Understanding Hyperthyroidism

Hyperthyroidism is a condition in which your thyroid gland makes too much thyroid hormone. Since thyroid hormone affects nearly every organ, tissue, and cell in your body, hyperthyroidism can interfere with most of your body's functions. Fortunately, there are a variety of reliable treatments available for hyperthyroidism, and with the proper care, you can lead a normal, healthy life.

Remember, no single source can answer all of your questions or replace speaking with doctors, nurses, and other members of the healthcare team. If you have any questions or concerns about thyroid or thyroid disorders, please check with your doctor.

Your Thyroid---The Basics

Your thyroid is a gland located at the base of your neck, just below your Adam's apple. It is shaped like a butterfly-each "wing," of lobe, of the thyroid lies on wither side of the windpipe.

The amount of thyroid hormone made by your thyroid gland is adjusted by another gland called the pituitary, as well as a part of your brain called the hypothalamus.

The pituitary gland makes hormones that control many other glands in your body.
The hypothalamus helps the pituitary control many of your glands, as well as helping to control other bodily functions, such as thirst, hunger, sleep, and body temperature.

The thyroid gland, pituitary gland, and hypothalamus all work together to control the amount of thyroid hormone in your body. With the pituitary controlling most of the action, these structures work in a way that is similar to the way a thermostat controls the temperature in a room.

For instance, just as the thermometer in the thermostat senses the temperature of a room, your pituitary constantly senses the amount of thyroid hormone in your blood. If there is not enough thyroid hormone, your pituitary senses the need to "turn on the heat." It does this by releasing more thyroid-stimulating hormone (TSH), which signals and releases the hormone directly into your bloodstream and restores the amount of thyroid hormone in your blood to normal.

Your pituitary then senses that there is just the right amount of thyroid hormone in your body. With your thyroid hormone levels now restored to normal, your pituitary slows its production of TSH back down to normal.

Hyperthyroidism is a fairly common thyroid disorder, and results from too much thyroid hormone being made and released into your bloodstream. This can be caused by a number of things, including:

• Graves' Disease--Graves' disease is a condition in which the immune system causes the thyroid gland to produce too much thyroid hormone. On average, women are five times more likely than men to have this disease.
  
• Thyroid Nodules--Hyperthyroidism caused by nodules simply means that there are lumps in the thyroid gland that are overproducing thyroid hormone.
• Overreplacement of Thyroid Hormone--A patient receiving thyroid hormone replacement therapy for hypothyroidism and given too high a dose (or too much thyroid hormone) can become hyperthyroid.
  
• Postpartum Thyroiditis--This is a condition that occurs after giving birth and may include both hyperthyroidism and hypothyroidism. Postpartum thyroiditis can be temporary condition or it can develop into long-term hypothyroidism.

Having too much thyroid hormone in your blood causes your whole body to speed up. Your heart beats faster, you may feel nervous or jittery, you may be described by others as "irritable," and you may lose weight unexpectedly. Over the long term, untreated hyperthyroidism can cause very serious health problems. Therefore, it is very important that hyperthyroidism be identified and treated as soon as possible.

Identifying Hyperthyroidism

Not everyone with hyperthyroidism will have the same signs and symptoms. In fact, some people may have only a few, and some people may not have any. Moreover, some symptoms are often mistaken for the other conditions. Keeping that in mind, the following is a list of possible signs and symptoms that you may experience if you have hyperthyroidism.

• Nervousness and irritability
  
• Sleep disturbances (for example, insomnia)
  
• Fast, irregular heartbeat
  
• Shortness of breath, especially with exercise
  
• Heat intolerance and increased sweating
  
• Shaky hands (tremor)
  
• Weight loss
  
• Changes in appetite (usually increased appetite)
  
• More frequent bowel movements
  
• Tiredness and muscle weakness
  
• Thyroid enlargement (goiter)
  
• Menstrual problems (decreased menstrual flow)
  
• Impaired fertility
  
• Eye irritation, double vision, bulging eyes

Making a Diagnosis

If your doctor suspects you have hyperthyroidism, he or she will probably investigate the following things.

