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Hypothyroidism
Down in the dumps
Feeling a little fatigued? Putting on weight? Muscles aching, getting cold easily? Rather than a run-of-the-mill life, you may have hypothyroidism.
The thyroid is a master gland that releases thyroid hormones, which regulate growth, energy, and heat production throughout the body. Hypothyroidism means you don't produce enough thyroid hormone or it doesn't act effectively. Thyroid hormone is a bit like the gas pedal on a car. Too much hormone secretion sends the engine racing, inducing rapid heartbeat, fever, and sweating. With hypothyroidism, there is too little thyroid hormone, so the engine slows down.
Hypothyroidism can start gradually and may be hard to spot. It may be years before it is diagnosed.
Symptoms such as fatigue, depression, constipation, and weight gain sometimes get discounted as too vague to actually mean anything. Other features include intolerance to cold, muscle aches, and hair loss. In some cases, years of overlooking early stages of hypothyroid can lead to major complications such as severe fatigue, respiratory failure and heart failure. Most hypothyroidism can readily be treated. When the veil lifts and you return to your spunky self, you may realize how many "minor" difficulties there were.
Pronunciation
Hy-po-THY-royd-izm
Synonyms
- Hypometabolism
- Primary hypothyroidism
- Secondary hypothyroidism
- Subclinical hypothyroidism
Detailed Description
Hypothyroidism is a process where there is not enough thyroid hormone or it does not act effectively. The thyroid is one of the body's master glands. It releases thyroid hormones, which regulate energy and heat production throughout the body. In children, this condition can impede growth and development. In adults, hypothyroidism slows metabolism (energy processing), causing a range of signs and symptoms. They can include the following:
- Weakness
- Lethargy
- Intolerance to cold
- Weight gain
- Constipation
- Hair loss
- Muscle and joint aches
- Menstrual irregularities
- Memory loss
- Difficulty concentrating
Hypothyroidism is divided into two categories: primary hypothyroidism and secondary hypothyroidism. Primary hypothyroidism is when the disease occurs as a failure of the thyroid gland itself. It is the most common form of hypothyroidism. Secondary hypothyroidism happens because of a pituitary problem.
Up to 60% of hypothyroidism in the United States is from an autoimmune cause -- when the normal immune defenses of the body attack the thyroid gland. The common form of this autoimmune disease is called Hashimoto's thyroiditis.
Hashimoto's thyroiditis can cause goiter -- a bulge in the front of the neck due to an inflamed thyroid gland. When radioactive iodine or surgery is used to treat an overactive thyroid, too much correction creates an underactive thyroid.
In other cases, drugs like lithium or amiodarone may damage the thyroid. The right amount of iodine is a necessary ingredient for thyroid hormone. Either too much or too little iodine can cause hypothyroidism.
Myxedema coma is a rare and severe result of untreated hypothyroidism. It is a medical emergency that can cause death. Lung infections, stroke, and heart failure can trigger myxedema coma. Primary features are unconsciousness, low body temperature, and slowed breathing.
Hypothyroidism is treated with synthetic or natural thyroid hormone replacement. Thyroid hormone replacement is effective in relieving symptoms, which is gratifying to both patient and doctor.
Characteristics of Hypothyroidism
- Gradual onset that may go unnoticed
- Retardation of development and growth in children
- Slowed metabolism in adults
- Symptoms can be many and may seem vague at first
- Fatigue, cold intolerance, muscle and joint aches, and weight gain are common
- Thyroid hormone replacement is effective
- Thyroid hormone replacement may need to continue indefinitely
- Myxedema coma, an extreme form of hypothyroidism, is a medical emergency
How Common Is Hypothyroidism?
Hypothyroidism occurs in about 1 out of every 4,000 newborns. In adults, it occurs in about 2% of adult women and 0.1% of adult men. It is not common among infants. In adults, it is more common in middle-aged people. Hypothyroidism is five to 10 times more common in women than men.
