1. What is the principle of radioactive iodine treatment for hyperthyroidism?
Radioactive 131 iodine was first used as a treatment for hyperthyroidism in 1942, and it is an effective anti-thyroid drug. Thyroid cells have a special affinity for iodide, and after a certain amount of 131 iodine is taken orally, it can be absorbed by the thyroid gland in large quantities, and the radioactive 131 iodine with damaging effects can be seeded into the thyroid tissue. 131 iodine, when decaying into 131 xenon, can radiate beta rays (99%) and gamma rays (1%). The former has an effective range of only 0.5 to 2 mm and can selectively destroy the thyroid follicular epithelium without affecting the adjacent tissues. The thyroid tissue can be irradiated for a long time in a concentrated manner, and its gland is gradually necrotic after being destroyed and replaced by non-functional connective tissue, thus reducing the secretory function of the thyroid gland and enabling hyperthyroidism to be cured, achieving a purpose similar to subtotal thyroidectomy. Therefore, some people call 131 iodine treatment for hyperthyroidism as “internal thyroid surgery”.
2.What are the indications for radioactive iodine treatment of hyperthyroidism?
Patients with hyperthyroidism who meet one of the following conditions can be treated with radioactive 131 iodine.
① Diffuse goiter with hyperfunction.
② Combined with serious organic pathology, such as heart disease, chronic nephritis, hypertension, hepatic steatosis, chronic bronchitis, severe diabetes mellitus, mental disorders and neurological disorders.
Patients with severe diabetes mellitus, mental disorders and organic lesions of the nervous system.
(3) Patients with poor results of long-term anti-thyroid medication, multiple relapses, or those who are allergic to medication and should not be treated with medication.
④ Patients with hyperthyroidism with leukocytopenia or thrombocytopenia.
⑤ Patients with hyperthyroidism with atrial fibrillation.
(6) Patients who have already undergone thyroidectomy and have relapsed; because there is a greater risk of injury to the recurrent laryngeal nerve or parathyroid glands during reoperation.
Patients who are not willing to undergo surgery or are not suitable for surgery.
(7) Patients with severe proptosis (most proptosis is reduced after 131 iodine treatment).
(8) Patients with hyperthyroidism combined with chronic lymphatic thyroiditis who have an increased rate of I131 uptake.
3.What preparations should be made before radioactive iodine treatment for hyperthyroidism?
The following preparations should be made in advance for the treatment of hyperthyroidism with radioactive iodine.
①It is advisable to avoid iodine and other iodine-containing foods or drugs 2 to 4 weeks before taking 131 iodine.
②If your condition is severe before 131 iodine treatment, with heart rate exceeding 160 beats per minute, or if your condition is severe, you should first be treated with anti-thyroid medication or benzos.
or “Tretinoin”, etc., and then use 131 iodine only after the symptoms have been reduced.
Patients using antithyroid drugs should stop taking them, for example, 3-5 days for tabazol and 2 weeks for propylthiouracil.
Then the 131 iodine uptake rate should be measured, followed by 131 iodine treatment.
④ Routine blood and urine tests should be performed to understand the function of the major organs.
⑤ Perform thyroid uptake rate or thyroid scan to calculate the drug dose.
⑥Explain to the patient the precautions related to 131 iodine treatment.
⑦For a few days before and after taking 131 iodine, the patient should rest in bed and avoid strenuous activities.
4.What is the effect of radioactive iodine treatment for hyperthyroidism?
If the patient and the doctor cooperate with each other, the efficiency of 131 iodine treatment for hyperthyroidism is more than 90%. After taking the drug, the effect will appear in 3 to 4 weeks, followed by month by month symptom reduction, thyroid gland shrinkage and weight gain, and most patients can reach normal thyroid function in 3 to 4 months. In some cases, it takes 6 months to a year to achieve remission. About 2/3 of cases can be cured in one treatment, while 1/3 of cases require 2 or more treatments. Generally, about 50% to 80% of patients are cured in one course of treatment, and about 20% to 40% are cured in two courses of treatment, and few patients need a third course of treatment. Therefore, patients with hyperthyroidism treated with 131 iodine should not just drink the medicine and leave, but should go to the doctor for follow-up, follow up and observation at regular intervals to adjust or decide the next treatment plan.
5.What should I pay attention to after taking 131 iodine?
In order to obtain the best therapeutic effect, the following aspects must be noted after taking the drug.
①Eat only after taking 131 iodine on an empty stomach for 2 hours to avoid affecting the absorption of iodine.
②After taking 131 iodine, the therapeutic effect usually begins to appear after 3 weeks, a period before the clinical symptoms start to improve.
It is not advisable to use iodine, bromine and anti-thyroid drugs arbitrarily before the clinical symptoms start to improve, in order not to affect the reabsorption of 131 iodine and reduce the therapeutic effect. For one month after treatment
(2) Within one month after treatment, eat a low iodine diet and do not eat sea plants such as seaweed and seaweed.
③Patients should take rest, avoid strenuous activities and mental stimulation, and prevent infections for two weeks after taking the medication.
