This need never occur with proper treatment.
The good news is that treatment is simple, and the symptoms almost always resolve with treatment. Persons generally feel much better, more alert, and "back to being their old selves."
The other major factor to consider in assessing how serious hypothyroidism is in any given individual is the presence (and, if so, severity) of associated health conditions.
How Is Hypothyroidism Diagnosed?
Diagnosis of hypothyroidism is based on a person's medical history, a physical examination, and blood tests.
If a physician suspects hypothyroidism, he or she will look particularly at the cardiovascular system, the skin, hair, eyes, reflexes, and body temperature. The physical exam also may reveal an enlarged thyroid, which is called a goiter.
In Hashimoto's thyroiditis, if a goiter is present, it will not be tender and will have a rubbery feel.
If the goiter is tender, the cause may be subacute thyroiditis, an inflammation of the thyroid that often follows an upper respiratory infection.
Blood tests check the levels of the thyroid hormones T4, T3, and TSH, among other related substances.
Abnormally low levels of T4 and T3 indicate hypothyroidism is present.
The TSH (thyroid-stimulating hormone) level is especially important in determining whether the condition is due to a problem in the thyroid gland or in the part of the brain that stimulates thyroid function.
If the TSH level in the blood is high, the abnormality is within the thyroid gland. A high TSH level suggests that the thyroid gland is not responding properly to the stimulating effect of the TSH on the thyroid gland.
If the TSH level in the blood is low, the abnormality is within the brain or pituitary gland in the brain. It suggests that the pituitary is not releasing adequate amounts of TSH to stimulate the thyroid gland, despite levels of thyroid hormone low enough that it should do so.
Among adults with hypothyroidism, roughly 95% of cases represent problems in the thyroid gland. In about 5% of cases, the abnormality is found in the brain or in the pituitary gland, almost always the pituitary gland.
If blood tests suggest that the problem is in the glands in the brain, imaging tests of the brain may be necessary. These include CT scans, which are sophisticated x-rays, and MRI scans, which use magnets to create images of the inner body.
Other blood tests include an antibody test, which is a blood test to detect antithyroid antibodies. High levels of these antibodies suggest that a person may have Hashimoto's thyroiditis.
Need To Know:
Of the blood tests for hypothyroidism, the TSH is the most sensitive test. The role of TSH is to stimulate the thyroid gland to produce thyroid hormone when the level of hormone in the body drops.
If the TSH level is above 6, then a diagnosis of hypothyroidism will be made.
However, if the thyroid hormone levels are normal and the person has no symptoms, then the conditions is said to be "subclinical." This means that the hypothyroidism has been diagnosed by a blood test only, since there are no symptoms.
Most people feel best when their TSH level is between 0.5 and 2.5.
Nice To Know:
The American Thyroid Association, a national professional organization of thyroid specialists, recommends that women over age 35 should be screened every five years for hypothyroidism.
How Is Hypothyroidism Treated?
Treatment of hypothyroidism is simple. It involves taking daily thyroid hormone replacement medication. This supplies the body with thyroid hormone to replace what isn't being produced by the thyroid gland.
The replacement thyroid hormone is artificially manufactured and is structurally identical to the thyroid hormone produced naturally in the body. It is a synthetic derivative of the thyroid hormone T4 and is called levothyroxine. Brand names include Synthroid, Levothroid, Levoxyl, Levo-T, as well as numerous generic preparations.
Synthetic thyroid hormone (T4) is made in a wide range of strengths so that dosage can be individually tailored to each person's needs.
An adult typically starts with 0.1-0.15 milligrams per day, and the dosage is adjusted over time to reach normal blood levels, reflected by normal blood levels of TSH. It is important that older adults, especially those with heart disease, start at a low dose and increase it slowly. This minimizes the risk that the increase in metabolic activity due to thyroid hormone replacement therapy will stress the heart.
Because T4 is converted into T3 (the other very important thyroid hormone) within the body, physicians are comfortable using T4 therapy alone. However, one recent study has suggested some persons may benefit from combined T3 and T4 therapy.
Need To Know:
People differ in how quickly they respond to the medication.
