Hypothyroid: underproduction of thyroid hormone
Thyroid adenomas are benign lesions (tumors) of the thyroid gland. They account for 5-10% of all nodular disease of the thyroid13. About less than 10% of thyroid adenomas are hyper-functional with the overproduction of thyroid hormone causing the nodules to be toxic (hyperthyroidism)13. The majority of thyroid adenoma functions normally, producing a normal level of thyroid hormone (euthyroid)13.
There are two autoimmune conditions that can predispose (cause) a thyroid gland to develop thyroid nodules: Hashimoto Disease and Grave’s Disease. Both conditions can associate with goiter as a result of an underactive or overactive thyroid.
Hashimoto Disease is an autoimmune disorder in which the immune system produces antibodies that attack the thyroid gland causing inflammation (thyroiditis). As a result, the ability of the thyroid gland to produce hormones becomes reduced and this leads to a condition called hypothyroidism. In an average person, thyroid hormones T3 and T4 are required for many vital bodily functions such as metabolism. Hence, reduced production of thyroid hormones slows down many bodily functions, causing a range of undesired symptoms that are associated with the body having too little energy.
Grave’s Disease is another autoimmune disease where the body’s immune system attacks the thyroid gland causing overproduction of the thyroid hormone. This condition is known as hyperthyroidism. Increased thyroid hormone production causes symptoms that are associated with the body having too much energy.
Lastly, malignancy (cancer) is the most unwanted cause for any thyroid nodules, and they occur in 5-10% of all thyroid nodules<sup>12</sup>. There are several types of thyroid cancer including Papillary Cancer (PTC), Follicular Cancer (FTC), Medullary Cancer (MTC), and Anaplastic Cancer (ATC). Most thyroid cancers respond well to treatment with a good prognosis rate, though some very rare thyroid cancer can be aggressive13.
Thyroid nodules are very common entities and according to ATA, about 20 million Americans have some form of thyroid diseases1. Fortunately, most thyroid nodules are asymptomatic and benign. To learn more about your thyroid issues, speak to a specialist today!
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