Thyroid nodules are usually benign (noncancerous) tumors which develop from thyroid cells are very common in clinical practice. Above the age of 60 thyroid nodules can be detected in at least 50% of the population. As long as nodules are small in size and located some distance from sensitive structures such as the trachea they are often asymptomatic. However, thyroid nodules can also cause symptoms such as shortness of breath or – in the case of hot nodules – hyperthyroidism (overproduction of thyroid hormones).
Several causes explain how nodules develop in the thyroid
There are several potential causes for the development of a lump in the thyroid. Whilst some are clearly defined and well-known, others are more uncertain:
- Iodine deficiency:
The thyroid requires iodine to fulfill its function and produce thyroid hormones. If there is not enough iodine available due to insufficient supplementation in diet, hormone production is impaired. In these cases, it is common for the thyroid to enlarge and develop nodules. Thus, supplementation through use of iodized salt has been recommended.
- Grave’s disease:
Grave’s disease is an autoimmune condition which occurs due to the immune system mistakenly attacking the thyroid. This causes the thyroid to become overactive and can lead to the development of hyperthyroidism (overactive thyroid). It is still not fully understood what causes the disease, however familiar history and smoking have been considered as potential risk factors.
What causes lumps in the thyroid?
Despite its rarity, inflammations of the thyroid is possible (also called thyroiditis). This can be caused by viral infection like the flu, mumps or an upper respiratory virus. Also, autoimmune disease can cause chronic inflammation of the thyroid also called Hashimoto’s thyroiditis. The condition can be painful and also cause a bumpy feeling of the thyroid.
Echotherapy for thyroid nodules
Further causes of thyroid nodules
Lumps in the thyroid are seldom malignant. Less than 5% of nodules turn out to be cancerous. Malignant nodules are often larger (4 cm or more), firm when touched and feel as if they are fixed to nearby structures. It is important to rule out the risk of cancer when a lump is diagnosed, which is why physicians may use several diagnostic tools in order to correctly classify a nodule.
- Other causes:
Most cases of thyroid nodules can not be traced back to a main cause. However, as women are more commonly diagnosed with nodules or thyroid enlargement, gender is expected to play a significant role. Also, often thyroid enlargements have been observed during pregnancy.