Your thyroid plays a big role in many of your body’s main functions. As an endocrine gland, it produces and releases hormones affecting your breathing, heart rate, digestion, and even your mood.

Thyroid diseases occur when your thyroid over- or underproduces these hormones. Mary Carroll, MD, an endocrinologist at Summit Health, answers questions about thyroid diseases called hypothyroidism and hyperthyroidism. She explains the causes, symptoms, and treatments for these common conditions.


What is your thyroid, and why is it important for your body?

The thyroid is a small butterfly-shaped gland in the front of your lower neck. Its job is to produce thyroid hormones that help control how your body uses energy. The thyroid is vital to most of your body’s functions, and if your thyroid isn’t working properly, neither will you.


What is hypothyroidism?

If your thyroid does not produce enough thyroid hormone, you could have hypothyroidism, also called underactive thyroid.


What are the common symptoms of hypothyroidism?

When left untreated, common symptoms of hypothyroidism may include:

· Fatigue

· Weight gain

· Dry skin

· Constipation

· Changes in hair

· Feeling cold


What causes hypothyroidism?

In the U.S., hypothyroidism is most commonly caused by an autoimmune disorder called Hashimoto’s thyroiditis. In people with Hashimoto’s thyroiditis, the immune system inappropriately creates antibodies that can attack the thyroid gland. If the antibodies are successful, After months to years, hypothyroidism can result.

Other causes of hypothyroidism can include thyroid surgery, pituitary diseases, and certain medical therapies used to treat cancer.


What is hyperthyroidism?

An overactive thyroid, or “hyperthyroidism,” occurs when the thyroid gland overproduces thyroid hormone beyond the body’s needs.

What are the common symptoms of hyperthyroidism?

Common symptoms of hyperthyroidism may include:

· Fatigue

· Racing heart

· Tremor of the hands

· Increased anxiety

· Weight loss

· Swelling of the neck

· A feeling of heat intolerance


What causes hyperthyroidism?

The most common cause of hyperthyroidism is another autoimmune condition called Graves’ Disease. Other causes can include “hot” or overactive toxic growths on the thyroid, taking too much medication for the treatment of hypothyroidism, and thyroiditis.

Thyroiditis refers to a temporary inflammation of the thyroid gland. The cause of thyroiditis often cannot be determined, but there are several known triggers. These include the delivery of a baby, an upper respiratory virus, and a rare side effect of certain medications.


How are hypothyroidism and hyperthyroidism diagnosed?

Both conditions are diagnosed with blood tests, including the thyroid-stimulating hormone (TSH) test. Imaging studies such as ultrasound or a nuclear scan may also be useful.


What is thyroid-stimulating hormone?

TSH, also known as thyrotropin, is produced by your pituitary gland. TSH controls the release of thyroid hormones from your thyroid.

Measuring your TSH levels is the most accurate and reliable blood test to determine thyroid function. Factors affecting the TSH test result other than the thyroid gland status or thyroid medication dose can include pregnancy, advanced age, certain medications, and other underlying health conditions.


What are target TSH levels?

The target TSH level for most people is between 0.5 and 4.5 milli-international units per liter. This target range may vary depending on the lab assay and your health history. TSH levels that are too high or too low may indicate a thyroid problem.

A low TSH level typically indicates that a person is either overproducing thyroid hormone, also known as hyperthyroidism, or is on too high of a dose of thyroid hormone medication. A high TSH level indicates that your body is not making enough thyroid hormone, resulting in hypothyroidism, or if you are on thyroid hormone medication, the dose is too low.


How is hypothyroidism treated?

Hypothyroidism is usually treated by taking a daily hormone replacement tablet called levothyroxine. Levothyroxine is a medication taken as an oral tablet that replaces the amount of hormone that your thyroid is not making.

Levothyroxine dosages can be individualized and adjusted according to your lab results to achieve a normal TSH level for you. It’s important to take your thyroid medication as prescribed in the morning, separated properly from food and other drugs and supplements.

It’s also important to have your TSH tested periodically to determine if your dose or how you take your medication needs to be adjusted. There are no evidence-based dietary or lifestyle modifications otherwise recommended for managing hypothyroidism.


How is hyperthyroidism treated?

The treatment of hyperthyroidism depends on the cause and on the individual patient. Treatments used in the management of hyperthyroidism include anti-thyroid medications, radioactive iodine, radiofrequency ablation, or thyroid surgery.


When should I be referred to an endocrinologist?

You should see an endocrinologist when goal TSH levels cannot be achieved or maintained with success. Referral is also recommended for women with hypothyroidism who are trying to conceive or are pregnant.


Talk openly with your health care provider about your symptoms and any concerns or questions regarding hypothyroidism and its treatment. Through these conversations and shared decision-making regarding dosage and interval of follow-up visits, you can find the best treatment plan for you