Hyperthyroidism
A gland in the fast lane
Who would think that a gland shaped like a delicate butterfly could cause such a commotion? But it can, including a host of problems ranging from bulging eyes to a dangerously high and erratic heartbeat.
The thyroid gland, located in the front part of the neck towards its base, produces thyroid hormones. These hormones have the power to increase the rate of metabolism and body temperature and wreak havoc on the cardiovascular, nervous, metabolic, and endocrine systems. Too much thyroid hormone and you have hyperthyroidism -- a thyroid that stays in the fast lane.
Common symptoms of hyperthyroidism include nervousness, increased sweating, heat sensitivity, and fatigue. Not only does hyperthyroidism run in families, it also seems to be connected to several other conditions. Graves' disease is an autoimmune disease that provokes excessive thyroid production. Also, the pituitary gland -- the thyroid's "boss" -- can malfunction and mistakenly tell the thyroid to produce too much thyroid hormone, although this is rare. Iodine depletion followed by iodine repletion can provoke high-thyroid production as well.
Hyperthyroidism is a relatively treatable condition, but left unattended, even moderate hyperthyroidism can have a profound effect on the body. Treatments aimed at reducing the excess thyroid activity include medications, radioactive iodine, and surgery.
Pronunciation
HY-per-THY-royd-izm
Detailed Description
Hyperthyroidism is a state where excess thyroid hormone is produced. The syndrome of features produced by this excess is called thyrotoxicosis. These features include the following:
- Weight loss -- even with increased hunger
- Muscle deterioration and weakness
- Tremors
- Fatigue
- Shortness of breath
- Erratic and rapid heartbeat
- Breast enlargement
- Irritability and anxiety
- Bulging eyes (exophthalmos)
- Increased sweating and intolerance of heat
- Fine, straight hair
- Clubbed fingers
- Localized myxedema (skin thickening)
- Warm, moist skin
If not managed, hyperthyroidism can bring on these symptoms, or perhaps worse: episodes called "thyroid storms," which can be fatal. This crisis can come about when too much thyroid hormone floods the body. In a thyroid storm, all systems are on overdrive, resulting in body temperature as high as 106F (41C), excessively increased heart and respiratory rates, coma, and possibly death.
This major crisis aside, even day-to-day living with hyperthyroidism can be uncomfortable and jeopardize stable cardiac and metabolic functions. Too much thyroid hormone and most of your systems will feel it. If the thyroid gland is working overtime, so is just about every other part of your body.
Hyperthyroidism is seen in several different disease states, including the following:
- Graves' disease: an autoimmune disease that provokes excessive thyroid production and instigates the creation of abnormal antibodies. Goiters (see below) and eye problems commonly appear in Graves' disease patients.
- Toxic adenoma: a condition in which benign growths cause solitary nodules (growths) in the thyroid gland. It usually occurs in older adults.
- Pituitary gland malfunction: can mistakenly send chemical messages to the thyroid and trigger it to overproduce thyroid hormone. This stimulation rarely occurs, but is sometimes an indication of a tumor on the pituitary gland.
- Goiters: an enlargement of the front of the neck due to an inflamed and enlarged thyroid gland.
- Iodine-induced hyperthyroidism: rare, but follows the natural course of other hyperthyroid conditions. Diet or medications may be at the bottom of this turn of events and need to be investigated by a health professional.
Though anyone from a child to the very old can suffer from hyperthyroidism, most people are diagnosed with this condition in their 30s and 40s. About one in 1,000 women have the condition, whereas only one in 3,000 men have hyperthyroidism.
Treatment of hyperthyroidism usually follows a standard course. Most often, people are prescribed anti-thyroid-producing drugs like Tapazole (methimazole) or PTU (propylthiouracil). They stay on this medication for about three to 12 months in the hope the condition will pass. If patients continue to test with high thyroid levels then they are usually advised to then undergo a procedure -- either radioactive iodine treatment or surgery -- to curtail the functioning of their thyroid gland.
These two procedures are imperfect in that they often overshoot the intended goal, leaving the thyroid crippled and under-producing. When this happens, the patient needs to compensate for the artificially induced hypothyroid condition by taking medication.
Characteristics of Hyperthyroidism
Hyperthyroidism is a condition that causes a wide range of systems. It can have a profound impact on the cardiac, metabolic, neurological, endocrine, and muscular systems. As the thyroid gland produces more and more thyroid hormone, the body gets messages to speed up and responds accordingly. Patients notice a variety of signs and symptoms that include erratic heartbeat, palpitations, irritability, nervousness, sweating, and fatigue.
How Common Is Hyperthyroidism?
Approximately one in every 2,000 Americans is affected by hyperthyroidism. Found in every age group, the condition is most common between ages 20 and 50. Approximately three times more females than males experience this condition.