What You Can Expect
In rare cases, untreated hypothyroidism may lead to myxedema coma, an extreme hypothyroid condition that is a medical emergency. Otherwise, symptoms are likely to continue unless the cause is removed or there is treatment. With treatment, there are generally no complications.
Established Causes
There are two main classifications of hypothyroidism: primary and secondary. If outside influences such as diet, another disease, or certain types of drugs cause malfunction of the thyroid, it is regarded as primary. If suppression of the thyroid gland is due to malfunction or inadequacy of the pituitary gland, it is regarded as secondary.
For primary hypothyroidism:
- Autoimmune
- Hashimoto's thyroiditis
- Overcorrection of hyperthyroidism from surgery or radioactive iodine
- Iodine deficiency or excess
- Drugs (lithium, amiodarone, others)
- Congenital conditions
For secondary hypothyroidism:
- Failure of the pituitary gland to produce a sufficient amount of thyroid-stimulating hormone (TSH)
- Failure of the hypothalamus gland to produce a sufficient amount of thyrotropin-releasing hormone (TRH)
Risk Factors
Following are several risk factors:
- Pituitary or hypothalamus disease
- Thyroid-suppressing medications such as lithium
- Low iodine in the diet (primarily a phenomenon in the developing worlds)
- Neck trauma
- Autoimmune diseases
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
With hypothyroidism, symptoms and signs may vary with the cause and progress of the disease. You may experience any of the following:
- Fatigue
- Lethargy
- General weakness
- Constipation
- Intolerance of the cold
- Dry, scaly skin
- Receding hairline
- Weight gain
- Dull, blank expression
- Slow, sluggish movement
- Menstrual irregularity
- Hearing loss
- Swollen face
- Hoarse voice
- Muscle and joint aches
- Menstrual irregularities
- Memory loss
- Difficulty concentrating
Conditions That May Be Mistaken for Hypothyroidism
The following diseases may display signs and symptoms similar to those of hypothyroidism:
- Nephrotic syndrome
- Chronic nephritis (inflammation of the kidneys)
- Neurasthenia (unexplained fatigue, most likely due to psychiatric illness)
- Depression
- Euthyroid sick syndrome
- Congestive heart failure
- Primary amyloidosis (metabolic disorder)
- Anemia (including pernicious anemia)
- Pituitary adenoma (a rare growth on the gland)
- Dementia (mental impairment) from other causes
- Chronic kidney insufficiency
- Psychiatric abnormalities
How Hypothyroidism Is Diagnosed
If hypothyroidism is suspected, your doctor will review your medical history and perform a physical examination. A series of laboratory blood or tests will likely be performed, depending on your symptoms. Your doctor will review the test results and evaluate your signs and symptoms to achieve a diagnosis. If it's a positive one, your condition will be classified as euthyroid, subclinical hypothyroidism, or hypothyroidism, which range from mild to more severe.
Mild hypothyroidism, known as euthyroid, may be difficult to diagnose, since the amount of thyroid hormone needed is different for each person.
Physical examination
During your examination, it's important to let your doctor know about your medical history or any unusual injuries. This may help guide him or her to make the correct diagnosis. Thyroid disease may run in families or be associated with other autoimmune diseases. If you've ever been treated for hyperthyroidism, this too could be a cause of thyroid hormone deficiency. Old neck injuries or trauma may also have caused damage to the delicate thyroid gland, causing primary hypothyroidism. And rarely, an inadequate intake of dietary iodine can cause primary hypothyroidism. Look for the presence of goiter, a swelling in the front of the neck.
