Surgical or radio-iodine treatment in thyrotoxicosis

Indications for radioiodine treatment include:

• radio-iodine treatment
  • can be used as the first-line treatment for adults with Graves' disease, toxic adenoma, and toxic multinodular goitre.
    • should be considered as the preferred treatment for those
      • with severe Graves’ disease, especially young patients aged less than 40 years, men, and those with a large goitre
      • who are unlikely to achieve long term remission with antithyroid drugs
  • early use of radioiodine has been shown to be the cheapest long term strategy in managing Graves’ disease
  • a pragmatic fixed dose that results in euthryoidism or hypothyroidism in 70-90% of patients is recommended
  • treatment with optimal individual dose of radioiodine does not improve outcome
  • doses of 370 to 550 MBq for routine use in Graves’ disease is used in the UK (large goitres may need higher doses)
  • regular thyroid function tests should be carried out to detect radioiodine induced hypothyroidism early
  • release of preformed hormone may lead exacerbation of thyrotoxicosis (or even a thyroid storm being precipitated)
    • pre-treatment with thionamides (until euthyroid) is recommended to reduce the risk in patients with large goitres, severe thyrotoxicosis, ischaemic heart disease, heart failure, or arrhythmia
  • optimal outcome from radioiodine can be obtained by stopping methimazole or carbimazole at least a week before radioiodine therapy
    • if propylthiouracil is used, it should be stopped at least two weeks before radioiodine
  • absolute contraindications include:
    • pregnancy
    • breastfeeding
    • planning pregnancy
    • inability to comply with radiation safety recommendations
  • if biopsy of thyroid nodules indicates or are suspicious for cancer, radioiodine treatment is contraindicated
  • women of child-bearing age are advised to avoid pregnancy for six months after receiving radio-iodine treatment
  • the presence of Graves' ophthalmopathy is a relative contra-indication to radio-iodine therapy because it may deteriorate after radio-iodine treatment (1,2)

Thyroidectomy is the most effective and predictable treatment for Graves’ disease

• total thyroidectomy is preferred over subtotal thyroidectomy since the frequency of successful outcomes are significantly higher in the former with no differences in the rate of complications
• especially recommended for the following patients:
  • large goitres (cosmetically undesirable) or low uptake of radioactive iodine (or both)
  • suspected or documented thyroid cancer
  • moderate-to-severe ophthalmopathy, for which radioactive iodine therapy is contraindicated
  • a preference for surgery
• patients need to be rendered euthyroid before surgery
  • if thionamide antithyroid drugs cannot be used, treatment with iodine loading with potassium iodide, Lugol’s iodine, or oral cholecystographic contrast media (iopanoic acid 1 g daily) for 5-10 days will result in euthyroidism in almost all cases (1,2)

Reference:

• (1) Vaidya B, Pearce SH. Diagnosis and management of thyrotoxicosis. BMJ. 2014;349:g5128
• (2) De Leo S, Lee SY, Braverman LE. Hyperthyroidism. Lancet (London, England). 2016;388(10047):906-918.