What You Can Expect
Two causes of hyperthyroidism -- Grave's disease and subacute thyroiditis -- may on occasion spontaneously improve. Untreated, hyperthyroid disease can have a mild to profound impact on cardiac, metabolic, neurological, endocrine, and muscular systems. In some cases, patients live undiagnosed and untreated with a low level of fatigue, weight loss, and muscle wasting. Always the first ones to feel warm in a room, they are perhaps considered a bit anxious and irritable on a day-to-day basis or considered "high-strung."
In severe cases, untreated hyperthyroid disease can cause extreme damage and deterioration to the body and perhaps even trigger a condition called a "thyroid storm." These episodes can be fatal. They come about when too much thyroid hormone floods the body. All systems are on overdrive, resulting in body temperatures as high as 106F (41C), excessively increased heart and respiratory rates, coma, and possibly death.
With treatment and consistent management, the symptoms of hyperthyroidism can be lessened or eliminated and thyroid hormone levels reduced to normal. If a person undergoes radioactive iodine treatment or surgery, the outcome is often the opposite condition -- hypothyroidism. This condition needs to be managed and treated as well.
Established Causes
The exact cause of hyperthyroidism is unknown.
Theoretical Causes
There are several theoretical causes of hyperthyroidism:
- Graves' disease: an autoimmune thyroid disorder that causes overproduction of thyroid hormone
- Autonomous toxic adenomas of the thyroid: growths on the thyroid gland independent of external factors
- Subacute thyroiditis: may be due to infection and marked by a moderately enlarged, tender thyroid gland
- Jod-Basedow disease: an iodine-induced state that could be due to iodine repletion after deprivation
- Thyrotoxicosis factitia: due to excessive ingestion of thyroid hormone
- TSH (thyroid-stimulating hormone) hypersecretion by the pituitary gland
- Hashimoto's thyroiditis: an autoimmune disease directed against thyroid antigens
- Thyroid nodules or tumors
Risk Factors
The exact cause is unknown, but certain factors put a person at higher risk:
- Family history of the disease
- Being a woman
- Autoimmune disorders
- Iodine repletion after deprivation
- Stress
Risk factors are traits or behaviors that may make you statistically more likely than others in the general population to have a certain condition. They are not necessarily "causes" of the condition.
Symptoms
- Weight loss -- even with increased hunger
- Muscle deterioration and weakness
- Tremors
- Shortness of breath
- Erratic and rapid heartbeat
- Nervousness
- Weakness and fatigue
- Goiter
- Loose stools
- Breast enlargement
- Irritability and anxiety
- Bulging eyes (exophthalmos)
- Increased sweating and intolerance of heat
- Fine, straight hair
- Clubbed fingers
- Localized myxedema (skin thickening)
- Warm, moist skin
Conditions That May Be Mistaken for Hyperthyroidism
Other diseases or conditions could potentially display the same symptoms as hyperthyroidism, thus confusing the diagnosis. They include the following:
- Anxiety
- Malignancy
- Diabetes
- Pregnancy
- Menopause
- Pheochromocytoma (an adrenal-system tumor)
- Acromegaly (a disease that causes elongation of bones)
- Bipolar disorder
- Substance abuse
How Hyperthyroidism Is Diagnosed
Your physician will review your medical history and perform a physical examination. A series of laboratory blood tests will usually be performed. Your physician may perform a thyroid scan via X-rays or ultrasound if nodules are present.
Hyperthyroidism tends to run in families, and hereditary autoimmune diseases can also cause the disease. If either is present in your family, call these factors to the doctor's attention if you or a family member undergo evaluation for possible hyperthyroidism.
Lab tests
Many different tests are used to aid in the diagnosis of hyperthyroidism. Most are blood or urine tests designed to measure either various hormones or cofactor (iodine) levels, including the following:
- Thyroid-stimulating hormone (TSH) in blood (low)
- Free thyroxine (T4), a thyroid hormone, in blood (high)
- Free triiodinethyronine (T3), another form of thyroid hormone, in blood (high)
- Abnormal antibodies -- points to Graves' disease
- Iodine uptake by thyroid gland (using radioactive iodine)
Imaging
- Radioimmunoassay is a very sensitive technique for measuring the level of a desired substance. It is more sophisticated than other, more common techniques for measuring hormone or protein levels.
Radioactive iodine uptake measurements gauge how well the thyroid gland gathers and retains iodine. You will be given a radioactive iodine capsule or liquid and your thyroid gland will be scanned at regular intervals (at two, six, and 24 hours). This test reveals how the thyroid stores and dispenses iodine, a precursor to the production of thyroid hormone. - X-ray and ultrasound tests evaluate the thyroid's shape, composition, and positioning.