Your Personal and Family Health History

Thyroid disorders can often be hereditary. If you have a family member, like your mother or father an aunt or uncle, or your brother or sister, who has a thyroid disorder (especially of it is autoimmune), your chance of developing one may be higher.

Your Likelihood of Developing a Disorder

Some individuals are more likely than others to be hyperthyroid. You are at an increased risk if you:

• Are a woman, 30 years or older
  
• Are pregnant or have given birth in the last 6 months*
  
• Have other autoimmune conditions, such as:
  
• Addison's disease
  
• Type 1 Diabetes
  
• Pernicious anemia
  
• Rheumatoid arthritis
  
• Systemic lupus erythematosus (SLE or lupus)

*Note: If you've had a baby in the past 6 months, you may be at a higher risk for developing hyperthyroidism due to autoimmune thyroid disease.

Your Physical Condition
Your doctor will probably give you a physical exam to look for the signs and symptoms of hyperthyroidism.

In particular, there is one very reliable sign that your doctor will look for: enlargement of the thyroid, which is called a goiter. A goiter is a common physical sign of thyroid disorders. Your doctor will examine your neck, pressing on, or palpating, the area where your thyroid is located in order to determine if a goiter is present.

Your doctor will also examine your thyroid gland to determine if there are thyroid nodules present. Thyroid nodules are lumps in the thyroid gland that can result in too much thyroid hormone in your bloodstream. Sometimes, but very rarely, nodules can be cancerous.

In addition, your weight, blood pressure, and pulse will be measured.

Your doctor may examine your eyes, skin, heart, and nervous system, as well. All of these are affected by hyperthyroidism.

Your Laboratory Results

Your doctor will likely order blood tests to find out how your thyroid gland is functioning. The best single test is the TSH test. If your TSH level is lower that normal, it is very likely that you have hyperthyroidism. Your doctor will probably measure your thyroid hormone levels as well, in order to determine the severity of your hyperthyroidism. If your TSH level is low and your thyroid hormone levels are normal, you may have a mild form of hyperthyroidism, called subclinical hyperthyroidism.

Other tests that your doctor may order are:

• Thyroid antibody test. This test will help your doctor find out if your immune system is affecting your thyroid function (as in Graves' disease)
  
• Radioactive iodine uptake test. Radioactive iodine is a substance that you swallow in tablet form. Between 6 to 24 hours later, your doctor uses a special piece of equipment to measure how much of the radioactive iodine your thyroid absorbed. You may also have an image taken of your thyroid called a thyroid scan. Your doctor can use this information as a guide toward a correct diagnosis.

Treating Hyperthyroidism

There are several ways to treat hyperthyroidism: antithyroid drugs, radioactive iodine, and surgery. Your doctor will explain your options, and may recommend a particular course of treatment that seems best suited to your needs and lifestyle.

Antithyroid Drugs

These are medications that you take in tablet form. They slow down your thyroid's production of thyroid hormone. Often, however, your hyperthyroidism will return once the drugs are stopped, and you will need further treatment. In the United States, 2 drugs are available for treating hyperthyroidism: propylthiouracil (PTU) and methimazole (Tapazole). These medications control hyperthyroidism by slowing thyroid hormone production. Some patients have a spontaneous or natural remission with long term use of these drugs usually 12-18 months). These patients will avoid permanent underactivity of the thyroid (hypothyroidism), which often occurs as a result of using the other methods of treating hyperthyroidism.

Antithyroid drugs may cause allergic reactions in 5% of patients who use them, usually during the first 6 weeks of drug treatment. Such a reaction may include rash, hives, fever, or joint pain and after discontinuing the use of the drug, there is no permanent damage.

A more serious side effect, but occurring in only about 2 of 1000 patients during the first 4 to 8 weeks of treatment, is a rapid decrease of white blood cells in the bloodstream. This could increase susceptibility to serious infection. If symptoms such as a sore throat, infection, or fever are noted, they should be reported to your physician and a blood cell count should be done immediately. In nearly every case, when a person stops using the medication, the white blood cell count returns to normal.

