Basedow’s disease

Therapeutic strategies

There are three main therapeutic strategies: antithyroid medication, isotope (radioiodine) therapy, and surgery. In many cases, treatment starts with antithyroid medication, and then other treatments are considered in relation to the patient’s age, condition, social situation, and other factors.

Treatment with medication

In this method, patients regularly take drugs that suppress the production of thyroid hormones. Two types of medication, mercazole and Thiuragyl (propacil), are used. Patients are prescribed a drug regimen based on their condition, and thyroid hormone levels generally return to normal in approximately 1-3 months. The symptoms will disappear, allowing the patient to lead a normal life.
During treatment with medication, it is vital to regularly measure thyroid hormone levels. Patients must also continuously take prescribed drugs, with the dosage determined in relation to their condition. Prescription drug treatment lasts a minimum of two years and patients may need to continue taking medications longer. If normal thyroid function is maintained for at least half a year with the administration of the minimum dosage, concluding drug-based treatment will be considered. However, once a drug regimen is discontinued, it is important to regularly observe a patient’s condition. Thyroid hormone levels may increase again, indicating a recurrence of Basedow’s disease.
During the course of drug treatment, adverse reactions are possible. They occur most frequently 2-3 months following the start of the treatment. Patients need to be examined at the hospital every two weeks during this period.

【Adverse reactions to antithyroid drugs】

(1) Itching and rash

These reactions often occur 2-3 weeks after the start of treatment. If symptoms are mild, prescription of antiallergic drugs may allow continuation of thyroid treatment with medications. However, if adverse reactions occur even after co-administration of antiallergic drugs or if they are severe, antithyroid medication will need to be discontinued and other treatment options considered.

(2) Liver dysfunction

This adverse effect typically occurs between 2-12 weeks after the start of antithryoid drug treatment. Liver dysfunction is divided into two types. The first occurs when blood tests reveal abnormalities in levels of enzymes that reflect the liver’s condition, such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST). In this type, abnormalities are detected only in blood tests. The second type is when abnormal enzyme levels are accompanied with symptoms of jaundice. If AST or ALT levels are considerably high or if jaundice occurs, the antithyroid drug treatment will need to be discontinued. If mild liver dysfunction occurs temporarily, the drug regimen may be continued, but regular examinations are required to monitor liver function for a period of time after the treatment begins.

(3) Agranulocytosis

Granulocytes are a type of white blood cell found in the blood. Agranulocytosis occurs when the number of granuloctyes is reduced. Since granulocytes protect the body against invading viruses and bacteria, fewer granulocytes lead to high fever and a severe sore throat. Agranulocytosis tends to occur 2-12 weeks after treatment starts, but may occur later in the treatment process.
This adverse reaction is rare, occurring in 1-3 patients per 1,000. However, it can be serious and result in death. Patients should not assume that they have a cold and leave it untreated. If a high fever occurs during the treatment, patients will need to stop taking antithyroid medication and swiftly undergo a blood test to measure the granulocyte count.

(4) Other rare adverse reactions

Arthralgia (joint pain): Pain mainly occurs in the arm and leg joints, but the location may shift.
Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis: This condition is primarily caused by the medication Thiuragyl/propacil. For some patients, only joint pain occurs. Others may suffer from vascular inflammation of the kidney or lung, which can cause renal or pulmonary disorders. This condition may occur a few years after patients begin taking medication. It is necessary to exercise caution throughout the period of treatment.

Radioactive iodine isotope therapy

Iodine in food accumulates in the thyroid gland and is used as a raw material to produce thyroid hormones. Radioactive iodine also accumulates in the thyroid gland, and the radiation it emits degrades thyroid cells. As a result, the production of thyroid hormones is reduced.
After patients begin taking radioactive iodine capsule orally, the thyroid shrinks in size in approximately 2-6 months with thyroid hormone secretion gradually decreasing. However, there are individual differences in therapeutic effects. Whereas the therapy normalizes thyroid function and makes further treatment unnecessary in some patients, it causes hypothyroidism in others. In the latter, a continuing drug regimen to provide the body with thyroid hormones is necessary.
Before and after the therapy, the intake of iodine must be restricted. Also, antithyroid and iodine medications need to cease. Since thyroid hormone levels may fluctuate greatly for 4-6 months after the therapy, patients need to visit the hospital monthly to adjust their medications. Because this type of therapy uses radiation, we do not provide it to patients younger than 18 or to women who are pregnant or breastfeeding.

【Frequently asked questions about isotope therapy】

(1) Q: Is there a risk of cancer because this therapy uses radiation?
A: Statistical studies have demonstrated that there is no risk of cancer from isotope therapy. Furthermore, there is no evidence that this therapy has any effects on the offspring of patients who had previously received isotope therapy.

(2) Q: Will isotope therapy hurt my eyes?
A: It has been reported that approximately 2% of patients received eye care after isotope therapy because their eye symptoms worsened. Given this reality, it is necessary to perform an ophthalmologic examination (medical checkup and MRI) before isotope therapy in order to assess whether the patient is a suitable candidate.

Surgery

In this method, thyroid tissue that secretes excess levels of hormones is surgically removed. Partial resection is a previously used technique that involves the partial removal of the thyroid gland, leaving a small portion of tissue intact. However, because the recurrence rate of hyperthyroidism was high after partial removal, our hospital performs total resection in which the entire thyroid gland is removed.
Antithyroid drugs, which reduce thyroid hormone levels, can be discontinued the day after surgery. However, lifelong thyroid hormone replacement medication is required after total resection. Thyroid replacement hormones have little risk of adverse reactions. After the dosage becomes stable, medications can be prescribed for longer periods and the frequency of hospital visits is reduced.

【Advantages of total resection】

(1) Recurrence rate is low.
(2) Levels of anti-TSH receptor antibodies (TRAb) are usually normalized earlier than in subtotal resection.

Selecting a therapeutic strategy

Each of the therapeutic strategies has advantages and disadvantages. It is necessary to consider the patient’s condition, age, social situation, and other individual factors when selecting an appropriate therapeutic strategy. In addition, since a patient’s condition may change during the course of treatment, the therapeutic strategy may be altered accordingly.