1. What should I pay attention to in my diet for patients with hyperthyroidism (hyperthyroidism for short)?
Hyperthyroidism patients should not use iodized salt. It is recommended that they consume non-iodized salt, and foods with high iodine content should not be consumed, including kelp, seaweed, seafood such as sea cucumber, jellyfish, sea shells and sea fish such as salmon. When visiting the hospital, you should actively tell your doctor that you are a hyperthyroid patient, and remind him/her to avoid applying iodine-containing contrast agents when taking imaging and iodine-containing drugs such as amiodarone when treating cardiac arrhythmias, in order to avoid the recurrence of hyperthyroidism.
2. Can hyperthyroidism be stopped after drug treatment?
The most common cause of hyperthyroidism is an autoimmune disorder called Graves’ disease (also known as diffuse goiter with hyperthyroidism), which accounts for about 85% of hyperthyroidism. This disease is caused by the production of autoantibodies (TRAb) against a protein in the thyroid tissue: the thyrotropin receptor, which increases the production of thyroid hormones by the thyroid gland and leads to hyperthyroidism. It is generally recommended to apply hyperthyroidism medication and to consider stopping it after a year and a half of well-controlled hyperthyroidism symptoms. However, since there may be different subclasses of hyperthyroidism and their prognosis may be different, it is recommended that patients whose causative stimulating antibodies (TRAb) are still high after hyperthyroidism is controlled should not discontinue medication. Since current medications for hyperthyroidism are designed to reduce thyroid hormone synthesis without controlling the production of this stimulating antibody, most hyperthyroid patients, therefore, tend to relapse after stopping medication. It is recommended that most patients with hyperthyroidism need long-term maintenance treatment with small doses of medication.
3. Is iodine 131 isotope therapy the preferred treatment option for hyperthyroidism?
Iodine 131 isotope therapy is one of the three main treatment options for hyperthyroidism and is accepted by patients and physicians because of its simplicity and effectiveness. However, the biggest problem with this treatment method is that the chance of developing hyperthyroidism increases with time after treatment. The incidence of hypothyroidism has been reported to be as high as 50-80% after 10 years of treatment. And in some of the patients with Graves’, the natural course of its disease will slowly turn into hypothyroidism, therefore, it is not appropriate to apply iodine 131 isotope therapy to such patients with Graves’.
4. How to choose the medication to control hyperthyroidism in women who are pregnant?
There are 2 commonly used medications to treat hyperthyroidism: methimazole (MMI) and propylthiouracil (PTU). Since MMI has been reported to cause fetal developmental malformations, mainly skin dysplasia and “methimazole-related embryopathy”, including atresia of the posterior nasal aperture and esophageal duct, and facial malformations, it is recommended that you take these medications when planning a pregnancy and if you are pregnant. However, the US Food and Drug Administration has recently reported that PTU may cause liver damage and even acute liver failure, so it is recommended to closely monitor liver function when applying PTU therapy. Since drugs used to treat hyperthyroidism can enter the fetus partly through the placenta and have adverse effects on the fetus, the principle of treatment is to apply the smallest dose of drugs to achieve its hyperthyroidism treatment purpose. It is generally appropriate to keep the concentration of free thyroxine (FT4) in the serum of pregnant women close to or mildly above the upper limit of the reference value.
5. How to deal with hyperthyroidism during breastfeeding?
Anti-thyroid medications are safe to take in moderation during breastfeeding to treat hyperthyroidism. Generally methimazole (MMI) at a dose of 20-30mg per day and propylthiouracil (PTU) at 300mg per day are safe. However, since PTU may cause liver function damage, MMI may be preferred.
6. What about Hashimoto’s thyroiditis with normal thyroid function and only elevated autoimmune antibodies TPOAb and TGAb?
The prevalence of Hashimoto’s thyroid is up to 5% or more in the population. Most patients have only a low level of elevated autoantibodies against the thyroid tissue-specific proteins TG and TPO, but no significant symptoms of hypothyroidism. Since current studies have found that a diet high in iodine, such as salt iodization, significantly increases the likelihood of clinical thyroid function in this group of patients and accelerates the rate of hypothyroidism. Therefore, for this group of patients who only have elevated autoimmune antibodies TPOAb and TGAb without hypothyroidism, no medication is needed, but patients in non-iodine-deficient areas need to avoid foods with high iodine content and try to consume non-iodized salt to delay the onset of hypothyroidism.
7.What are the risks of hypothyroidism during pregnancy on pregnancy outcome and fetal development?
The prevalence of clinical hypothyroidism in pregnant women in the United States is 0.3%-0.5%; the prevalence reported in China is 1%. Most domestic and international studies have found that the incidence of preterm birth, miscarriage, low birth weight, and fetal death is significantly increased in pregnant women with hypothyroidism during pregnancy, and that hypothyroidism during pregnancy has adverse effects on fetal neurodevelopment. The most common cause of clinical hypothyroidism is Hashimoto’s thyroiditis, also called autoimmune thyroiditis, which accounts for about 80% of cases. Hypothyroidism in women during pregnancy must be treated promptly.
8.Under what conditions can a woman with clinical hypothyroidism become pregnant?
Before a hypothyroid woman plans to become pregnant, she needs to restore the concentration of thyroid hormone to normal by giving thyroid hormone (L-T4) replacement therapy. The specific treatment goal is to control the serum thyroid stimulating hormone (TSH) concentration to 0.1-2.5 mIU/L, and more ideally to achieve a TSH between 0.1-1.50.1-2.5 mIU/L.
9. What should I do if I have a thyroid nodule?
Thyroid nodules are very common. The prevalence of thyroid nodules that can be palpated by hand is about 3-7% in the general population, and up to 20% or more if high-resolution ultrasound is applied. The vast majority of thyroid nodules are benign and most do not require treatment, only regular follow-up. Therefore, if you have a thyroid nodule, don’t be nervous, but first go to the hospital for an ultrasound examination. Generally, nodules larger than 1 cm require a fine needle aspiration biopsy, while thyroid nodules smaller than 1 cm also require a fine needle aspiration biopsy under ultrasound guidance if malignancy is suspected. If fine needle aspiration does not clarify benign or malignant words, examination of the punctured cells for genetic mutations and molecular diagnosis are useful methods. Only patients with thyroid cancer or suspected thyroid cancer diagnosed by fine needle aspiration can be treated surgically.
10.How should I manage thyroid nodules during pregnancy?
Since pregnancy does not affect the development and prognosis of thyroid cancer and fine needle aspiration cytology biopsy (FNA) of the thyroid gland has no adverse effects on the mother and fetus; therefore, thyroid nodules found during pregnancy should undergo FNA if the ultrasound suspects the possibility of malignancy. Once the diagnosis of thyroid cancer is confirmed by fine needle aspiration, it is recommended that ultrasonography can be applied to detect the tumor if it is found early in pregnancy, and if the tumor grows rapidly before 24 weeks, surgery should be performed in mid-pregnancy. If the tumor remains stable until mid-pregnancy, or if the tumor is detected later in the pregnancy, surgery should be performed after delivery. If the fine needle aspiration biopsy is a benign nodule, it should generally not be treated and only ultrasound monitoring should be performed. Once the nodule is found to be growing rapidly or the ultrasound shows suspicious malignant lesion, surgery may be considered.