Very rarely, antithryoid drugs may cause liver problems, which can be detected by monitoring blood tests. The physician should be contacted if there is yellowing of the skin (jaundice), fever, or abdominal pain.

Radioactive Iodine

Although it may sound alarming, radioactive iodine is a safe and effective treatment for hyperthyroidism. The substance enters your thyroid gland and permanently destroys thyroid cells. That way, those cells can no longer make thyroid hormone. If you undergo this course of treatment, you may become hypothyroid. In that case, you will need thyroid hormone replacement therapy.

The radioactive iodine is given by mouth, usually in capsule form. The radioactive iodine then enters the thyroid cells from the bloodstream and destroys them. Maximal benefit is usually noted within 3 to 6 months, and there is usually no effect for at least 6 weeks.

Although every effort is made to calculate the correct dose of radioiodine for each patient, not every treatment will result in normal thyroid function. Occasionally, hyperthyroidism continues and a second dose of radioactive iodine is needed. More commonly, an underactive thyroid (hypothyroidism) results, and lifelong daily use of oral thyroid hormone replacement therapy is necessary. For the more than 50 years radioiodine has been used, no serious complications have been reported.

Surgery (Total Thyroidectomy)

Your doctor may recommend that part of your thyroid gland be removed by surgery. This procedure is known as a thyroidectomy. Surgery is the least frequently used type of treatment, but may be chosen if you:

• Are pregnant and don't respond or a allergic to antithyroid drugs
  
• Do not wish to have radioactive iodine therapy
  
• Also have thyroid nodule
• Grave's Disease with Eye Manifestations

Although surgery is currently seldom used as treatment of hyperthyroidism, operating to remove most of the thyroid gland may be recommended in the above situations. In such patients, permanent hypothyroidism usually results and lifelong thyroid hormone replacement is required.

Other treatments

A drug from the class of beta-adrenergic blocking agents (block the effect of excess thyroid hormone on the heart) may be used temporarily to control hyperthyroidism symptoms while one of the above treatments becomes effective. This may be the only type of treatment where hyperthyroidism is caused by thyroiditis or excessive ingestion of iodine or thyroid hormone.

Doing Your Part

If you do become hypothyroid and need thyroid hormone replacement therapy, it is very important that whenever you get your levothyroxine sodium prescription refilled, you check to be sure that you are receiving what your doctor ordered. It is a good idea to take the same brand of thyroid hormone that your doctor started you on, because even the same dose of another brand may not deliver the identical amount of levothyroxine sodium. Do not switch brands without checking with your doctor.

If you begin to have symptoms of fatigue, weight gain, or any other signs of hypothyroidism, tell your doctor. You may need a higher dose.

Similarly, if you notice that you have symptoms of hyperthyroidism, there is a chance that your dose may be too high. Make an appointment to see your doctor right away if this occurs.

It is extremely important to get exactly the right amount of thyroid hormone. Too much or too little may place your body at risk for developing other conditions that can affect your health.

Don't ever stop taking your thyroid hormone replacement therapy without talking to your doctor. If you stop taking it, you may continue to feel fine for a while. Nevertheless, your hypothyroid symptoms will likely return.

Maintaining Your Heath

Seeing your doctor for periodic examinations and TSH tests is the best way to keep your thyroid hormone level normal. Over your lifetime, your body's need for thyroid hormone may change, and the safest way to prevent the damaging effects of abnormal amounts of thyroid hormone is to have your doctor measure your thyroid function regularly so that he or she can adjust your dose to meet your current needs.

Final Note

While finding out that you have hyperthyroidism may seem overwhelming, there are very effective treatments available to you. Additionally, finding out as much as you can about your condition can help you communicate with your doctor and address any concerns you may have in deciding which treatment may best fit your particular condition. With your doctor's expertise and your cooperation, you can overcome your thyroid condition and enjoy a normal, healthy life.

Link to American Thyroid Association website