From the Guidelines
For mildly elevated serum iodine levels, the most appropriate initial step is to confirm the finding with repeat testing and assess for symptoms of iodine excess, as there is no direct evidence that treatment based on risk level alters final health outcomes 1. When evaluating a person with mildly elevated serum iodine levels, it is crucial to consider the potential sources of excess iodine, which may include iodine-rich foods, iodinated contrast media, certain medications, or topical antiseptics containing iodine.
- Key considerations include:
- Confirming the elevated iodine level with repeat testing to rule out laboratory error
- Assessing for symptoms of iodine excess, such as metallic taste, mouth sores, or signs of thyroid dysfunction
- Identifying and eliminating potential sources of excess iodine
- Monitoring thyroid function with TSH, free T4, and free T3 tests, as excess iodine can cause either hyperthyroidism or hypothyroidism depending on the underlying thyroid status Given the lack of direct evidence that treatment of thyroid dysfunction based on risk level alters final health outcomes, as noted by the USPSTF 1, the approach should focus on reducing dietary iodine intake and monitoring for any adverse effects on thyroid function.
- Recommendations for reducing iodine intake include:
- Limiting consumption of iodized salt, seafood, and dairy products
- Avoiding iodine supplements
- Considering endocrinology referral if symptoms are present or levels remain elevated despite dietary changes It is essential to prioritize the patient's morbidity, mortality, and quality of life when managing mildly elevated serum iodine levels, and most cases of mild iodine excess are expected to resolve with dietary modification alone, given the kidneys' efficient excretion of excess iodine 1.
From the Research
Management of Mildly Elevated Serum Iodine Levels
- The patient's condition may be related to excess iodine intake, which can cause hyperthyroidism, hypothyroidism, goiter, and/or thyroid autoimmunity 2.
- A thorough nutritional history is necessary to identify potential sources of excess iodine intake, such as overiodized salt, drinking water, animal milk rich in iodine, certain seaweeds, and iodine-containing dietary supplements 2, 3.
- The median urinary iodine concentration (UIC) can accurately identify populations with excessive iodine intakes, and thyroglobulin can also be used as a biomarker to assess iodine intake 2.
- In cases of iodine-induced thyrotoxicosis, a trial of corticosteroids may be utilized in the management, which can delay or prevent surgical management 4.
- It is essential to monitor and adjust iodine intake in the population to prevent thyroid disorders, and optimal iodine intake should be kept within a relatively narrow interval where iodine deficiency disorders are prevented, but not higher 3.
Potential Treatment Options
- Antithyroid drugs, such as methimazole, can be used to treat hyperthyroidism, and combining methimazole with inorganic iodine may be an effective regimen for moderate to severe hyperthyroidism 5.
- Radioactive iodine ablation and surgery are also treatment options for overt hyperthyroidism from autonomous thyroid nodules or Graves disease 6.
- Treatment choices should be individualized and patient-centered, and patients with subclinical hyperthyroidism may require treatment if they are at high risk of osteoporosis and cardiovascular disease 6.