What is the management of a patient with a history of toxic nodular goitre (TNG) who is non-adherent to anti-thyroid medication, presenting with palpitations and tachycardia, and a Thyroid-Stimulating Hormone (TSH) level of 0.2?

Management of Toxic Nodular Goiter with Poor Medication Adherence

Radioactive iodine therapy (RAI) is the most appropriate management for this patient with toxic nodular goiter who has demonstrated poor adherence to antithyroid medications and is presenting with symptomatic hyperthyroidism.

Clinical Assessment

The patient presents with:

• History of toxic nodular goiter
• Poor adherence to antithyroid medication
• Current symptoms of palpitations and tachycardia
• Suppressed TSH (0.2), indicating persistent hyperthyroidism

Treatment Options Analysis

Antithyroid Drugs (Option C)

• While antithyroid drugs like methimazole are indicated for toxic multinodular goiter 1, they are not effective in this case due to:
  • Documented poor medication adherence
  • Long-term studies show antithyroid treatment is not safe in patients with toxic nodular hyperthyroidism, primarily due to poor compliance 2
  • High relapse rates even with continued therapy (multiple relapses reported in follow-up studies) 2

Radioactive Iodine Therapy (Option D)

• RAI is highly effective for toxic nodular goiter:
  • Success rates of 83-89% in reversing hyperthyroidism 3, 4
  • Particularly effective in geriatric patients with toxic nodular goiter (83% response rate) 4
  • Considered first-line treatment for toxic nodular goiter in patients with poor medication adherence 2, 5
  • Higher doses of RAI (325-1000 MBq) show better outcomes than lower doses, with fewer persistent hyperthyroid cases (16.7% vs 50%) 2

Surgical Options (Options A & B)

• Total or near-total thyroidectomy:
  • Effective treatment with high cure rates (93%) 3
  • However, surgical intervention carries risks of complications including recurrent laryngeal nerve damage and hypoparathyroidism
  • Requires good perioperative control of hyperthyroidism, which is challenging in a non-adherent patient
  • Surgery is typically reserved for patients with large goiters causing compressive symptoms, suspected malignancy, or failure of other treatments

Management Algorithm

1. First-line treatment: Radioactive Iodine Therapy (RAI)

   • Preferred for toxic nodular goiter with poor medication adherence 2, 5
   • Higher doses (325-1000 MBq) are recommended for better efficacy 2, 6

2. Pre-RAI preparation:

   • Short-term antithyroid medication with close monitoring to normalize thyroid function before RAI
   • Beta-blockers (preferably with alpha-blocking capacity) to control symptoms of tachycardia and palpitations 7
   • Discontinue antithyroid drugs 3-5 days before RAI administration

3. Post-RAI follow-up:

   • Monitor thyroid function every 4-6 weeks initially
   • Approximately 58-64% of patients will require levothyroxine supplementation after RAI 3
   • Some patients (approximately 17%) may require a second RAI dose if hyperthyroidism persists 4

Important Considerations

• RAI therapy has a lower risk of post-treatment hypothyroidism compared to surgery, though both eventually lead to similar rates of hypothyroidism long-term 3
• RAI allows for outpatient treatment without the risks associated with surgery and anesthesia
• RAI is particularly suitable for patients with poor medication adherence as it requires only a single or few administrations rather than daily medication 2, 6
• Contraindications for RAI include pregnancy, lactation, and suspected thyroid malignancy 5

Conclusion

For this patient with toxic nodular goiter, poor medication adherence, and symptomatic hyperthyroidism (palpitations and tachycardia), radioactive iodine therapy (Option D) is the most appropriate management strategy, offering the best balance of efficacy, safety, and convenience given the patient's demonstrated inability to adhere to daily medication regimens.