Return To Main Article
Guide To Thyroid Disease
|What Is Hyperthyroidism?
If you have hyperthyroidism it means that your thyroid (picture) is producing too much thyroid hormone. Sometimes referred to as an 'overactive thyroid' it can produce symptoms which make it look like your body is speeding up (the opposite to hypothyroidism). You may eat more, sweat more, have a faster heartbeat, have more bowel movements and feel restless. Every year about 296,000 Americans are diagnosed with hyperthyroidism and it is 10 times more common in women than in men. Some studies even indicate that it could be more prevalent, and that up to 20 in every 1,000 women could have the condition since mild forms may go unnoticed and undiagnosed. As weight loss is a common sign of hyperthyroidism, some people, silly as it might sound, believe patients are lucky to have the condition. As hyperthyroidism can cause problems throughout the body, including the eyes, heart, skin, hair, nervous system and interfere with fertility, this thinking doesn't make sense. Fortunately with drugs and sometimes surgery, hyperthyroidism is largely manageable.
What Are The Signs?
The symptoms of thyroid disease vary depending on how much thyroid hormone is being produced. Too little, for example and the body slows down (hypothyroidism), too much and we become hyper and burn energy faster (hyperthyroidism). The most common symptoms of hyperthyroidism are:
• Weight loss, even though you may be eating more.
• Increased appetite.
• Shaky hands or fingertips.
• Racing heartbeat or palpitations.
• Sweating - when no-one else in the room is.
• Lighter periods.
• Enlarged swelling on the neck called goiters (picture).
• Bulging eyes (picture). The upper eyelids may be higher so that more of the white of your eye is exposed, giving a pop-eyed appearance.
• Diarrhea or more frequent bowel movements.
• Feeling anxious and nervous.
• Fatigue but difficulties sleeping.
• More prone to feeling the heat.
Other symptoms that can occur include:
• Hair loss (picture).
• Plummers nails - the end of the nails rise so that dirt easily goes under them. It usually starts on the 4th finger of each hand and then spreads to the other fingernails and toenails (picture).
• High blood pressure.
• Itching all over your body.
• Nausea or vomiting, but rarely.
• Skin flushes.
• Women who start to suffer irregular periods can develop infertility and have frequent miscarriages.
• Osteoporosis risks factors increase because high thyroid hormone levels can lower bone density. This means you become more prone to fragility fractures, such as a hip fracture.
What Causes It?
This autoimmune disease is the most common cause of hyperthyroidism (70 percent of cases). Graves disease occurs when an abnormal antibody stimulates the thyroid into producing more hormones than it should.
Any inflammation of the thyroid is called thyroiditis. Inflammation can lead to large amounts of stored hormones being released causing temporary symptoms of hyperthyroidism. There are 2 main types of thyroiditis, silent thyroiditis and DeQuevain's thyroiditis. Silent thyroiditis is quite common after childbirth and DeQuevain's is common after a viral infection of the respiratory system. Both usually clear up, sometimes without treatment.
Noncancerous growths (thyroid nodules) can develop on the thyroid and produce excessive amounts of hormones.
Eating Too Much Iodine
Eating excessive amounts of iodine rich foods, including iodized table salt, can promote the condition.
Over-Treatment Of Hypothyroidism
Sometimes people who are receiving thyroid hormone supplements for the treatment of hypothyroidism, can become over-treated triggering hyperthyroidism.
Rare causes of hyperthyroidism include thyroid cancer and ovarian cancer. For more, read about the general causes of thyroid disease.
How Is It Diagnosed?
Your doctor will carry out a physical examination looking for signs of any enlargement around the neck. He will check your reflexes for hyperactivity, and measure your heart rate and take a blood pressure reading. A diagnosis is never given on a physical exam alone. Blood tests will need to be completed to measure the levels of thyroid hormones in your body. These tests are discussed in more detail in our article: thyroid tests. If you have hyperthyroidism your:
• TSH (thyroid stimulating hormone) level is usually low.
• Your T3 and free T4 levels are usually high.
As treatment of the condition is determined by the cause, your doctor may also order a radioactive iodine scan to differentiate between Graves disease and thyroid nodules.
How Is It Treated?
The choice of treatment depends on the individual's situation and cause of their condition. You should be referred to an endocrinologist, who is experienced in treating hyperthyroid patients.
In Europe, the first line of treatment for most women with Graves disease is antithyroid medications. These can be taken long-term to suppress the production of thyroid hormones. The two main drugs used are methimazole (Tapazole) and propylthiouracil (PTU) (and a third in Europe called carbimizole). These pills gradually reduce symptoms, usually within a few weeks. The current standard is take the drugs for a year and then to stop to see if the disease comes back. The disease usually recurs in about 50 percent of cases within 3 to 6 months of stopping. A recurrence is more likely if you smoke, have a large goiter or still have high thyroid-stimulating antibody levels at the end of treatment. The options after a relapse are: go back to taking the pills, undergo thyroid surgery or start radioiodine. The major advantage of continuing antithyroid medications is that they also help treat complications of Graves disease, including eye disease (unlike radioiodine and surgery).
In the United States, the preferred first line of treatment is radioiodine. Radioiodine is a solution that patient drink and it works by destroying the thyroid tissue. It is cheap, effective, safe and easy to administer. The dosage is varied according to the patient and their age (some may take it in one large dose, others may need to take daily smaller amounts over 3 months). Radioiodine works faster than taking antithyroid medications and is not used long-term. Some doctors used it to destroy only enough of the thyroid to make it function normally, while others will completely destroy the thyroid. Most patients end up needing thyroid hormone replacement therapy pills, because they eventually become hypothyroid.
Surgery is only usually considered if drugs and radioiodine do not work. Surgery involves removing part or the entire thyroid in a procedure called a thyroidectomy. Surgery may also be performed if a goiter is large enough to cause breathing or swallowing problems. If a woman wishes to become pregnant in the future, she is likely to be treated with radioiodine or surgery. This is because the waiting time for when it is safe to fall pregnant is much shorter following these treatments, than it is with drugs. Hyperthyroidism is permanently controlled in 90 percent of patients who undergo surgery. However, if the entire thyroid is removed, you will be left hypothyroid which means you will need to take thyroid replacement hormones for life.
Hypothyroidism caused by inflammation generally does not respond well to antithyroid drugs. Instead it is treated with beta blockers medications, which are more commonly used as a treatment for arrhythmia or treatment for high blood pressure. The beta blockers work by relieving symptoms (palpitations, tremors, sweating) within hours, allowing the thyroid time to recover. Calcium channel blockers such as Cardizem can be used to slow down a fast heart beat in patients who can't tolerate beta blockers.
Is There A Cure For Hyperthyroidism?
For people with temporary forms of hyperthyroidism caused by a virus, beta blockers are usually the only treatment required. When the virus clears, the hyperthyroidism is also cured. However, for the majority of patients (who will have Graves disease), treatment is usually needed for life. But, that treatment may be stopped and started. Many patients who are treated with antithyroid medications are able to stop taking their meds after a year or two, and don't start them again until (or if) the conditions recurs. They may last another 2 to 5 years before needing another prescription. As for radioiodine, while it can be effective, finding the right dosage so that you make the person's thyroid as normal as possible is very difficult. Many patients end up being hypothyroid, which means taking pills for life. Surgery to remove the thyroid has the same effect.
Can It Be Prevented?
There are no known ways to prevent a person becoming hyperthyroid.