④Since symptoms of radiation thyroiditis such as itching and pain in the neck can be seen in the early stage of receiving 131 iodine treatment, during the first week after treatment
Avoid looking at or squeezing the thyroid gland for the first week after treatment.
⑤ Remember the contact number of your doctor so that you can contact him or her at any time if you have any questions.
6) Follow the doctor’s instructions and go to the hospital regularly for follow-up.
6.What are the early toxic reactions of radioactive iodine treatment for hyperthyroidism?
The treatment of hyperthyroidism with 131 iodine is simple and effective, and most of them have no adverse effects. Adverse reactions are generally divided into two types: early toxic reactions and late complications. Early toxic reactions refer to reactions that occur within 2 weeks after taking the drug, and are commonly seen as follows.
① Systemic reactions are often dominated by digestive system symptoms, such as anorexia, nausea, vomiting, etc. A few have skin pruritus, rash, dizziness, malaise, etc., which can disappear in 2 to 3 days with symptomatic treatment.
②Local reactions are more common, mainly the manifestation of thyroid edema and radiation thyroiditis. Patients have itching in the neck, swelling and pressure, and even pain in the lower throat and cough, which do not require special treatment and gradually disappear after a few days or 1 week.
(3) During the first 2 weeks of treatment, some patients may experience increased symptoms (elevated basal metabolic rate and serum protein-bound iodine concentration), which can gradually improve with bed rest or application of some sedatives and some beta-blockers such as benzodiazepines. Individual serious patients may develop hyperthyroid crisis, manifested as mental agitation, high fever, sweating, accelerated heart rate (often above 140 beats/min), increased pulse pressure, and even atrial fibrillation, diarrhea and coma, etc., which can often be life-threatening if not treated in time. This is due to the destruction of thyroid follicles by radioactive damage and the release of large amounts of thyroxine into the blood or other factors. For patients with severe clinical symptoms and a large thyroid gland, thioureas should be administered before 131 iodine is given and should be closely monitored when 131 iodine is given.
④ Leukopenia, which mostly occurs after a 131 iodine injection, can be gradually recovered.
7.What should be done for hypothyroidism after radioactive iodine treatment?
Hypothyroidism is very simple to treat, and can be easily corrected by giving thyroxine tablets or eugenol.
Hypothyroidism is one of the complications of 131 iodine treatment, and most of them occur between 2 and 6 months after treatment, but some occur later or several years later. The incidence of hypothyroidism after 131 iodine therapy varies between domestic and foreign reports, but increases gradually with time. ～The incidence of hypothyroidism was reported to be 2-3% per year after 131 iodine treatment, which is related to the natural failure of thyroid disease itself, resulting in the gradual development of hypothyroidism with increasing age. Currently, with the advanced scientific methods of detection and treatment, the incidence of hypothyroidism is generally low. Possible reasons for the occurrence of hypothyroidism: first, natural decay of thyroid disease itself leading to gradual development of hypothyroidism with age; second, damage to the nucleus of thyroid epithelial cells by ionizing radiation so that they cannot divide and regenerate, and hypothyroidism; third, related to the autoimmune response. How to reduce the occurrence of hypothyroidism after 131 iodine treatment is still a problem that has yet to be solved.
8.What are the pros and cons of low thyroid treatment?
Once hypothyroidism is diagnosed, its treatment is relatively simple, using thyroid hormone replacement therapy, the patient’s thyroid hormone level can be adjusted to normal, because 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, will not cause damage to the patient’s liver and kidney function and hematopoietic system; also will not affect pregnancy and breastfeeding. However, if heart disease is accompanied by hypothyroidism, supplemental treatment should be started from small doses.
9. Can radioactive iodine treatment for hyperthyroidism aggravate proptosis?
Severe progressive proptosis can occur spontaneously or after subtotal thyroidectomy, but less frequently after 131 iodine treatment. 131 iodine can improve proptosis in most patients (reported to be about 70%) after treatment, and only in a few cases can proptosis worsen. It is generally believed that 131 iodine can gradually reduce the function of the thyroid gland, so that the thyrotropin or proptosis-producing substances in the pituitary gland do not increase suddenly.
10. Can radioactive iodine therapy for hyperthyroidism cause cancer?
After a long time and a lot of clinical research, medical experts have observed that the incidence of leukemia and thyroid cancer does not increase compared with the natural incidence of these two diseases. One group of data showed that the incidence of thyroid cancer was 0.5% in 22714 cases of 131 iodine treatment group, 0.5% in 11732 cases of surgery group, and 0.3% in 1238 cases of anti-thyroid drugs. According to domestic statistics, among nearly 60,000 cases of hyperthyroidism treated with 131 iodine, only 2 cases of leukemia were reported, and their incidence was not higher than the natural incidence of the general population. From the perspective of medical development in the world, 131 iodine has been listed as one of the most effective methods for treating hyperthyroidism in textbooks around the world, therefore, 131 iodine treatment for hyperthyroidism is safe.