Medical Care
Nontoxic goiters usually grow very slowly over decades without causing symptoms. Without evidence of rapid growth, obstructive symptoms (eg, dysphagia, stridor, cough, shortness of breath), or thyrotoxicosis, no treatment is necessary. Therapy is considered if growth of the entire goiter or a specific nodule is present, especially if intrathoracic extension of the goiter, compressive symptoms, or thyrotoxicosis exists. The intrathoracic extension of the goiter cannot be assessed by palpation or biopsy. The goiter, if significant in size, should be removed surgically. The currently available therapies include thyroidectomy, radioactive iodine therapy, and levothyroxine (L-thyroxine or T4) therapy.
Radioactive iodine therapy: Radioiodine therapy of nontoxic goiters is often performed in Europe. It is a reasonable therapeutic option, particularly in patients who are older or have a contraindication to surgery.
Radioactive iodine therapy for nontoxic goiters was reintroduced in the 1990s. Careful studies have shown a reduction in thyroid volume in nearly all patients after a single dose of therapy.
Of patients with nontoxic diffuse goiter, 90% have an average of 50-60% reduction in goiter volume after 12-18 months, with a reduction in compressive symptoms. The decrease in goiter size positively correlated with the dose of iodine I 131 (131I). Reduction in size of goiter is greater in younger patients, those with only a short history of goiter, and in those with a small goiter. Baseline TSH is not a predictor of response to radioactive iodine.
Obstructive symptoms improved in most patients who received radioactive iodine.
Adverse effects, including thyroiditis, occurred, but no patient reported worsening of compressive symptoms requiring treatment. No long-term follow-up of patients treated by radioactive iodine exists. Patients after 131I therapy should always be clinically monitored for evidence of goiter regrowth.
Transient hyperthyroidism is rare and typically occurs in the first 2 weeks after treatment.
Unlike with treating hyperthyroidism with radioactive iodine, only a small percentage of patients develop hypothyroidism after radioactive iodine for nontoxic goiter.
Recombinant human TSH (rhTSH) may have a role in treating nontoxic goiter with radioactive iodine. Pretreatment with rhTSH 24 hours prior to therapy can result in needing smaller doses of radioiodine to shrink the goiter (up to 50% reduction).
Thyroid hormone suppressive therapy: The use of T4 in a euthyroid individual to shrink a nontoxic goiter is controversial.
One study showed that T4 therapy for nontoxic goiter reduced thyroid volume in 58% of patients compared with 4% reduction in patients treated with a placebo. However, these results have not been reproducible, and the benefit of using T4 needs to be weighed against the risk of the resultant subclinical hyperthyroidism that is associated with an increased risk of decreased bone mineral density and increased atrial fibrillation.
Goiter growth typically resumes after cessation of T4 therapy.
Surgical Care
Thyroidectomy or surgical decompression causes rapid relief for obstructive symptoms (see Image 3).
Most intrathoracic goiters may be removed from a cervical incision without sternotomy. Performing bilateral subtotal thyroidectomy is recommended to reduce the risk of continued goiter growth. The rate of goiter recurrence depends on the extent of surgery but should not be higher than 10% in 10 years.
After bilateral subtotal thyroidectomy, all patients require thyroid hormone replacement therapy. The full replacement therapy should start immediately after surgery, with TSH levels checked 3-4 weeks postoperatively. Adjust thyroid hormone therapy, such as T4, to maintain a TSH level in the reference range. Some evidence exists that thyroid hormone replacement therapy prevents recurrence of nontoxic goiter after surgical removal.
Consultations
Consult an endocrinologist in the complicated nontoxic goiter with nodule formation or obstructive symptoms.
If a high index of suspicion for malignancy exists in a patient with previous radiation exposure as a child, hoarseness, and lymphadenopathy, consult a thyroid surgeon.
Diet
Diets low in iodine need supplementation, especially in developing countries where government-supported iodine supplementation is not available. Patients taking iodine supplements may need a reduction to avoid iodine-induced thyroid disease in predisposed individuals.