Use the “5 Bs” to treat acute hyperthyroidism

Antithyroid drugs, radioactive iodine, surgery are main treatments.

When treating acute hyperthyroidism in the inpatient setting, remember the “5 Bs,” advised Hossein Gharib, MD, MACP.

Dr. Gharib, who is a professor at the Mayo Clinic College of Medicine in Rochester, Minn., and president of the American Thyroid Association, offered advice on treatment of acute hyperthyroidism as part of a session titled “Clinical Triad: Endocrinology for the Hospitalist,” held at Internal Medicine 2014 in Orlando, Fla., in April.

The 5 Bs are:

  1. 1. Block hormone synthesis with antithyroid drugs;
  2. 2. Block hormone release by administering iodine for patients with excess thyroid and hyperthyroidism, “commonly a patient with hyperthyroidism and Graves' disease,” Dr. Gharib noted;
  3. 3. Block T4 to T3 conversion with propylthiouracil (PTU);
  4. 4. Beta-blockade using propranolol or metoprolol; and
  5. 5. Block enterohepatic circulation with cholestyramine, “an agent that is seldom used nowadays,” he noted.

The main treatment categories for acute hyperthyroidism are antithyroid drugs, radioactive iodine, and surgery, Dr. Gharib said. Antithyroid drugs have the advantage of being nonablative but have recurrent side effects. Radioactive iodine and surgery both have the advantage of being definitive, but patients may be afraid of receiving radioactive treatment, and surgery may lead to complications, Dr. Gharib said.

Antithyroid drugs are easy to use and have a high probability of remission if glands are small, disease is mild, and antithyroid antibodies and thyroid autoantibodies are negative, Dr. Gharib said. They are the agents of choice in patients at high risk for surgery and in patients with moderate to severe Graves' ophthalmopathy, he noted. They are also a good alternative for patients and physicians who are not comfortable with ablative therapy.

Disadvantages of antithyroids, however, include the long-term commitment involved, the lower overall remission rates in U.S. practice, and potential side effects. In addition, Dr. Gharib said, “If there's a question of pregnancy, management during pregnancy becomes an issue.”

Methimazole, 10 to 40 mg/d, is currently the recommended antithyroid drug for hyperthyroid Graves' disease in adults, Dr. Gharib said. If it is chosen as the primary therapy, it should be continued for approximately 12 to 18 months, then tapered or stopped if the thyroid-stimulating hormone level is normal, he noted. PTU is no longer used for routine treatment of hyperthyroidism in adults due to fulminant hepatotoxicity; the only exceptions are for patients in the first trimester of pregnancy or those who have a thyroid storm, when the aim of therapy is to block thyroxine-to-T3 conversion, Dr. Gharib said.

White blood count and liver profile should be checked before treatment with antithyroid drugs is initiated, Dr. Gharib said, but routine monitoring of these lab values during treatment is no longer needed, unless there is a clinical indication. If the patient relapses during treatment with antithyroid drugs, consider radioactive iodine or thyroidectomy, Dr. Gharib advised.

Beta-blockade is a good addition to treatment of patients with hyperthyroidism and is especially useful in those with tachycardia, Dr. Gharib said. Propanolol, 40 to 80 mg orally every 6 hours, is recommended; it can also be given intravenously. Cardioselective agents such as atenolol and metoprolol, 50 to 100 mg orally every 8 hours, can be used in patients with airway disease. Beta-blockade can continue as long as it is needed, Dr. Gharib said. “Usually we use [it] in conjunction with radioiodine therapy or with antithyroid drugs.”

Therapy with radioiodine has the advantages of being effective, simple, safe, and economical, Dr. Gharib said. Women planning pregnancy in the near future can use radioiodine, “but then they would have to become euthyroid before considering pregnancy,” he noted. High-risk surgical patients can also be good candidates for this therapy, he said.

Disadvantages of radioiodine include when uptake is low and the fact that some patients may be anxious about radiation, he noted. It is also contraindicated in pregnant or breastfeeding patients, while moderate to severe Graves' ophthalmopathy is considered a relative contraindication. In addition, he said, “Most patients, 98%, develop post-therapy hypothyroidism requiring lifelong replacement thyroxine therapy.”

Surgery may be the optimal therapy if patients have a compressive or large goiter, if radioactive iodine is low, or if Graves' ophthalmopathy is present. “These are indications that would push you towards offering patients surgical treatment,” Dr. Gharib said. In addition, he noted, “a woman who wants to get pregnant soon would need to be euthyroid, and surgery offers that opportunity.”

Surgery is also preferred in patients with a suspicious nodule and in elderly patients who may need prompt relief of hyperthyroidism. However, any surgery carries risks, and patients should see a high-volume surgeon, who may not always be available, Dr. Gharib said. Post-treatment hypothyroidism is also an issue with surgery, he noted.

When treating Graves' disease, physicians should always discuss logistics, benefits, speed of recovery, drawbacks, potential side effects, and costs of a potential therapy with the patient, Dr. Gharib stressed.

“Then decide with the patient whether or not this or another modality can be used,” he said. “The final decision is based on your personal experience and preference, and what the patient tells you.”