Symptoms
Common side effects of radioactive iodine therapy include:
Neck pain or swelling: Tenderness in the thyroid area is common shortly after treatment.
Nausea and vomiting: This is usually mild and temporary.
Dry mouth: RAI can affect the salivary glands.
Taste changes: Metallic or altered taste sensations may occur.
Dry eyes: Similar to dry mouth, RAI can affect tear production.
Fatigue: Feeling tired or weak is frequent.
Hair thinning: Temporary hair loss is possible, but usually grows back.
Changes in menstruation: Women may experience irregular periods.
Infertility: Though usually not permanent, RAI can affect fertility in both men and women.
Hypothyroidism: An underactive thyroid, which requires lifelong thyroid hormone replacement.
Sialadenitis (inflammation of the salivary glands): Can cause pain and swelling in the cheeks.
Rare but serious side effects: Including bone marrow suppression, secondary cancers (very rare).
Causes
Radioactive iodine therapy is used to treat:
Hyperthyroidism (overactive thyroid): Conditions like Graves' disease and toxic nodular goiter. In these cases, the thyroid gland produces too much thyroid hormone.
Thyroid cancer: After surgical removal of the thyroid, RAI is used to eliminate any remaining thyroid cancer cells.
Medicine Used
The medicine used is radioactive iodine (RAI), specifically iodine-131 (I-131). It is administered orally, usually as a capsule or liquid. The dosage varies depending on the individual's condition, the size of the thyroid gland or cancer, and other factors.
Is Communicable
The condition being treated (hyperthyroidism or thyroid cancer) is not communicable. However, *following* RAI therapy, the patient will emit small amounts of radiation. While not considered highly contagious, precautions are necessary to minimize radiation exposure to others.
Precautions
Following RAI therapy, patients need to take precautions to minimize radiation exposure to others for a specified period (usually a few days to a couple of weeks). Specific instructions will be provided by the healthcare team, but generally include:
Distance: Maintaining a distance of at least 6 feet from others, especially pregnant women and children.
Hygiene: Frequent handwashing, especially after using the toilet.
Hydration: Drinking plenty of fluids to help flush the radioactive iodine from the body.
Separate utensils and towels: Avoid sharing these items.
Avoid close contact: Minimize kissing, hugging, or sexual contact.
Laundering clothes separately: Wash clothes separately from other household members.
Toilet flushing: Flush the toilet twice after each use.
Travel restrictions: Airport security may detect radiation. It is essential to inform airport security and show them your doctor's note explaining your recent treatment.
How long does an outbreak last?
This question does not apply to RAI therapy or the diseases it treats. There is no "outbreak" associated with hyperthyroidism, thyroid cancer, or RAI therapy. The "outbreak" would refer to the period the patient emits radioactivity after RAI. This period is determined by the RAI dosage and individual patient metabolism, and specific instructions are provided on a per-patient basis.
How is it diagnosed?
Hyperthyroidism: Diagnosed through blood tests (measuring TSH, T3, and T4 levels) and sometimes a radioactive iodine uptake scan.
Thyroid Cancer: Diagnosed through a physical examination, ultrasound, fine-needle aspiration biopsy of thyroid nodules, and sometimes blood tests (measuring thyroglobulin levels).
Checking Success of Therapy: Whole body scan after therapy
Timeline of Symptoms
During Treatment (Immediately After RAI Administration): Nausea, neck pain, salivary gland swelling, taste changes may start within the first few days.
Days to Weeks: Fatigue, dry mouth, dry eyes, and changes in menstruation may develop over the next few weeks.
Weeks to Months: Hair thinning, and changes in thyroid hormone levels can occur. Hypothyroidism may develop within a few weeks to several months after treatment.
Long-Term: Hypothyroidism, if it develops, requires lifelong thyroid hormone replacement. Very rarely, secondary cancers can develop years later.
Important Considerations
Pregnancy: Radioactive iodine is contraindicated during pregnancy. Women of childbearing age should undergo a pregnancy test before treatment. It's recommended to avoid pregnancy for 6-12 months after RAI therapy.
Breastfeeding: Radioactive iodine should not be administered to breastfeeding mothers. Breastfeeding should be stopped permanently before treatment.
Communication with healthcare provider: It's crucial to discuss all medications, supplements, and pre-existing medical conditions with the healthcare provider before RAI therapy.
Follow-up: Regular follow-up appointments with an endocrinologist are essential to monitor thyroid hormone levels and adjust medication as needed.
Long term effects: Be aware of possible side effects that can develop years later and discuss with your doctor.