Laboratory tests
Many different tests are used to help diagnose hypothyroidism. Most are blood tests designed to measure various hormones and/or your thyroid gland's iodine uptake. Test results for the following substances would suggest hypothyroidism:
- Thyroid-stimulating hormone (TSH) in blood (elevated in primary, lowered in secondary)
- Total or free thyroxine (T-4), a thyroid hormone, in blood (decreased)
- Total or free triiodinethyronine (T-3), another form of thyroid hormone, in blood (may be decreased)
- Iodine uptake by thyroid gland using radioactive iodine (low in primary hypothyroidism)
- Blood cholesterol, liver enzymes, and creatine kinase (increased)
- Antibodies against thyroperoxidase and thyroglobulin (present in Hashimoto's thyroiditis)
Goals of Treatment
For many people, hypoglycemia and its symptoms can be treated effectively through diet and medication. Depending upon it severity, hypoglycemia can be either relatively easy or difficult to manage. Learning more about this condition and how to treat it can be very helpful in its management.
If the hypoglycemia is caused by excess insulin or antidiabetic medication, reducing the dosages may cure the problem. If it is caused by an insulin-secreting tumor, the condition can be cured through surgery.
Specific treatment goals include stabilizing blood-sugar levels when they are in crisis and learning as much as possible about the condition so that hypoglycemic episodes can be avoided. Training family members so that they can help in the event of a hypoglycemic episode is also good.
Treatment Overview
The treatment of hypoglycemia varies, depending on its cause. Most often, treatment involves changes in diet, accompanied by medication, which help manage the condition and stave off hypoglycemic episodes. For people with diabetes who have frequent hyperglycemic episodes, more attention to insulin dosing and blood-sugar management may be needed.
Drug therapy
The use of drugs varies with the underlying cause of hypoglycemia.
- When there are mild symptoms in an alert person, sugar (either glucose or dextrose) in tablet form is available, but fruit juice, milk, soda, or candy may serve the purpose.
- If someone with hypoglycemia is unable to take sugar orally, glucagon injected under the skin or into muscle, as well as intravenous glucose, may be used.
- In the case of hormone deficiencies, hormone replacement may be used.
- When insulin-secreting tumors cannot be removed surgically, Proglycem (diazoxide) and Sandostatin (octreotide) have been used.
Surgery
If your hypoglycemia is caused by an insulinoma (an insulin-secreting tumor), surgery is an option. About 90% of these tumors are benign; however, they can be difficult to diagnose because they usually stimulate the pancreas to produce excess insulin intermittently.
Appropriate Healthcare Setting
Treatment involving blood tests and then diet and medication modifications is usually done on an outpatient basis. Inpatient treatment may be necessary during severe hyperglycemic episodes or if surgery is needed to correct the problem.
Healthcare Professionals Who May Be Involved in Treatment
The following healthcare providers may be involved in the care of hypoglycemia:
- Internists
- Pediatricians
- Family medicine physicians
- Endocrinologists
- General surgeons
Activity & Diet Recommendations
Activity
Be attentive to your exercise routine. Plan around your glucose cycles. If you have fasting hypoglycemia, don't exercise for five hours after a meal-- you're more likely to dip into a hypoglycemic state. If you have reactive hypoglycemia, avoid exercising two to four hours after a meal.
Exercise with a partner. Glucose levels can drop dramatically and swiftly during exercise. You can slide into the classic glucose-starved stupor and not be able to help yourself. Having others around you aware of your condition can be helpful. Carry fast-acting carbohydrates with you when you exercise.
Hypoglycemia caused by medication is difficult to handle with the sort of calorie and glucose burns that come with exercise. Check with your doctor for guidelines and a schedule that fits your particular case. Remember not to exercise a part of your body that you recently injected with insulin.
Diet
Eating right to help regulate blood sugar levels takes planning. The diet of choice is high in fiber, protein, and complex carbohydrates and low in sugar. Avoid skipping meals and carry a snack in case symptoms appear.
If hypoglycemia is a problem for you, consider the following diet notes:
- Fiber: Fiber is the indigestible residues of fruits and vegetables. Fiber from wheat, legumes, oat bran, nuts, seeds, psyllium-seed husks, pears, apples, and most vegetables actually sustains steady blood-sugar elevations. Eat about 50 grams of fiber a day. You can get it by choosing the most natural form of a food possible, for example, an apple instead of apple juice.
