Will there be any side effects of iodine absorption rate in treating hyperthyroidism

Iodine absorption rate is more suitable for the treatment of hyperthyroidism in normal times. It is important to understand the correct dosage and usage. Because a small number of patients with thyroid function must clearly judge whether their body meets the therapeutic effect of iodine absorption rate when using iodine absorption rate, so as to avoid excessive use. Cause some unnecessary complications. Pay attention to the analysis of the condition, timely diagnosis, and preventive work. Drugs cannot be used indiscriminately, and be sure to consult a doctor before use.

Clinical significance

Hyperthyroidism: In hyperthyroidism, the rate and intensity of iodine absorption by the thyroid gland increase, so the peak of iodine absorption occurs earlier. For this reason, the oral method often uses the 2, 3, or 4 hour measurement method. If the 131 iodine absorption rate is greater than 25% in 3 hours, greater than 30% in 4 hours, and greater than 47% in 24 hours, it has diagnostic significance. The results of the oral test are affected by thiourea drugs, so this method should not be used while taking medication.

Hypothyroidism: Primary and secondary hypothyroidism, the thyroid 131 iodine absorption rate is significantly reduced. Normally, the 24-hour 131 iodine absorption rate is less than 15%. In severe cases, it is close to 0.

Sporadic simple goiter: This disease has no clear relationship with iodine deficiency. A variety of causes increase the physiological need for thyroid hormone and thyroid hormone synthesis disorders, all of which can cause patients to have relative or absolute thyroid hormone deficiency, leading to increased TSH secretion and increased iodine-131 absorption by the thyroid gland. Unlike hyperthyroidism, the absorption peak of this disease does not shift forward.

Endemic goiter: Endemic goiter is mainly caused by iodine deficiency. When iodine is deficient, thyroid hormone synthesis is insufficient and TSH secretion increases. In addition, when iodine is deficient, the main part of the thyroid hormone that increases in the blood is T3, which contains less iodine than T4 but has stronger biological activity. Therefore, early patients do not show symptoms of hypothyroidism. In the late stage, due to long-term excessive TSH stimulation, thyroid epithelial cells tend to fail, which can lead to hypothyroidism. Due to iodine deficiency and increased TSH, the absorption rate of iodine-131 is usually significantly increased. Unlike hyperthyroidism, the peak of iodine absorption does not shift forward.

Iodine rate test

Normal value

1. Diagnostic indicators of hyperthyroidism: (1) The isotope iodine absorption rate is higher than the upper limit of normal value; (2) The ratio of the 2.3-hour isotope iodine absorption rate to the 24-hour isotope iodine absorption rate is greater than 0.8 hour or the ratio of 4 hours to 24 hours is greater than 0.85; (3) The peak of the isotope iodine absorption rate is shifted forward, that is, the highest isotope iodine absorption rate appears before 24 hours. Hyperthyroidism can be diagnosed if two of (1) and (2) or (3) are met. Increased isotope iodine absorption rate sometimes needs to be differentiated from increased isotope iodine absorption rate in endemic goiter and a few sporadic goiters.

2. Diagnostic indicators of hypothyroidism: The absorption rate of each isotope iodine is lower than the lower limit of normal value. Sometimes it is necessary to differentiate between thyroiditis, ectopic thyroid, iodine-containing drugs, food effects, and other factors that reduce the absorption rate of isotopic iodine.

Clinical significance

In general, the first choice for evaluating thyroid function is to measure serum TSH and thyroid hormone concentrations. But in some cases, thyroid isotope iodine absorption test is an indispensable examination for the diagnosis and treatment of thyroid diseases.

[ Points to note ]

When analyzing the results, attention should be paid to the influence of other pathophysiological conditions.