In Graves' disease, the thymus may occasionally be enlarged. This can be determined with a chest X-ray. X-rays capture a picture of the thyroid after you have taken radioactive iodine, either orally or intravenously. Remember not to take multivitamins, cough syrup, iodized salt, salt substitutes, seafood, or other medications for three days prior to the scan. Check with your doctor and follow his or her instructions.
Ultrasound procedures do not use radioactive iodine. This technology "reads" the thyroid gland by bombarding it with high-frequency sound waves, which then transform into images on the operator's screen.
Goals of Treatment
While hyperthyroidism has no cure, it can be treated with medication and/or procedures like radioactive iodine therapy or surgery. Managing this condition often includes paying closer attention to special dietary needs and lifestyle issues, such as avoiding excessive exertion. Treatment goals include normalizing thyroid hormone levels, stabilizing cardiac function (with beta-blocking drugs, if necessary), and treating exophthalmos (bulging eyes) if present.
Treatment Overview
Treatment for hyperthyroidism may involve taking drugs to suppress thyroid activity, undergoing radioactive iodine therapy to limit the thyroid gland's capability, or undergoing surgery to remove a portion of the gland. All treatment options aim to reduce the amount of thyroid hormones being released into the body and prevent accompanying complications.
Drug therapy
The most commonly prescribed drugs include the following:
- PTU (popylthiouracil)
- Tapazole (methimazole)
Tapazole (methimazole) and PTU (propylthiouracil) interfere with synthesis of thyroid hormone. They should be taken at the same time every day and with meals. Check with your doctor to see if you can eat iodized-salt products. Side effects include dermatitis, agranulocytosis (an abnormal blood condition), and hepatotoxicity (liver failure). These are serious conditions, so be sure to discuss all possible side effects with your physician.
- Radioactive iodine treatment may be required if medications cannot control your overactive thyroid gland. Administered orally, radioactive iodine settles in the thyroid and destroys some of the gland's tissue. In this way, hormone levels are reduced because the production capability of the thyroid gland has been reduced. Dosage is difficult to determine, so sometimes it takes more than one procedure to curtail the hormone production. Also, you may not notice lowered thyroid levels for up to six months after your first procedure. Often, iodine therapy overshoots its mark and results in some degree of hypothyroidism.
Other drug choices
- Carbimazole (used in Europe)
- Iodine (Lugol's iodine solution)-- before thyroid surgery or for thyroid storm
Beta-blockers are drugs that lower blood pressure and decrease the heart rate, helping relieve the symptoms of thyroid excess. They include the following:
- Corgard (nadolol)
- Inderal (propranolol)
- Lopressor (metoprolol)
- Tenormin (atenolol)
Surgery
Surgeons can remove part of the thyroid gland, intentionally making it less effective. During this procedure, known as thyroidectomy, more than 80% of the thyroid is usually taken away. A preoperative thyroid medication clears the gland of excess hormone so it doesn't flood the system upon surgical removal. Iodine preparations are also sometimes prescribed.
After a thyroidectomy, be aware of the following:
- Don't strain your neck following surgery; support your head with a pillow when resting or with your hands behind your neck when turning your head.
- If you have difficulty swallowing or breathing following surgery, contact your doctor immediately.
- You will most likely be placed on a soft diet for a few days; cold drinks and ice can help recovery.
- Sutures will be removed before you are discharged from the hospital, and your voice will be checked for hoarseness after surgery; there is a slight risk to the laryngeal nerve as well as permanent voice change with this type of surgery.
- You will continue being monitored for hyper- and hypothyroid conditions in order to ascertain the result of the surgery.
Follow-up treatment
Whatever your treatment plan entails, be sure to stay in touch with your doctor for important follow-up visits. Your thyroid hormone levels need to be checked about twice a year and any medications adjusted accordingly.
A typical treatment might include the following:
- Biannual thyroid tests
- If radiotherapy was done, test thyroid function at six weeks, 12 weeks, six months, and annually thereafter
- Antithyroid therapy for three months to a year
Appropriate Healthcare Setting
Hyperthyroidism is generally treated on an outpatient basis. However, in the event of a crisis like a thyroid storm, you would be hospitalized and watched closely. Hospitalization is also necessary if a thyroidectomy is performed.
Healthcare Professionals Who May Be Involved in Treatment
A number of health professionals participate in managing this disorder, including specialists. They can include the following:
- Family physicians
- General internists
- Pediatricians
- Geriatricians
- Clinical endocrinologists
- Thyroidologists
- Ophthalmologists
- General surgeons
Activity & Diet Recommendations
Activity
Long, strenuous exercise can aggravate a hyperthyroid condition. Try to rest, especially if your thyroid levels are still elevated.
