Click here for Frequently Asked Questions on Thyroid Enlargement.
Growth or enlargement of the thyroid may be due to a number of different conditions. The majority of patients with thyroid enlargement have benign thyroid disease. In areas of iodine deficiency, thyroid growth, leading to large thyroid glands or 'goiters' is not uncommon. Defects in the function of the thyroid may lead to thyroid enlargement as the gland tries to compensate and maintain thyroid hormone production at normal levels. Inflammation of the thyroid, as may occur in Hashimoto's thyroiditis, may commonly lead to an enlarged thyroid. Similarly, development of one or more thyroid nodules may be associated with asymmetrical or generalized thyroid enlargement. Finally, thyroid cancer may also be detected as a cause of an enlarged thyroid gland.
It is quite clear that enlargement of the thyroid or the presence of nodules within the thyroid is common, particularly as revealed when sensitive imaging techniques such as ultrasound are used. In one population survey of over 96,000 persons carried out in Germany, abnormal findings (goiter and/or nodules > 0.5 cm) were observed in 33.1% of the examined patient population, as outlined in Prevalence of thyroid disorders in the working population of Germany: ultrasonography screening in 96,278 unselected employees. Thyroid. 2004 Nov;14(11):926-32.
Most patients with thyroid cancer that present with thyroid enlargement will have a thyroid nodule detected on clinical examination or ultrasound. Patients who have symmetrical and diffuse enlargement of the thyroid gland are less likely to have thyroid cancer. Symptoms such as difficulty breathing, neck pain, change in voice, choking, or trouble swallowing should prompt investigations that focus on whether an enlarged thyroid might be contributing to these symptoms. Similarly, patients with a rapidly enlarging thyroid gland (visible enlargement over days to weeks) should also have prompt investigations to determine the etiology or cause of the thyroid enlargement.
A sudden appearance of an enlarged thyroid does not always herald bad news. Many patients with sudden thyroid enlargement may have a small hemorrhage in the thyroid, leading to expansion and enlargement of the thyroid due to blood filling a nodule. Similarly, patients with thyroid inflammation, such as subacute thyroiditis, may also experience rapid enlargement of the thyroid, in association with symptoms of a viral illness (fever, malaise, neck pain etc). To differentiate among these possibilities, patients who have symptoms or who notice rapid thyroid enlargement should see their physician promptly for appropriate assessment and investigations.
In rare instances, a very large thyroid gland (goiter) can cause compression of local structures in the neck, such as the airway (trachea). If this problem continues to worsen, patients may experience shortness of breath, which can develop quite rapidly if damage to the trachea causes collapse of the airway. Patients with large goiters may need to have their airway examined, through the use of imaging studies such as a chest X-Ray, or preferably an airway echogram, MRI, or CT scan. If significant narrowing of the trachea is detected, treatment options include surgery, and less often, possibly radioactive iodine in patients who are not considered ideal surgical candidates.. Although many large goiters do not take up large amounts of radioactive iodine, recent evidence suggests that treatment of patients with high doses of radioactive iodine, often requiring admission to hospital, may be effective in producing some degree of reduction in goiter size. Furthermore, the diameter of the trachea may even increase over time. For an overview of a study examining treatment of large goiters with radioactive iodine, see J Clin Endocrinol Metab 1999 84:3636-41 The feasibility of high dose iodine 131 treatment as an alternative to surgery in patients with a very large goiter: effect on thyroid function and size and pulmonary function and Long-term effects of radioiodine on thyroid function, size and patient satisfaction in non-toxic diffuse goitre. Eur J Endocrinol. 2004 Apr;150(4):439-45.
How should my enlarged thyroid or goiter be treated?
The answer to this question depends on why your thyroid is enlarged, the size of your thyroid, whether there are multiple nodules or simply diffuse enlargement without nodules, the level of your TSH, and any co-existing illnesses and relevant medical history. Although treating patients with thyroxine therapy for years used to be viewed as highly effective to prevent further growth or even to induced a decrease in thyroid size, more recent studies have raised questions about this strategy. For some patients with enlargement of the thyroid, radioactive iodine treatment, even in the absence of hyperthyroidism, appears to be an effective alternative. See A Randomized Trial Comparing Levothyroxine with Radioactive Iodine in the Treatment of Sporadic Nontoxic Goiter. J Clin Endocrinol Metab. 2001 Mar 1;86(3):998-1005.
I have had an enlarged thyroid for years. Do I need to see a physician?
In general, it is probably wise to have an enlarged thyroid gland monitored on a regular basis. Potential problems to look out for include associated abnormalities in thyroid function, possible compression of local structures such as nerves, blood vessels and the trachea, and a risk of cancer. Accordingly, periodic assessments with attention to these issues should detect small problems before they become more difficult to treat.