2016 Guidelines for Diagnosis and Management of Hyperthyroidism Issued

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In late 2016, the American Thyroid Association issued their new “Guidelines for Diagnosis and Management of Hyperthyroidism and Other Causes of Thyrotoxicosis.” The new guidelines were published in the journal Thyroid, and presented evidence-based clinical guidelines to manage hyperthyroidism—also known as thyrotoxicosis. These guidelines are an update to the 2011 guidelines published by the ATA. In this article, we review some important highlights of key information presented in the guidelines.

Basics

The guidelines use the term thyrotoxicosis, which refers to "a clinical state that results from inappropriately high thyroid hormone action in tissues generally due to inappropriately high tissue thyroid hormone levels. The term “hyperthyroidism,” as used in these guidelines, is a form of thyrotoxicosis due to inappropriately high synthesis and secretion of thyroid hormone(s) by the thyroid."

According to the guidelines, the prevalence of hyperthyroidism in the United States is approximately 1.2 percent (0.5 percent with overt hyperthyroidism, and 0.7 percent with subclinical clinical hyperthyroidism.)

The main causes and risk factors for thyrotoxicosis include:

  • excessive stimulation of the thyroid by trophic factors (helper molecules that allow a neuron to develop and maintain connections)
  • activation of the synthesis of thyroid hormones that results in excessive release of those hormones, including iodine-induced hyperthyroidism
  • excessive release of thyroid hormones due to autoimmunity, infection, chemical exposures, or physical injury or impact to the thyroid gland
  • exposure to other sources of thyroid hormone, which can be internal (such as from certain tumors), or external (such as supplements that contain thyroid hormone, or overdosage of prescription thyroid hormone replacement drugs

    The most common causes of hyperthyroidism include:

    • Graves' disease: an autoimmune condition that triggers overactivity in the thyroid gland. Graves' disease is the most common cause of hyperthyroidism in the United States.
    • Toxic multinodular goiter: an enlarged thyroid, with multiple nodules
    • Toxic adenoma: a benign tumor of the thyroid gland
    • Thyroiditis: inflammatory conditions of the thyroid gland. Some cases of thyroiditis are due to infection or autoimmunity, and some can be triggered by drugs, including lithium, interferon-α, anti-cancer drugs known as tyrosine kinase inhibitors, and the heart drug amiodarone.

    Hyperthyroidism can be categorized as overt or subclinical.

    • Overt hyperthyroidism: below-normal or undetectable thyroid stimulating hormone (TSH) level, with elevated free T3/T3 and/or free T4/T4.
    • Subclinical hyperthyroidism: Low or undetectable TSH level, with free T3/T3 and/or free T4/T4 in the reference range.

    Identifying the Cause

    The guidelines recommend that the underlying cause of your thyrotoxicosis should be determined. if a clear cause can't be identified, then the guidelines recommend that your doctor measures thyrotropin receptor antibodies (TRAb), performs a radioactive iodine uptake (RAIU) scan, and/or orders an ultrasound evaluation of thyroid.

    If toxic adenoma or toxic multinodular goiter is suspected, the guidelines also recommend you have a radioactive iodine-123 or technetium scan.

    Beta-Blocker Treatment

    Beta-blocking drugs—which help lower your heart rate and blood pressure—are recommended for all patients who have thyrotoxicosis symptoms such as elevated heart rate and/or blood pressure. The guidelines recommend them particularly if you are a senior, if you have a resting heart rate about 90 beats per minute, or if you have pre-existing heart disease.

    Graves' Hyperthyroidism Treatments

    If you have overt Graves' disease, the guidelines outline your three treatment options: radioactive iodine (RAI) therapy, antithyroid drugs, or thyroidectomy—surgery to remove your thyroid gland.

    According to the guidelines, RAI has been the preferred treatment in the US, but there is a trend toward increased use of antithyroid drugs over RAI.

    Here are some key considerations for each treatment approach:

    • RAI: RAI is not done during pregnancy or while breastfeeding, or if you have been diagnosed with or are suspected to have thyroid cancer. Also, if you want to get pregnant, you will need to wait from 6 months to a year after RAI, and until thyroid levels are normalized. RAI is also not done if you are unable to follow radiation safety guidelines after treatment, to protect others from radiation exposure. The guidelines also recommend that you have a pregnancy test within 48 hours prior to RAI treatment if you are a women with childbearing potential.
    • Antithyroid Drugs: The guidelines suggest antithyroid drugs if you have mild disease, lack of autoimmune disease, are pregnant, are unable to follow radiation safety regulations after RAI treatment, have thyroid eye disease, or need rapid control of your condition. If you have previously had, or are having a reaction to antithyroid drugs, the guidelines recommend that they be avoided.
    • Surgery: Surgery is recommended if you have a large goiter or the thyroid enlargement is impairing your breathing or swallowing. Surgery is also recommended if cancer is suspected or diagnosed, if you have moderate or severe thyroid eye disease, or if you have very high antibodies. Surgery is not recommended if you have significant heart disease, or other factors that make surgery or anesthesia a risk. Surgery during pregnancy is not recommended unless absolutely necessary, and even then, only in the second trimester when there is the lowest risk of fetal loss or premature labor. The guidelines recommend that you choose a thyroid surgeon who does a high volume of surgeries annually, as this significantly reduces the risk of thyroid surgery complications.

