Authoritative interpretation of the 2022 new guide to hyperthyroidism

Hyperthyroidism is a common disease of the endocrine system, with the characteristics
of a large number of patients, serious harm and complex diagnosis and treatment.
In order to strengthen the standardized management of clinical diagnosis and treatment of hyperthyroidism in China, the Endocrinology Branch of the Chinese Medical Association and a number of academic (associations) issued the "Guidelines for the Diagnosis and Treatment of Hyperthyroidism and Other Causes of Thyrotoxicosis in China" (hereinafter referred to as the "Guidelines")
this year.

Recently, the first stop of the "Armor City Tour" 2022 China Thyroid Guide Core Cities Tour was successfully held
in Shenyang.

Professor Teng Weiping

President of the Conference/Director of the Institute of Endocrinology, China Medical University/Vice President of the Asian Regional Thyroid Society

Professor Teng Weiping said in his speech: "The new version of the Guidelines has been repeatedly revised for more than a year by domestic authoritative societies, with reference to the latest relevant literature, and condenses the research efforts of the thyroid community and colleagues in various disciplines
.
It is hoped that through this tour and interpretation, doctors will better follow the Guidelines and jointly promote the standardized diagnosis and treatment
of hyperthyroidism.
”

Professor Zhongyan Shan

One of the editors-in-chief of the new edition of the Guideline/Head of the Thyroidology Group of the Endocrine Society of the Chinese Medical Association/Director of the Department of Endocrinology, The First Affiliated Hospital of China Medical University

Professor Shan Zhongyan pointed out: "The diagnosis and treatment of hyperthyroidism is more complicated, and the diagnosis and treatment methods are different for different groups, so it is urgent to standardize the management
of hyperthyroidism clinically.
Previously, China's first hyperthyroidism guideline was released in 2007, and after 15 years, the field of hyperthyroidism diagnosis and treatment has undergone rapid development, providing more evidence-based medical evidence
for the update of the guidelines.
The new edition of the Guidelines cites a large number of literature and studies, with a total of 107 recommended items, providing authoritative guidance for clinical practice
.
”

See the subtleties

Anatomy of thyrotoxicosis and Graves disease

Patients with thyrotoxicosis have similar clinical manifestations of different etiologies, but treatment options and prognosis are different, so accurate diagnosis and differential diagnosis of thyrotoxicosis etiology is critical
.
The Guidelines provide a detailed and clear review of its etiology and clinical manifestations, and recommend free triiodothyronine (FT3) and free thyroxine (FT4) as the main indicators
for the diagnosis of thyrotoxicosis.

Professor Shan Zhongyan pointed out: "Studies have shown that under the premise of normal hypothalamic-pituitary-thyroid axis, changes in thyroid-stimulating hormone (TSH) are sensitive to changes in FT4, so TSH is the most sensitive indicator
for diagnosing primary thyroid disease.
The Guidelines recommend that third-generation immunoassays should be used as the most sensitive indicator of initial screening in the diagnosis of thyrotoxicosis
.
In addition, the Guidelines recommend that thyrotropin receptor antibodies (TRAb) measured by third-generation immunoassays be used to identify
the cause of thyrotoxicosis.
”

In the diagnosis of hyperthyroidism in Graves disease (GD), the Guidelines follow the criteria of the 2007 version of the Guidelines and recommend that patients with the characteristic clinical manifestations of GD can be diagnosed with GD; When the clinical manifestations of patients cannot determine the cause, TRAb detected by the third-generation immunoassay is recommended as the basis for the diagnosis of GD.
When TRAb is negative or low titer positive, thyroid ECT imaging or ultrasound can be used to measure peak blood flow velocity in the arteries of the internal thyroid to aid in the diagnosis of GD.

The Guidelines provide clear recommendations and guidance
for the drug, 131I treatment and surgical treatment of GD.
Speaking about the indications for discontinuation of GD drug treatment, Professor Shan Zhongyan pointed out: "Three conditions need to be met for the discontinuation of antithyroid drugs (ATDs): first, the course of treatment is sufficient, the previous guidelines recommended 12-18 months of treatment, and the new version of the Guidelines extends the treatment time, recommending 18-24 months; Second, TRAb is negative, the Guidelines point out that TRAb is a good indicator for predicting prognosis, it is recommended to test TRAb before stopping the drug, if negative, it indicates that the possibility of remission is great, and those with high titer TRAb are recommended to extend the course of treatment appropriately; Third, small doses of ATDs to maintain TSH normal, it should be noted that small doses of nail merimazole are usually 2.
5 mg or 2.
5 mg orally every other day, if the drug is reduced or repeatedly aggravated after stopping the drug, it is necessary to extend the course of treatment to improve the remission rate, and some studies have shown that it can be up to 10 years
.
”

In addition, Professor Shan Zhongyan emphasized: "The new version of the Guidelines has a fundamental change
in concept about the purpose of radioactivity 131I treatment.
Previous guidelines considered hypothyroidism to be a major complication of 131I treatment of hyperthyroidism, but now we believe that the purpose of 131I treatment is to eliminate hyperthyroidism, so the new version of the Guidelines lists hypothyroidism as one of the criteria for the efficacy of
131I treatment.
”

constantly improve something

Interpretation of rare types of hyperthyroidism and hyperthyroidism in special patients

The Guidelines provide clear guidance for
the diagnosis and treatment of rare types of hyperthyroidism, including toxic multinodular goiter (TMNG) and toxic thyroid adenoma (TA hyperthyroidism), subclinical thyrotoxicosis, Graves ophthalmopathy (GO), thyrotoxicosis caused by other causes, and drug-induced thyrotoxicosis.

