Click here for Frequently Asked Questions on a Toxic Multinodular Goiter.

A multinodular goiter is simply a thyroid gland that is usually enlarged and contains multiple thyroid nodules. The nodules can be very small, often only a few millimeters in size, or the nodules can be larger, perhaps several cm each. There are generally two questions that need to be answered in patients with a multinodular goiter. The first question is usually: are all the nodules benign? The approach to this question depends on the clinical presentation, associated risk factors, the size of the nodules, and whether the nodules are functioning or non-functioning.

Non-functioning or cold nodules within a multinodular gland generally carry the same risk of malignancy as a single isolated cold nodule (10-15% risk of thyroid cancer) and need to be approached diagnostically in a similar manner akin to the investigation of an isolated single cold nodule.

The second question that needs to be answered relates to ascertainment of thyroid function in patients with a multinodular gland, as these patients often exhibit mild to moderate degrees of hyperthyroidism.

If treatment of a multinodular goiter is indicated, radioactive iodine or surgery is generally more effective in achieving a long-lasting solution to the problem compared to the use of medications alone. Although the hyperthyroidism may be treated initially with antithyroid medications, these medications will not usually achieve a permanent remission in patients with a multinodular goiter and hyperthyroidism.

Many patients with a toxic goiter may not have elevated levels of radioactive iodine uptake, rendering treatment with this modality challenging. It may be possible to use recombinant TSH to stimulate radioactive iodine uptake in this subgroup of patients, although it is not yet formally approved for this indication. See Effect of various doses of recombinant human thyrotropin on the thyroid radioactive iodine uptake and serum levels of thyroid hormones and thyroglobulin in normal subjects. J Clin Endocrinol Metab. 2001 Apr;86(4):1660-4.

Furthermore, current research protocols are assessing whether lower doses of Recombinant TSH, perhaps 0.03mg, can be used as an adjunct to increase iodine uptake during treatment of toxic goitre as described in Low-dose recombinant human thyrotropin-aided radioiodine treatment of large, multinodular goiters in elderly patients. Eur J Endocrinol. 2006 Feb;154(2):243-52 and Stimulation with 0.3-mg recombinant human thyrotropin prior to iodine 131 therapy to improve the size reduction of benign nontoxic nodular goiter: a prospective randomized double-blind trial. Arch Intern Med. 2006 Jul 24;166(14):1476-82. and Stimulation with 0.3-mg recombinant human thyrotropin prior to iodine 131 therapy to improve the size reduction of benign nontoxic nodular goiter: a prospective randomized double-blind trial. Arch Intern Med. 2006 Jul 24;166(14):1476-82

FAQs

My Free T4 is normal, my TSH is low, and I feel fine, yet my physician wants to treat me with radioactive iodine. Why?

The answer to this question depends on the age of the patient, the size of the gland, the associated medical conditions that may be present, the extent of hyperthyroidism, and this issue needs to be discussed carefully between physician and patient. In some instances, particularly in older individuals or in the potential setting of heart disease, it is sometimes advisable to treat a patient before an obvious clinical problem becomes apparent, such as the development of an unstable and rapid heart rhythm.

I have a large goitre and borderline high levels of thyroid hormones (mild hyperthyroidism). What are the treatment options?

Traditionally, treatment of patients with large multinodular goitres may include surgery, or radioactive iodine. Not all patients with large goitres have sufficient iodine uptake to allow for effective therapy with radioactive iodine. In some instances, adjuvant use of low dose recombinant TSH may increase iodine uptake in the thyroid and allow for more efficient treatment with radioactive iodine, as described in Low-dose recombinant human thyrotropin-aided radioiodine treatment of large, multinodular goiters in elderly patients. Eur J Endocrinol. 2006 Feb;154(2):243-52

Is there any risk to treatment of a multinodular goitre with radioactive iodine?

Patients may experience some degree of neck discomfort and swelling in the region of the thyroid gland following radioactive iodine. Furthermore, destruction of thyroid tissue is often associated with transient worsening of the hyperthyroidism for a few weeks, and in elderly subjects with a history of heart disease, this can be a serious issue. There is some evidence that older subjects treated with radioactive iodine may have an increased risk of mortality, but not if the treatment is sufficiently effective so as to induce hypothyroidism Increased cardiovascular and cancer mortality after radioiodine treatment for hyperthyroidism. J Clin Endocrinol Metab. 2007 Mar 20; [Epub ahead of print]