    Factors Affecting Your Choice of Treatment

    According to the guidelines, there are also personal factors that affect your choice of treatment:

    • RAI: If you choose RAI, you likely want more control over your hyperthyroidism, would like to avoid surgery, and would like to avoid potential side effects of antithyroid drugs. You are also likely to be less concerned with the need for rapid resolution of your hyperthyroidism, with the need for lifelong thyroid hormone replacement treatment, and the potential worsening of thyroid eye disease.
    • Antithyroid Drugs: If you choose antithyroid drug treatment, you likely are placing more importance on the potential for remission and want to potentially avoid lifelong thyroid hormone replacement treatment and surgery, as well as avoiding exposure to radioactivity. The possibility of recurrence is also likely to be less important to you.
    • Surgery: If you choose surgery, you likely feel that fast and definitive control of your hyperthyroidism is most important, along with avoiding radioactive exposure, and antithyroid drug side effects. The need for lifelong thyroid hormone replacement treatment is also likely less important to you. 

    Radiation Safety After RAI

    The guidelines recommend that your doctor provide you with written guidelines regarding precautions you need to take after RAI treatment.

    Your doctor will provide specifics, but generally, according to the American Thyroid Association, you will need to observe the following post-RAI radiation safety precautions. The length of time recommended is dependent on your RAI dose:

    Sleep in a separate bed (~6 feet of separation) from another adult: 1-11 days

    Delay return to work: 1-5 days

    Maximize distance from children and pregnant women (6 feet): 1-5 days

    Limit time in public places: 1-3 days

    Do not travel by airplane or public transportation: 1-3 days

    Do not travel on a prolonged automobile trip with others: 2-3 days

    Maintain prudent distances from others (~6 feet): 2-3 days

    Drink plenty of fluids: 2-3 days

    Do not prepare food for others: 2-3 days

    Do not share utensils with others: 2-3 days

    Sit to urinate and flush the toilet 2-3 times after use: 2-3 days

    Sleep in a separate bed (~6 feet of separation) from pregnant partner, child or infant: 6-23 days

    Your physician should follow up within 4 to 8 weeks after RAI, to measure your free T4, total T3, and TSH. This monitoring should continue every 4 to 6 weeks, to detect the hypothyroidism that occurs in 40 percent of patients by week 8, and 80 percent of patients by week 16. Once hypothyroidism is detected, thyroid hormone replacement should be promptly started.

    Antithyroid Drug Treatment

    If you are being treated with antithyroid drugs, the drug methimazole (Tapazole)—also abbreviated as MMI—should be used. The only exception is if you are in the first trimester of pregnancy, are being treated for thyroid storm, or you have reacted to MMI and do not want RAI or surgery.

    According to the guidelines, if you have any of the following side effects, you need to contact your physician immediately:

    • an itchy rash
    • jaundice/yellowing of the skin
    • dark colored urine
    • pain in joints
    • pale or clay-colored stools
    • abdominal pain
    • nausea
    • fatigue
    • fever
    • sore throat

    Your free T4 and total T3 should be measured 2 to 6 weeks after you start antithyroid drug treatment. Once your levels are normalized, the dose of MMI can typically be reduced by up to half. After any change in dose, testing should be repeated within 4 to 6 weeks. Once you have stabilized, the guidelines recommend testing every 2 to 3 months, and if you have been taking MMI for more than 18 months, every 6 months.

    The guidelines also recommend that your physician get a differential WBC blood count if you are sick with a fever and/or upon the onset of a sore throat.

    If you become hyperthyroid after MMI treatment, your doctor may want you to consider RAI or surgery, but continuing on MMI may also be considered if you are not in a remission.

    Thyroid Surgery

    If surgery is chosen as treatment for Graves' disease, ideally you should have normal thyroid function prior to treatment. Pre-operative treatments should include potassium iodide, and a beta-blocker is also an option. Your calcium and vitamin D-25-hydroxy should also be measured prior to surgery, and supplemented if needed.

    If you need surgery immediately, before you can be restored to normal thyroid levels, the guidelines recommend beta blockers, potassium iodide, and steroid drugs before surgery.

    Again, the guidelines also recommend that you choose a “high-volume” thyroid surgeon who does many thyroid surgeries each year. This improves your outcome, and reduces risks of any complications.

    Some Considerations for Treatment in Children

    The guidelines recommend that antithyroid drug treatment with MMI (not PTU) for a year be the first-line treatment for most children, due to the high likelihood of remission in these children. Ultimately, however, the majority of children will require RAI or surgery.

    The guidelines state that RAI therapy should be avoided in children under the age of 5.

    Treating Subclinical Hyperthyroidism

    The guidelines recommend treating subclinical hyperthyroidism when certain factors are present:

    • your TSH level is consistently below 0.1 mU/L
    • if you are over 65
    • if you have risk factors for heart disease or osteoporosis
    • if you are a postmenopausal woman not taking estrogen or drugs to prevent or treat osteoporosis
    • if you have symptoms of hyperthyroidism

    Some Considerations for Treatment During Pregnancy

    The guidelines recommend that during pregnancy, you should be treated with the lowest possible dose of antithyroid drugs (PTU during the first trimester, and MMI during the second and third trimesters) that can keep your thyroid levels within or just slightly above the reference range in pregnancy. Your thyroid function should be evaluated monthly, and medication doses adjusted as required.

    What The Guidelines Mean for You

    If you have been diagnosed with Graves’ disease, hyperthyroidism, or thyrotoxicosis, it’s recommended that you familiarize yourself with the full guidelines. You can read and download a PDF version of the new guidelines here.

    Source:

    Ross Douglas S., Burch Henry B., Cooper David S., Greenlee M. Carol, Laurberg Peter, Maia Ana Luiza, Rivkees Scott A., Samuels Mary, Sosa Julie Ann, Stan Marius N., and Walter Martin A.. Thyroid. October 2016, 26(10): 1343-1421. doi:10.1089/thy.2016.0229. Online PDF

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