1.How to treat hyperthyroidism
There are three main treatments for hyperthyroidism, including internal antithyroid drug (ATD) treatment, nuclear medicine iodine-131 treatment, and surgical treatment.
Internal ATD treatment is relatively mild, and the dosage can be adjusted in time during treatment. The disadvantage is that the treatment course is long, usually requiring 1-2 years of standardized treatment; during treatment, ATD can cause allergies, damage to liver and kidney function and the hematopoietic system and is often difficult to maintain once it occurs. Another shortcoming is that hyperthyroidism is prone to relapse when the drug is discontinued or reduced, and the relapse rate of ATD treatment has been reported to be around 40-60%.
Iodine-131 treatment is easy to use and usually only one dose of iodine-131 is given. The symptoms of hyperthyroidism start to improve about 4 weeks after treatment, and the remission rate of hyperthyroidism usually reaches 75-80% in about one year. Iodine-131 treatment does not cause allergy, damage to liver and kidney function or hematopoietic function. Those hyperthyroid patients with allergy, abnormal liver and kidney function or decreased blood cells due to ATD treatment can still be treated.
Some patients with no significant improvement in symptoms or incomplete remission after six months of iodine-131 treatment can be retreated with iodine-131 again. The disadvantage of iodine-131 treatment is that it is slow to relieve symptoms. Surgical treatment should be preferred for patients with hyperthyroidism with severe proptosis.
Surgical treatment is usually performed by subtotal thyroidectomy for hyperthyroidism, which provides rapid relief of hyperthyroidism, especially for patients with markedly enlarged thyroid gland with proptosis and hyperthyroidism with nodules, but it is traumatic and may cause surgical complications such as damage to the recurrent laryngeal nerve and hypoparathyroidism in some cases. Some patients still have recurrence of hyperthyroidism after surgery.
Generally, the chance of occurrence or hypothyroidism after iodine-131 treatment and surgery is higher than that of drug treatment.
2. Which type of hyperthyroidism is suitable for radioactive iodine-131 treatment?
Toxic diffuse goiter, especially hyperthyroidism can be treated with iodine-131 if the following conditions occur: abnormal liver function, hypocellularity unsuitable for antithyroid drug (ATD) treatment; allergy to ATD drugs; relapse after ATD treatment; relapse after surgery or unwillingness to operate.
Toxic nodular goiter with hyperthyroidism; chronic lymphocytic thyroiditis with hyperthyroidism; non-toxic goiter can also be treated with iodine-131 from cosmetic point of view.
3.What preparations should be made before iodine-131 treatment for hyperthyroidism?
Because iodine-containing foods, medications and antithyroid drugs have an effect on the uptake of iodine-131 by the thyroid gland, antithyroid drugs and iodine-containing foods and medications should be discontinued for at least 4-6 weeks prior to treatment. Symptomatic treatment of hyperthyroidism symptoms such as panic attacks, low white blood cells and abnormal liver function should be continued during discontinuation of medication.
4.What tests should be done before iodine-131 treatment for hyperthyroidism?
Before taking iodine-131 treatment, patients with hyperthyroidism should have their thyroid iodine-131 uptake rate measured, biochemical indicators of thyroid function such as TT3, TT4, FT3, FT4, TSH measured, thyroid antibodies such as A-Tg, A-TPO and TSH receptor antibodies (TRAb, TBII, etc.) measured, thyroid nuclear imaging or ultrasound examination to clarify the size of the thyroid gland and make preliminary judgments. The nature of the thyroid nodule, blood count, liver and kidney function, etc.
5.What is iodine-131? What are the medical uses?
Iodine-131 is a radioactive drug, an isotope of iodine, which decays by half every 8 days (half-life of 8 days); it emits gamma rays for imaging and beta rays for treatment to play a diagnostic and therapeutic role. Iodine-131 accumulates only in the thyroid tissue and is not taken up by other tissues. The beta rays emitted by iodine-131 have a range of only 2 mm in the thyroid gland ****, and the energy it releases can destroy the hyperfunctioning thyroid tissue and shrink the enlarged thyroid gland as if it had been operated on once, with minimal impact on the surrounding tissues.
