Most of the endocrine disorders are related to hormonal imbalance. In addition to treating the cause, the most important thing is to restore the normal level of hormones. This adjustment process needs to be very delicate, one part too much, one part too little, just the right amount… but it is not easy to achieve this, and in clinical practice there are often “overkill” and “too little”. This is often the case in clinical practice. Here, we will talk about the problem of over-treatment of hyperthyroidism. What are the dangers of overtreatment of hyperthyroidism? The latter is no less harmful than hyperthyroidism, which can cause hypometabolism (such as weakness, chill, slow heartbeat, etc.) and decreased sympathetic excitability (such as oligophrenia, drowsiness, depression, etc.), and has a more serious impact on pregnant women, leading to miscarriage, premature birth and fetal neurointellectual development. 2. Overtreatment of hyperthyroidism can lead to feedback elevation of TSH, which can cause or aggravate goiter and proptosis. 3. Overtreatment of hyperthyroidism also increases the toxic side effects of antithyroid drugs (ATD) on the body, leading to leukopenia, liver damage, allergic dermatitis, etc. What are the common cases of overtreatment of hyperthyroidism? 1. Improper mastering of the indications of anti-thyroid drugs (ATD) Hyperthyroidism (referred to as “hyperthyroidism”) refers to a group of clinical syndromes caused by elevated levels of thyroxine in the blood due to various reasons. In addition to the familiar Graves’ disease (diffuse goiter with hyperthyroidism), there are many other types of hyperthyroidism, including “transient hyperthyroidism” caused by subacute thyroiditis or chronic lymphocytic thyroiditis (Hashimoto’s disease). Although the latter is also hyperthyroidism in a broad sense, it is not due to hyperthyroid hormone synthesis and secretion (e.g., Graves’ disease), but rather to increased thyroxine release due to destruction of thyroid cells. Anti-thyroid drug (ATD) therapy is usually not required. Even for the few patients with severe symptoms, only a small dose of ATD is needed for a short period of time, otherwise the patient is very vulnerable to hypothyroidism. There is also “hCG-related hyperthyroidism”. It occurs mainly in early pregnancy and is associated with elevated levels of human chorionic gonadotropin (hCG). Since hCG is chemically similar to TSH, hCG has the same excitatory effect on TSH receptors on the surface of thyroid cells, resulting in a mild increase in FT4 or FT3 and a decrease in TSH levels. “The hCG-related hyperthyroidism is a transient physiological change in early pregnancy, with mild symptoms of hyperthyroidism, and usually does not require anti-thyroid medication. As the pregnancy progresses, the hCG level gradually decreases and the thyroid hormone level can return to normal on its own. Finally, it should be noted that unlike subclinical hypothyroidism in pregnancy, subclinical hyperthyroidism in pregnancy does not require ATD intervention because there is no evidence to confirm the association between subclinical hyperthyroidism and poor pregnancy outcome and fetal outcome. “The reason is that there is no evidence that subclinical hyperthyroidism is associated with adverse pregnancy outcomes and fetal brain development disorders. 2. Inappropriate dose adjustment of antithyroid drugs (ATD) The treatment of hyperthyroidism is chronologically divided into three phases: “control phase”, “dose reduction phase” and “maintenance phase”. The purpose of the control phase is to control the synthesis and secretion of thyroid hormones and to rapidly relieve the symptoms. However, care should be taken not to overdose the medication and not to use it for too long (usually 4-6 weeks). Otherwise, it may lead to enlargement of the thyroid gland or aggravation of the original proptosis. Secondly, medication should be individualized and the dose should not be too high to prevent overkill; thirdly, during medication, thyroid function (FT3, FT4, TSH) should be monitored frequently and the dosage should be adjusted according to the test results. According to the test results, the dosage should be adjusted.