It is important to take the medication regularly as prescribed. Some hypothyroidism sufferers feel a marked improvement after only a couple weeks on medication. They find that their heart rate increases to normal range, they lose the weight they gained, and their skin and hair will return to normal. Some feel much improved in themselves only after a couple of weeks of treatment. It takes a little longer for the enlarged thyroid to decrease in size and for the "bad cholesterol" to return to normal levels.
But others may find they still have various symptoms at six months or longer after beginning medication. If it's taking that long, it's usually because the dose is inadequate to bring the thyroid hormone levels into the normal range. The doctor may need to increase the dose, or perhaps try a combination of drugs with T4 and T3. A person who frequently forgets to take their medication will also not benefit from improvement in their symptoms.If the symptoms persist even though the blood tests of thyroid function are normal, it is likely that the symptoms are not due to thyroid hormone deficiency.
Even cats can develop hypothyroidism
It may be useful for an individual with newly diagnosed hypothyroidism to list their most distressing symptoms and to track changes in them over time after hormone therapy is begun.
Some people find that their physician will increase the dosage of their thyroid medication every year or two, in order to keep their blood levels of thyroid hormone within the normal range. This is because the inflammation of the thyroid gland may continue affecting more thyroid hormone producing cells, thus causing the thyroid to produce even less thyroid hormone than before.
Need To Know:
It is important not to take too much thyroid hormone, since this can cause symptoms of hyperthyroidism. These symptoms include a fast heart rate, tremor (shaking), excessive sweating, inability to tolerate heat, and abnormal heart rhythms.
Nice To Know:
Individuals diagnosed with subclinical hypothyroidism - when their TSH levels are high but thyroid hormone levels are normal, and they are not feeling any symptoms - are not always treated with replacement thyroid hormone. The decision is an individual one, made by the person and the physician. But up to half of such individuals will feel better after taking thyroid medication, and others will have improved cholesterol levels in the blood.
What Other Health Problems May Be Associated With Hypothyroidism?
Several potentially significant health conditions are common in persons with hypothyroidism.
They include:
Goiter
Goiter is a general term for an enlarged thyroid gland that has the appearance of a swelling or fullness in the neck. Many persons with Hashimoto's thyroiditis have a goiter. Although the thyroid gland is usually painless, there can be some discomfort. At the extreme, large goiters can interfere with swallowing, breathing, or both. In many cases, goiters decrease in size, often considerably, after thyroid hormone replacement therapy is begun. Surgery is rarely required.
Nice To Know:
Before the connection of iodine and thyroid function was made, people realized that goiters (large thyroid gland seen as a swelling in the neck) were more common in certain areas-areas we recognize as low in iodine in the average diet. Indeed, the area around the Great Lakes was called the "Goiter Belt." The goiters in many people living there were not due to a problem within the thyroid such as Hashimoto's thyroiditis. Instead, the goiter developed because of the lack of iodine needed for the production of thyroid hormone.
The cells of the thyroid gland increased in size and number in response to long-term high levels of TSH, the hormone that stimulates the thyroid to produce thyroid hormone, working overtime in an effort to get the thyroid gland to produce adequate amounts of thyroid hormone, despite the low level of available iodine. This ability of the cells to adapt to chronically low levels of dietary iodine by enlargement and increase in function meant that many people retained low normal levels of thyroid hormone because their thyroid cells could take up and use virtually all of the iodine they consumed.
Heart Disease
One of the major organs affected by thyroid hormone is the heart. Increased heart rate and palpitations are common in persons with untreated hyperthyroidism, and a slowed heart rate is common in persons with hypothyroidism.
Need To Know:
Persons who have hypothyroidism and heart disease should discuss their cardiac symptoms with their doctors before beginning thyroid hormone treatment.
Individuals having frequent attacks of angina, the heavy pain typically felt in the chest, jaw, or left arm, have symptoms indicating that their hearts are not receiving enough blood during the periods when angina is felt.
These individuals should plan the early phase of thyroid hormone therapy so that minimal stress is placed on the heart due to increased metabolic activity. This may be done by starting at a low dose of thyroid hormone, limiting exertion, or both.
If angina or other symptoms persist or worsen even on a low dose of thyroid hormone, other treatments may be required for the heart condition.