Iodine-131 is mainly used for the treatment of hyperthyroidism such as hyperthyroidism and Plummer’s disease. It is also used for the determination of thyroid function, thyroid imaging, and the treatment and follow-up of well-differentiated thyroid cancer and its metastases.
6. Nuclear medicine examination of the thyroid is safe
The chemical amount of iodine-131 used in the determination of iodine uptake rate of thyroid gland is very small, and the chemical amount of radioactive dose of 2 microjuice is 1.6×10-11 grams, which has no effect and harm to human body.
The radioactive drug 99mTcO4-, which is commonly used for thyroid imaging, has a half-life of only 6 hours. The radioactive dose received by the patient is less than that of a single X-ray chest film. Iodine-131 can also be used for imaging, but only in special cases such as finding ectopic thyroid glands or finding metastases of thyroid cancer.
7. Can hyperthyroidism treated with iodine-131 cause hypothyroidism?
All three methods of hyperthyroidism treatment (anti-thyroid drugs, iodine-131 and surgery) can cause hypothyroidism. As long as hyperthyroidism is cured and does not recur, a certain percentage of hypothyroidism occurs every year. Therefore the occurrence of hypothyroidism is not caused by iodine-131 treatment.
The incidence of hypothyroidism due to hyperthyroidism treated with iodine-131 varies from hospital to hospital at home and abroad, but in China it is mostly 10-25%, and the trend is increasing year by year.
8.Iodine-131 can cure hyperthyroidism and you can still have children
After one year of iodine-131 treatment, hyperthyroidism symptoms are relieved and biochemical indicators of thyroid function return to normal, then you can get pregnant. Even if hypothyroidism occurs after hyperthyroidism treatment, those who have normal biochemical indicators of thyroid function through drug replacement therapy can also get pregnant.
9. Not all patients with hyperthyroidism are suitable for iodine-131 treatment.
Patients who are pregnant or breastfeeding and patients in the acute phase of acute myocardial infarction cannot be treated with iodine-131;
Iodine-131 therapy is also not suitable for patients with severe renal impairment, because all iodine-131 is excreted in the urine except for the uptake of iodine-131 by the thyroid gland. If the kidney function is poor, iodine-131 cannot be eliminated in the body in time, and iodine-131 accumulates in the body, especially in the kidney for a long time exposing the patient to unnecessary exposure.
Iodine-131 therapy is prohibited or used with caution in cases of extreme enlargement of the thyroid gland or retrosternal goiter with **** symptoms, because the oversized thyroid gland will aggravate **** symptoms due to mild inflammatory reaction when treated with iodine-131, resulting in respiratory difficulties for the patient.
10. Can anti-thyroid medication and iodine-131 therapy be used together for hyperthyroid patients?
Since antithyroid medication can affect the uptake of iodine-131 by the thyroid gland and the biochemical measurements of thyroid function, the patient should generally stop taking antithyroid medication (ATD) and abstain from iodine-containing food and medication for more than 4 weeks before undergoing the relevant nuclear medicine examination and treatment.
However, in patients with severe hyperthyroidism, because the general condition of the patient is poor and the therapeutic effect of iodine-131 is slow, in order to prevent the aggravation of the disease or the emergence of hyperthyroidism crisis, the drug is usually stopped only three days before the determination of the iodine absorption rate of the thyroid gland, and ATD treatment is continued after three days of iodine-131 until iodine-131 takes effect.
