Hyperthyroidism (Overactive Thyroid)

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Hyperthyroidism, also known as overactive thyroid, is a condition in which the thyroid gland produces too much thyroid hormone. Too little thyroid-stimulating hormone produced by the pituitary gland also can cause hyperthyroidism.

The main thyroid hormones, primarily thyroxine (T4) and triiodothyronine (T3), play a crucial role in regulating the body’s metabolism. An abnormally high thyroid hormone level can increase your heart rate and make you feel anxious and tired. Hyperthyroidism can be caused by various factors, and its symptoms can range from mild to severe.

Hyperthyroidism affects about 1 in 100 people and is more common in women and those over age 60. Hypothyroidism describes an underactive thyroid that produces too little thyroid hormone.

Thyroid hormones affect nearly every organ in your body, and excess thyroid hormone can cause heart issues and put you at increased risk for stroke.

Your treatment for hyperthyroidism will depend on your age, your symptoms, any other conditions you have, the cause of your hyperthyroidism and other factors, according to the American Thyroid Association.

Subclinical hyperthyroidism is a mild form of the condition. It occurs when the pituitary gland produces low levels of thyroid-stimulating hormone, but T3 and T4 levels are normal. Often, the condition has no symptoms. Subclinical hyperthyroidism often warrants monitoring, but no treatment.

Red and swollen eyes or bulging eyes can be signs of thyroid eye disease.

Thyroid eye disease primarily affects those with Graves disease, an autoimmune condition that causes hyperthyroidism. Inflammation and swelling of the muscles and tissues around the eyes leads to telltale eye symptoms.

Norton Now includes same-day care options so you can get the care you need, when you need it and where you need it. Norton Community Medical Associates primary care offices are located across Louisville, Southern Indiana and beyond. Save your spot in line at a Norton Immediate Care Center or visit a Norton Prompt Care clinic for treatment of minor injuries or illnesses.

Use Norton eCare video visits, or eVisits which require no video — just answer a few questions online from anywhere in Kentucky or Indiana for care without coming into the office. Your provider can order drive-thru lab testing for you at Norton Healthcare Express Services if it’s needed.

Norton Community Medical Associates – Endocrinology locations also offer easy access to specialized care from endocrinologists to help you treat thyroid disease and manage antithyroid medication.

Diagnosing Hyperthyroidism

Determining whether you have hyperthyroidism typically will start with a physical exam that can reveal an enlarged thyroid or thyroid nodules. Your medical provider also will look for symptoms such as a fast heartbeat, shaky hands or skin that is warm and moist.

Blood tests will measure your thyroid hormone level, thyroid antibodies and other signs of high thyroid hormone levels. Imaging tests such as thyroid ultrasound or nuclear medicine scans can help determine why your thyroid is overactive, according to the American Thyroid Association.


Overactive thyroid gland treatment is aimed at bringing your hormone levels down to normal. Treating the disease will prevent long-term health issues and relieve uncomfortable symptoms. There’s no one-size-fits-all treatment, since no single treatment works for everyone. Your health care provider will take the following into consideration when recommending a treatment plan:

Pregnancy can have a big impact on thyroid function, and hyperthyroidism is more common during this time. If you have a family history of endocrine disorders, be sure to talk with your OB/GYN physician during one of your routine appointments.

A common first line of treatment for hyperthyroidism is beta blockers, which help manage symptoms such as rapid heart rate, tremors and anxiety, but don’t treat the underlying condition.

Common treatments to address the cause of hyperthyroidism include antithyroid drugs to reduce thyroid hormone production and radioactive iodine therapy to help destroy overactive thyroid cells.

Thyroid surgery may be recommended to remove all or part of the thyroid gland if other treatments haven’t worked. Lifelong thyroid hormone replacement is needed if the thyroid gland has been removed, to maintain healthy thyroid hormone levels.

Hyperthyroid Symptoms

  • Weight loss: unexplained and rapid weight loss
  • Increased heart rate: palpitations and a rapid heartbeat
  • Nervousness and irritability: feeling anxious or agitated
  • Heat intolerance: sweating or difficulty tolerating heat
  • Tremors: shaky hands or muscle weakness
  • Enlarged thyroid: visibly enlarged thyroid gland (goiter) located in the neck
  • Changes in menstrual pattern: irregular menstrual cycles
  • Fatigue: feeling weak and fatigued
  • Bowel movements: more frequent than normal

Hyperthyroidism Causes

  • Graves disease: This autoimmune disorder is the most common cause of hyperthyroidism by causing the immune system to mistakenly attack the thyroid gland — which leads to an overproduction of thyroid hormone.
  • Overactive thyroid nodules can produce hormones beyond the body’s needs.
  • Inflammation of the thyroid gland, known as thyroiditis, can cause the release of stored hormones.
  • Too much iodine either through diet or medicine can cause hyperthyroidism.
  • Too much thyroid hormone medicine can be a cause.
  • A noncancerous tumor of the pituitary gland also can cause hyperthyroidism.

Norton Now: Care When You Need It

  • Get medical care when and where it works for you.
    • Norton Community Medical Associates primary care is your medical home. More than 35 locations across the Louisville area and Southern Indiana means there’s an office close to home, work or school. Your primary care physician knows you and your health and performs annual checkups to stay ahead of any emerging conditions. Our doctors and nurse practitioners connect you to the full Norton Healthcare system, giving you and your family easy access to the area’s leading specialty physicians.
    • More than 15 Norton Immediate Care Centers offer treatment for minor illnesses and injuries. Reserve your spot in line and we’ll text you when it’s time to check in. All Norton Immediate Care Centers are equipped with X-ray machines.
    • Norton Prompt Care clinics have same-day appointments available when you need care for yourself or your family. All locations offer extended weekday and weekend hours. Many are located within Walgreens stores.
    • Norton eCare allows you to visit with a provider via secure video or by simply answering questions online about your symptoms.
    • Emergency care is available for a very serious illness or injury that puts your life in danger. Get treatment 24/7 at nine locations in Louisville and Southern Indiana, including three locations for kids.
  • Medicaid, Medicare and most major commercial insurance plans are accepted.
  • Get test results, renew prescriptions, communicate with your health care provider, get notified if an earlier appointment becomes available and more with your free Norton MyChart account.

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