The Guidelines make it clear that subclinical thyrotoxicosis refers to various causes that cause TSH levels to be lower than the lower limit of the reference range, while T4 and T3 are within the reference range, and a flowchart
of the etiology diagnosis of subclinical thyrotoxicosis is given.

Flow chart for diagnosing the etiology of subclinical thyrotoxicosis

Prof.
Jing Li

Department of Endocrinology, The First Affiliated Hospital of China Medical University

Professor Li Jing pointed out: "It should be noted that non-thyroid TSH reduction must be excluded in the diagnosis process, heterophilic TSH antibody interference, high-dose use of glucocorticoids, mental anxiety and other factors may have non-thyroid TSH level reduction, therefore, the diagnosis of subclinical thyrotoxicosis must be differentiated
.
" "The Guidelines recommend that subclinical hyperthyroidism with a persistent TSH < 0.
1 mU/L, or patients aged ≥ 65 years, or with comorbidities (heart disease, osteoporosis, etc.
) and symptoms of hyperthyroidism, should be treated
.
"

For all GO, the Guidelines update the diagnostic criteria to recommend a GO diagnosis
after exclusion of other ophthalmic conditions through relevant clinical symptoms, signs, and ancillary tests.
The Guidelines make it clear that all patients with GO should recover and maintain normal thyroid function and correct risk factors as soon as possible, and that all patients should quit smoking
.

"For thyrotoxicosis caused by other causes, attention should be paid to the differentiation of TSH-secreting pituitary adenoma and thyroid hormone resistance, because both are FT3, FT4 is elevated, TSH is not inhibited, differential diagnosis is difficult, the guideline clarifies the indicators
of differential diagnosis.
" Professor Li Jing pointed out, "In addition, destructive thyroiditis is more common in clinical work, and the use of ATDs
is not recommended.
β-blockers can be used to control symptoms and monitor nail function
closely.
Patients with ovarian goiter often have a history of amenorrhea, so hCG testing is also very important to help distinguish hCG-related thyrotoxicosis and functional thyroid cancer metastasis
.
”

The Guidelines also describe
the treatment of hyperthyroidism in several special categories of patients, such as children and adolescents, pregnant and elderly patients.
First-line treatment of patients with GD in children and adolescents with new diagnosis should be ATDs; Women of childbearing age with GD should become pregnant after normal and stable thyroid function to reduce adverse pregnancy outcomes; For older patients, a comprehensive assessment of geriatric patients (CGA) is recommended to comprehensively assess elderly patients with hyperthyroidism to guide treatment and estimate disease risk and prognosis
.

Eliminate the false and save the truth

Addressing the challenges of thyroid function testing

Efficient and accurate detection of thyroid function indicators is an important basis for
the standardized diagnosis and treatment of hyperthyroidism.

Prof.
Xinqi Cheng

Department of Clinical Laboratory, Peking Union Medical College Hospital

Professor Cheng Xinqi emphasized: "On the one hand, the challenges in the interpretation of nail function test results are reflected in the complexity of the nail function mode, about 1%-10% of the nail function test results require special tracking and interpretation, and the test results of different platforms are inconsistent, requiring more clinical and technical support; On the other hand, the patient's physiological factors (age, sex, physiological status), pathological factors (disease/medication) and interfering factors in the test will all affect the results of thyroid function and need special attention
.
”

Professor Cheng Xinqi pointed out through a series of examples that circadian rhythm, gender, sleep time changes, eating and blood collection time, season, pregnancy and other factors will have different degrees of influence on the nail function test results, he pointed out: "Taking pregnant women as an example, their TSH level is 0.
4mIU/L lower than that of non-pregnant women, and FT4 levels have also changed to a certain extent, so the reference range
of TSH and FT4 during pregnancy should be used.
" In addition, children and the elderly are also suitable to use specific reference intervals
due to age factors.
”

Pregnancy also has an effect on TRAb levels, and patients with GD during pregnancy tend to decline due to autoimmune suppression during pregnancy, but TRAb levels at high levels (above 3-5 times the upper limit of normal reference values) may not fall to normal
.

For the influencing factors in the assay, including giant TSH, heterophile antibodies, thyroid autoantibodies, etc.
, Professor Cheng Xinqi analyzed them one by one, and summarized some ways to identify assay interference, such as replacing the detection system for retesting, performing dilution after measurement, and using blocking proteins/chimeric antibodies, etc.
, which can help determine whether there is interference and reduce the bias
of test results.
In addition, improvements in detection methodology have also helped to improve the accuracy
of testing.

Professor Cheng Xinqi concluded: "We should not only pay attention to the test results themselves, but also pay attention to the information beyond the test sheet; Only comprehensive judgment and analysis of the patient's clinical manifestations, imaging results and laboratory test results can remove the interference and provide more reliable support
for precision diagnosis and treatment.
”

In the field of thyroid disease, Roche Diagnostics has Elecsys that comprehensively covers thyroid function, autoantibodies, and tumor markers.
The overall solution of thyroid serum detection and the key management index TRAb of Graves disease unique to Roche Diagnostics; Combined with the thyroid serum detection auxiliary software (TSTF) recommended by Roche Diagnostics, through digital means, it provides laboratory doctors with in-depth interpretation and reference of thyroid function test results, strengthens efficient communication between laboratories and clinics, creates an ecological closed loop of accurate diagnosis and treatment of thyroid diseases, and provides strong support
for promoting the standardized diagnosis and treatment of hyperthyroidism.