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Subclinical Hyperthyroidism


Subclinical hyperthyroidism is a condition that develops when the amount of thyroid stimulating hormone (TSH) in your blood is low. TSH is made in the brain and controls how much thyroid hormone is made. Thyroid hormones help control body temperature, heart rate, growth, and weight. Subclinical hyperthyroidism can lead to hyperthyroidism.


Informed consent

is a legal document that explains the tests, treatments, or procedures that you may need. Informed consent means you understand what will be done and can make decisions about what you want. You give your permission when you sign the consent form. You can have someone sign this form for you if you are not able to sign it. You have the right to understand your medical care in words you know. Before you sign the consent form, understand the risks and benefits of what will be done. Make sure all your questions are answered.

You may need extra oxygen

if your blood oxygen level is lower than it should be. You may get oxygen through a mask placed over your nose and mouth or through small tubes placed in your nostrils. Ask your healthcare provider before you take off the mask or oxygen tubing.

A heart monitor

is an EKG that stays on continuously to record your heart's electrical activity.


You may need to eat more to give your body the extra energy it needs. Foods high in protein and calories will help prevent weight loss. A healthcare provider may help set up a meal plan with you.


  • Anxiety medicine may help you feel calm and relaxed.
  • Antithyroid medicine may help decrease your thyroid hormone level.
  • Heart medicines may help slow your heart rate.


  • Blood tests may be done to monitor your thyroid hormone level.
  • A sample of your thyroid gland tissue may show what is causing your condition and the best treatment plan for you.
  • A thyroid scan may show how well your thyroid is working. Radioactive liquid is put into your IV or is given to you to drink. The part of your thyroid gland that still works absorbs the dye. Two to 48 hours later, healthcare providers use a machine called a scintillator to take pictures of your thyroid.
  • An x-ray may be done to check your lungs and heart.
  • An EKG records your heart rhythm and how fast your heart beats.


  • Radioactive iodine is given to damage or kill some thyroid gland cells. This may decrease the amount of thyroid hormone produced. Tell your healthcare provider if you know or think you are pregnant. This medicine can be harmful to an unborn baby.
  • Surgery may be done to remove all or part of the thyroid gland.


Even after successful treatment, you may still have signs and symptoms or they may return. Without treatment, subclinical hyperthyroidism can worsen and turn into hyperthyroidism. You may lose weight, have a hard time falling asleep, and feel nervous and restless. You may also have shortness of breath and an abnormal heartbeat. You may also develop heart disease, low bone density, and other medical problems.


You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your caregivers to decide what care you want to receive. You always have the right to refuse treatment.

© 2016 Truven Health Analytics Inc. Information is for End User's use only and may not be sold, redistributed or otherwise used for commercial purposes. All illustrations and images included in CareNotes® are the copyrighted property of A.D.A.M., Inc. or Truven Health Analytics.

The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.