11. Can the proptosis disappear after Iodine-131 treatment?
Hyperthyroidism with proptosis may appear before the onset of hyperthyroidism, or during the treatment of hyperthyroidism, and in a few patients it may appear after the control of hyperthyroidism or even during hypothyroidism. There is no specific treatment for hyperthyroidism with proptosis. In general, most of the hyperthyroidism proptosis is reduced after Iodine-131 treatment, but in very few patients, the proptosis is still aggravated after the hyperthyroidism symptoms are controlled.
12.What should I do if I have low thyroid?
Once diagnosed, the treatment of hypothyroidism is relatively simple, using thyroid hormone replacement therapy to bring the patient’s thyroid hormone levels to normal. As the treatment only replenishes the patient’s body with insufficient thyroid hormone, as long as the body’s thyroid hormone level is adjusted to the normal range, it will not cause damage to the patient’s liver and kidney function and hematopoietic system; nor will it affect pregnancy and breastfeeding. It is just like buying food to eat when you cannot grow your own food. However, when heart disease is accompanied by low thyroid, it is necessary to start supplemental treatment from small doses.
13.Iodine-131 can also treat thyroid cancer
The thyroid gland is an endocrine organ in the body, which can produce thyroid hormones, and iodine is one of the substances used to synthesize thyroid hormones. Iodine-131 is an isotope of iodine, which has the same chemical properties as iodine, and can be selectively taken up by the thyroid gland after oral administration. Some functional thyroid cancers also have iodine uptake. These thyroid cancer cells are able to take up iodine after normal thyroid tissue has been expelled. Unlike ordinary iodine, iodine-131 emits rays that can effectively destroy tumor cells.
14.Not all thyroid cancers can be treated with iodine-131
Not all thyroid cancer patients can be treated with iodine-131. Some thyroid cancer cells have the function of normal thyroid gland and can take in iodine, so they can also take in iodine-131, so such patients can be treated with iodine-131. However, some thyroid cancer cells do not have the function of normal thyroid gland and cannot take in iodine, so they cannot take in iodine-131 and therefore cannot be treated with iodine-131.
15.Iodine-131 therapy is also needed for thyroid cancer patients after surgery
During the surgery, the physicians only judge whether the thyroid cancer has been removed or not according to the naked eye, or there may be a little residue in order to protect the surrounding normal tissues. At this time, if iodine-131 is applied, no matter where the cancer cells are, if they have the function of iodine uptake, iodine-131 will gather there to destroy the tumor cells. Therefore, it is necessary to apply iodine-131 treatment after surgery to reduce the possibility of local recurrence and prolong the survival period. And for metastatic lesions in other sites, as long as they have iodine uptake function, they can also be treated with iodine-131.
16.Iodine-131 treatment for thyroid cancer also has side effects
Due to the high dose of iodine-131 treatment, dry mouth, swelling and pain in the salivary gland area, swelling in the front of the neck, pain in the thyroid area and some digestive symptoms may occur in the early stage after the treatment, as well as a transient decrease in white blood cells and platelets, which can be relieved by symptomatic treatment by physicians. It is best to consider pregnancy only after one year of iodine-131 treatment.
17.What should the patient do before iodine-131 treatment for thyroid cancer?
Patients should stop taking thyroid tablets and T3 tablets and all iodine-containing drugs for 4-6 weeks before applying iodine-131 treatment under the guidance of physicians.
18.What do I need to pay attention to after iodine-131 treatment for thyroid cancer?
Due to the large dose of iodine-131 used for treatment, patients should stay in isolation ward for the first 3-5 days after taking the drug, and can be discharged after 3-5 days, but should not go to public places and try to avoid contact with pregnant women and children. After 3-6 months of iodine-131 treatment, the doctor can decide whether to repeat the treatment or choose other treatments according to the specific situation.
19.There are requirements for iodine-131 treatment for thyroid cancer patients after surgery
Iodine-131 therapy is not suitable for pregnant and lactating women, patients with laboratory tests showing WBC: 3.0×109/L, PLT: 90×109/L, severe liver and kidney dysfunction, and patients whose postoperative neck wound has not completely healed.