Iodine-induced hyperthyroidism in a patient with a normal thyroid gland

Area of Science:

• Endocrinology
• Toxicology
• Nutritional Science

Background:

• Iodine is essential for thyroid hormone synthesis.
• Excessive iodine intake can disrupt thyroid function, leading to hyperthyroidism.
• Seaweed supplements are a potential source of high iodine content.

Observation:

• A 72-year-old female presented with symptoms and laboratory findings indicative of hyperthyroidism.
• The patient was ingesting over-the-counter sea-kelp (Vitalia) tablets.
• No pre-existing thyroid disease was identified in the patient.

Findings:

• Ingestion of sea-kelp tablets was associated with the development of iodine-induced hyperthyroidism.
• Discontinuation of the sea-kelp supplements led to the resolution of hyperthyroid symptoms and laboratory abnormalities.
• Thyroid function normalized within six months after cessation of iodine supplementation.

Implications:

• Seaweed-based supplements can pose a risk for inducing hyperthyroidism, even in individuals without prior thyroid conditions.
• Healthcare providers should inquire about supplement use, including herbal remedies, when evaluating patients with hyperthyroidism.
• Patient education regarding the potential risks of high-iodine supplements is crucial for preventing iatrogenic thyroid dysfunction.