Induced Thyroid Disorders
What are induced thyroid disorders?
Induced thyroid disorders are conditions that occur after taking certain medicines or having certain treatments. Certain medicines and treatments can cause changes to the amounts of hormones produced by the thyroid gland. The thyroid gland is a butterfly-shaped organ found in the front part of your neck. Thyroid hormones are special chemicals that act as messengers to help control your heart rate, growth, body temperature and other functions. The thyroid hormones also control how your body uses the energy it needs. Having too much or not enough thyroid hormones in your body may cause problems.
What may cause induced thyroid disorders?
Amiodarone:
This medicine is used to treat irregular heart beats. When used for a long time, it may cause thyroid hormone levels in your blood to go too low or too high.
Interferon:
This medicine is used to treat tumors and other diseases, such as hepatitis C. It prevents infection and stops the growth and spread of tumors to other organs. This medicine directly attacks thyroid cells, or may make your own body destroy its thyroid gland. This may lead to high or low amounts of thyroid hormones in the blood.
Lithium:
This medicine treats mental disorders. In people with autoimmune problems, lithium may increase the production of antibodies against thyroid cells and cause hypothyroidism. Rarely, using this medicine for a long time may also cause very high amounts of thyroid hormones in your blood.
Radiotherapy:
This procedure uses radiation as treatment for head and neck tumors, including thyroid gland tumors. Radiation may cause damage to the thyroid cells and may decrease the production of thyroid hormones. Symptoms of hypothyroidism may be seen as early as three months after radiation and last for years.
What are the signs and symptoms of induced thyroid disorders?
You may have signs and symptoms of hyperthyroidism or hypothyroidism. Hyperthyroidism is having too much thyroid hormones in your blood. Hypothyroidism is not having enough thyroid hormones in your blood. The following signs and symptoms may start slowly, and you may not even notice any changes until later:
Hyperthyroidism:
Feel hot and tired, and sweat easily.
Feel nervous, tense, restless, and cannot stay still for long periods.
Have a lump in the front of your neck which may be painful.
Have diarrhea (loose bowel movements) or constipation (dry, hard bowel movements).
Have tremors and fast heart beats even when you are resting.
Have weight loss and always feel hungry even if you are eating most of the time.
Your eyes bulge out more than normal.
Hypothyroidism:
Feel depressed, irritable, or anxious.
Have body weakness, or muscle or joint pains.
Have dry, flaky skin or thin and brittle fingernails or hair.
Have hoarseness or change in voice or speech.
Have too much and too sudden weight gain.
Have sleepiness or problems thinking clearly, such as being forgetful and easily confused.
Have very slow heartbeat and trouble breathing.
How are induced thyroid disorders diagnosed?
You may need any of the following:
Blood tests:
You may need blood taken for tests. These tests tell your caregiver how high or how low the levels of thyroid hormones are in your blood. This information may also be used to see how well any treatments are working.
Biopsy:
This is a procedure where a very small piece of your thyroid gland is taken for tests. A biopsy checks for problems such as thyroid cancer. Your caregiver may use medicine to numb the front part of your neck. A small needle is inserted to get the tissue sample from your thyroid gland. After the sample is collected, a bandage may cover the biopsy area, and the sample is sent to the lab for tests.
Thyroid scan:
This test shows caregivers how well your thyroid is working. Radioactive dye is put into your IV or is given to you to drink. The working part of the thyroid gland absorbs (soaks up) the dye. Two to 48 hours later, caregivers put a machine called a scintillator over your neck. The machine takes pictures showing the areas of your thyroid that absorbed the dye.
Thyroid ultrasound:
This is a test using sound waves to look at your thyroid gland. Pictures of your thyroid gland show up on a TV-like screen.
How are induced thyroid disorders treated?
Treatment depends on your health, age, and the level of your thyroid hormones. Your caregiver may ask you to stop taking medicines that cause problems with your thyroid. You may also need any of the following:
Medicines:
Anti-thyroid medicine:
This medicine decreases the amount of thyroid hormone made by your thyroid gland. This medicine can also cause your thyroid to stop making thyroid hormone completely.
Thyroid hormone:
You are given this medicine to bring your thyroid hormone level back to normal.
Steroids:
Steroid medicine may be given to decrease inflammation, which is redness, pain, and swelling.
Others:
Medicines to treat very fast heartbeats, nervousness, sweating, trembling, and other symptoms may also be given.
Radioactive iodine:
A radioactive form of iodine is given to damage or kill some thyroid gland cells. This may decrease the amount of thyroid hormone made by the thyroid gland. If you are a woman, tell your caregiver if you are or think you might be pregnant or if you are breast feeding. The medicine may be passed on to the baby and cause problems.
Surgery:
Your thyroid gland may need to be removed. This may be needed if you cannot have radioactive iodine medicine. Very young children, breast feeding mothers, and those with thyroid eye disease may need this surgery.
Where can I get more information?
Having induced thyroid disorders may be hard. You and those close to you may feel scared, angry, or sad. These are normal feelings. Talk to your caregivers, family, or friends about your feelings. Contact the following for more information:
American Thyroid Association
6066 Leesburg Pike, Suite 550
Falls Church, VA 22041
703-998-8890
800-849-7643
www.thyroid.org