Diet
Eat a well-balanced diet that keeps up with your increased metabolism. The thyroid hormone has revved up your digestive system, and you will most likely feel hungry frequently. Eat enough calories to counteract the increased need for food.
Because metabolic demands can be so great, you may need to consult with a nutritionist. Try not to eat or drink foods containing dye (yellow or red in particular), artificial preservatives, or caffeine; some experts believe they can make you feel irritable.
If your eyes have been affected by the hyperthyroid condition and are bulging, check with your doctor. Lowering your fluid and salt intake can help reduce the pressure on your eyes.
Quality of Life
Although hyperthyroidism is a chronic condition, it can be managed and controlled with medication, iodine therapy, and/or surgery. For the most part, your life can go on with little change, even though you must continue to be on the alert for signs and symptoms of elevated thyroid hormone levels. Be aware that strenuous activity can effect these levels. If you are taking antithyroid medications, however, certain rare, life-threatening side effects require immediate treatment. See your health practitioner for a full discussion of these issues.
Try to withdraw from stressful situations that provoke anxiety. You have a condition that is aggravating your nervous system, so try to be kind to yourself.
Considerations for Women
Pregnancy
Because women with hyperthyroidism have an increased risk of miscarriage and premature delivery, special considerations must be followed.
Doctors usually do the following:
- Use PTU (propylthiouracil) rather than Tapazole (methimazole)
- Prescribe the minimal amount of PTU (propylthiouracil) in order to avoid treatment-induced hypothyroidism
- Notice that thyroid condition improves during pregnancy and then returns postpartum
- Do not consider using radioactive iodine therapy; it can cross the placenta and make the fetus hypothyroid
Considerations for Children and Adolescents
Infants of two to three months can be treated with antithyroid medications. Most children are also treated with the same types of medications used for adults. Procedures like radioactive iodine therapy or surgical removal of the thyroid are rarely done on children.
Children with hyperthyroidism can also show signs of the following:
- Accelerated growth
- Eye abnormalities
Considerations for Older People
It is difficult to diagnose elderly people suffering from hyperthyroidism because the symptoms are sometimes less pronounced and often confused with features of natural aging. Cardiac malfunctions and fatigue-- two symptoms of hyperthyroidism-- are often attributed to other causes.
Along with the usual symptoms of hyperthyroidism, elderly people may also experience confusion, dizziness, failure to thrive (with a refusal to eat or drink), and such mental issues as dementia, depression, paranoia, hypochondria, psychosis, or suicidal thoughts. Hyperthyroid conditions can cause an increased tendency to fall and incontinence in elderly people.
When used, thyroid-suppressing drugs are started at a low dose and, when necessary, slowly increased in dosage.
Herbs
Bugle weed: This herb has a long folk history as a treatment for hyperthyroidism, but it's not a cure. Its effects are mild, and are best used in combination with mainstream pharmaceuticals.
Meditation, biofeedback, and visualizations won't cure hyperthyroidism, but they can help you cope until medication gets the condition under control.1Duke, James. The Green Pharmacy. Emmaus, PA: Rodale Press, 1997.
Self-Care Measures
- If you smoke, stop. Smoking increases the risk of hyperthyroidism.
- Avoid stimulants. They may worsen hyperthyroidism. Avoid caffeine in coffee, tea, cocoa, chocolate, and stimulant-containing drugs like decongestants.
- Take care of your eyes. If you experience bulging eyes from the elevated thyroid hormone levels, see an ophthalmologist regularly and protect your eyes by wearing sunglasses, administering eye drops if prescribed, limiting your fluid and salt intake, and sleeping in an elevated position.
- Know your family history. Hyperthyroidism may be hereditary. Know your family history and make sure your doctor is aware of it, too. This may help early detection of the disease.
Websites & Organizations
American Thyroid Association
Endocrine-Metabolic Service
Walter Reed Army Medical Center
Washington, DC 20307-5001
Phone: 202-882-7717 or 800-542-6687
Fax: 202-882-7813
Endocrineweb.com
Mayo Clinic
200 First Street, SW
Rochester, MN 55905
Phone: 507-284-4738
The National Graves' Disease Foundation
2 Tsitsi Court
Brevard, NC 28712
Phone: 828-877-5251
NIDDK Office of Information
National Institutes of Health
NIH Building 31, Room 9A04
Bethesda, MD 20892
Phone: 301-496-3583
Thyroid Federation International
Thyroid Foundation of America
Box RD, Ruth Sleeper Hall RSL350
40 Parkman Street
Boston, MA 02114-2698
Thyroid Foundation of Canada
The Thyroid Society
7515 South Main Street, Suite 545
Houston, TX 77030
Phone: 800-THYROID (800-849-7643) or 713-799-9909
Email: help@the-thyroid-society.org
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