Do you have an overactive thyroid?

The thyroid is a small butterfly-shaped endocrine gland just above the collarbone in the front of the neck. It makes thyroid hormone, a substance that controls our metabolism — the chemical processes in the body that allow us to function every day. Hyperthyroidism occurs when the thyroid makes too much thyroid hormone. This can cause an increased metabolism, with accompanying signs and symptoms such as:

• Unintentional weight loss— even when appetite and food intake stay the same or increase

• Rapid and sometimes irregular heartbeat — more than 100 beats a minute

• Pounding of the heart — palpitations

• Nervousness — anxiety and irritability

• Tremor — usually in the hands and fingers

• Sweating— increased sensitivity to heat

• Changes in menstrual patterns and difficulty getting pregnant

• More frequent bowel movements

• Fatigue, muscle weakness

• Difficulty sleeping

• Skin thinning

• Fine, brittle hair and hair loss

Some patients may have an enlarged thyroid, known as goiter. The eyes can also become dry or red, and if severe, the eyeballs can seem to protrude and cause a distinctive “stare.” If not treated for a long time, patients can develop heart problems leading to congestive heart failure, where the heart cannot circulate enough blood throughout the body.

Patients can also get osteoporosis with weak, brittle bones that are prone to break.

Hyperthyroidism also places patients at risk for thyroid storm, a sudden escalation of symptoms where heart rate and body temperature may increase to dangerously high levels. This is an emergency and patients should seek immediate medical care if this occurs.

If hyperthyroidism is suspected, blood tests are done to check thyroid hormone levels. Typical findings are a low TSH (thyroid stimulating hormone) with high free T4 and free T3. Antibody tests, a neck ultrasound and a thyroid scan can also be done.

The most common cause of hyperthyroidism is Graves’ disease, an autoimmune disorder where antibodies produced by the immune system stimulate the thyroid to produce too much thyroid hormone.

Another cause is a hyperfunctioning thyroid nodule or adenoma, a noncancerous (benign) lump that can cause an enlargement of the thyroid. Hyperthyroidism occurs when one or more adenomas produce too much thyroid hormone.

Sometimes the thyroid can become inflamed causing thyroiditis where excess thyroid hormone stored in the gland leaks into the bloodstream. If painful and tender, treatment includes pain medications and sometimes antibiotics. Some types of thyroiditis are painless.

Treatments for hyperthyroidism

Treatment for hyperthyroidism includes anti-thyroid medications such as methimazole or propylthiouracil. Symptoms usually begin to improve in several weeks to months, with treatment typically continuing for at least a year and often longer. Although rare, some patients can have allergies or become more susceptible to infection, so only take these medications under the supervision of a doctor.

Radioactive iodine (RAI) is another treatment that causes the thyroid gland to shrink. It is taken by mouth as a single dose and symptoms usually subside within several months. RAI may also cause the thyroid to become underactive causing hypothyroidism and patients may eventually need to take medication every day to replace the lacking thyroid hormone.

Surgical removal of the thyroid is also an option for patients who cannot tolerate anti-thyroid drugs, if they cannot have RAI, or if they have very large goiters. It is a common misconception to treat thyroid disease by ingesting more iodine-containing foods such as seafood and seaweed. These should be avoided because iodine further increases the production of thyroid hormone, making symptoms worse. This is also aggravated by the intake of too much iodized salt.

If you experience any of the signs and symptoms associated with hyperthyroidism, see your doctor. Hyperthyroidism can mimic other conditions and it is important to let your doctor know about all the changes you have experienced.

Remember to see your doctor regularly as advised so your condition can be monitored.