- Protein: Diets high in protein can stabilize blood sugar levels. By providing calories with a low-glycemic index, protein tends to produce much less of an insulin response than do carbohydrates. For instance, nuts (high in protein) have a glycemic index of 13, whereas corn flakes have an index of 80. Compare that to pure glucose, whose glycemic index is 100.
- Chromium: The use of chromium has been suggested by some for keeping blood glucose levels more steady and reducing hypoglycemic symptoms.
- Alcohol: The use of alcohol should be curtailed.
Quality of Life
Hypoglycemia can be a challenge to manage. Since you need to consider it whenever you eat, living with this condition requires vigilance and dietary awareness.
Considerations for Women
Some suspect that hypoglycemia may sometimes be linked to premenstrual syndrome (PMS). Experiment with this to see if you can correct your PMS with diet and attention to exercise.
Considerations for Children and Adolescents
If your child has diabetes, make sure he or she wears a Medic-Alert bracelet in case a hypoglycemic episode occurs when you can't be there.
Considerations for Older People
The brain is the first organ affected by low glucose levels, which can cause confusion, distraction, and disorientation. Because these symptoms can be mistaken for aging, emotional or mental diseases, be sure to have elders tested for hypoglycemia if they are present. Caretakers should be notified if an older person is prone to hypoglycemia.
Though hypothyroidism is a condition that demands medical attention, there are a few alternative measures you can take on your own:
Diet
- Avoid goitrogens -- foods that block iodine utilization by the thyroid. Goitrogens are in such foods as turnips, cabbage, mustard, cassava root, soybeans, peanuts, pine nuts, and millet. It is thought that cooking neutralizes the goitrogens, but you may want to avoid these foods entirely and experiment with how this makes you feel.
- Be sure to eat plenty of fruits, vegetables, and grains.
Supplements
- Iodine: The recommended dietary allowance for iodine is 150 micrograms (mcg) and can usually be met on a typical diet. Make sure you are not taking too much iodine (more than 600 mcg daily), since an abundance of iodine can also block thyroid production.
- Zinc: Zinc plays a key role in the synthesis of thyroid hormones. Naturopaths -- physicians who generally avoid drugs in favor of nondrug treatments -- recommend supplementing with zinc picolinate (30 mg/day).
- The following vitamins are all important for healthy thyroid function:
- Vitamin A
- Vitamin B-2
- Vitamin B-3
- Vitamin B-6
- Vitamin C
- Vitamin E
Exercise
Give your thyroid a jump-start by exercising; it may start to work better on its own.
Preventing Hypoglycemia
Regulating blood sugar levels takes planning. The diet of choice is high in fiber, low-fat protein, and complex carbohydrates, and low in fats and sugar. The following self-help measures can help reduce the chances or severity of hypoglycemia.
- Educate those around you. Make sure your family, friends, and co-workers are aware of your hypoglycemia condition. If they can alert you to initial symptoms, you can correct your glucose levels swiftly before they get any worse.
- Eat a high-fiber diet. Fiber is the indigestible residue of fruits and vegetables. Fibers from wheat, legumes, oat bran, nuts, seeds, psyllium-seed husks, pears, apples, and most vegetables actually sustain steady blood-sugar elevations. Eat about 50 grams of fiber a day. You can get it by choosing the most natural form of a food possible. For example, instead of choosing apple juice, eat an apple.
- Eat low-fat proteins. Diets high in low-fat protein can stabilize blood sugar levels. By providing calories with a low-glycemic index, protein tends to produce much less of an insulin response than do carbohydrates. For instance, nuts (high in protein) have a glycemic index of 13, whereas corn flakes have an index of 80. These are both in relationship to glucose, whose glycemic index is 100. Limit your consumption of meat and dairy foods in favor of low-fat protein sources like beans, tofu, nuts, and whole grains.
- Avoid alcohol. The use of alcohol should be curtailed.
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
National Institutes of Health
Institute of Diabetes, Digestive, and Kidney Disorders
9000 Rockville Pike
Bethesda, MD 20892
Phone: 301-496-3583
NDDK 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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