High Cholesterol
The decreased metabolic activity associated with hypothyroidism leads to increased blood levels of cholesterol. Individuals whose blood cholesterol levels are found to be high, particularly if they do not have a previous history of high cholesterol, may be advised to have thyroid hormone levels checked. If the high cholesterol is due (at least in part) to hypothyroidism, improvement will come after hormone treatment is begun. A low-fat, low-cholesterol diet will also help; if cholesterol levels remain high, appropriate drug therapy may be needed to lower them.
Anemia
Anemia is the general term for any condition marked by a low red blood cell count. Because red blood cells carry oxygen between the lungs and the rest of the body, persons with anemia often feel tired with little exertion. This fatigue is in addition to the fatigue felt due to untreated hypothyroidism. Persons who have hypothyroidism, heart disease, and anemia become particularly tired and may develop angina or worsening of their angina.
Individuals with hypothyroidism may become anemic due to inadequate stimulation of red blood cell development in the bone marrow; this type of anemia (as well as persistent feelings of fatigue) usually goes away after thyroid hormone treatment is begun. Over-the-counter iron supplements and other preparations are not helpful.
However, if a premenopausal woman with untreated hypothyroidism has had heavy menstrual periods, she may have iron deficiency contributing to her anemic condition. These women will find iron supplementation useful in combination with their thyroid hormone treatment.
Hypothyroid persons with anemia, particularly elderly persons, should also be checked for possible pernicious anemia, an autoimmune form of anemia characterized by vitamin B12 deficiency. The same genes that cause a vulnerability to development of Hashimoto's thyroiditis can cause vulnerability to pernicious anemia, so it is particularly important to look for in anemic individuals who have a history of Hashimoto's thyroiditis.
Infertility
Infertility is common in women whose thyroid hormone levels are low, and some women are diagnosed with hypothyroidism as part of a medical exam for infertility. After thyroid hormone treatment is begun, it is usually easier to conceive.
Because thyroid hormone crosses the placenta in small amounts, the thyroid hormone taken by the expectant mother may have important effects on the developing fetus.
Because the dose of thyroid hormone may need to be increased after a woman has conceived, it is valuable to get baseline (pre-pregnancy) thyroid tests (including TSH) and to periodically recheck during the pregnancy.
After delivery, the mother's thyroid hormone needs typically return to pre-pregnancy levels.
If You Are Having Surgery
It is generally better to schedule elective surgery for one to two months after beginning thyroid hormone treatment, because thyroid hormone levels will have come toward or into the normal range. The daily dose of thyroid hormone can be continued up to the time of surgery, although skipping a dose on the morning of surgery will not lead to problems.
On the other hand, if there is a pressing need for surgery it usually can be performed safely in an untreated or partially treated person with hypothyroidism.
Hypothyroidism And Pregnancy
Hypothyroidism can develop during or after pregnancy. It also can affect a woman's ability to become pregnant.
A woman has a 25% higher risk for developing hypothyroidism after pregnancy if she has diabetes or another autoimmune disorder. A miscarriage may be an indication that antithyroid antibodies were present before pregnancy. These antibodies do not cause the miscarriage, but seem to be a marker for other immune system problems that can lead to pregnancy loss.
How Hypothyroidism Can Affect Pregnancy
Hypothyroidism can affect pregnancy in several ways:
It can cause infertility in women because it can prevent the production of eggs.
A pregnant woman with hypothyroidism is at higher risk for miscarriage.
Women with untreated hypothyroidism near the time of delivery are in danger of developing high blood pressure and premature delivery.
Babies born to women with untreated hypothyroidism may not achieve their full intellectual potential.
Untreated hypothyroidism can cause serious problems for an unborn child, so many experts recommend that all pregnant women be tested for thyroid function during the pregnancy.
Every woman treated with thyroid hormone who anticipates becoming pregnant or is found to be pregnant should have her thyroid hormone levels monitored more closely. Some woman may need to have their dosage of medication increased by as much as 50% during pregnancy. Thyroid medication is safe to take during pregnancy.
A collaboration between a woman's endocrinologist and obstetrician will maximize the chances for a successful pregnancy and delivery and make the mother's postpartum adjustments as easy as possible.
Hypothyroidism Resulting From Pregnancy
One in every 20 women will develop hypothyroidism after pregnancy. This happens because they developed antibodies to their own thyroid prior to the pregnancy, and this caused an inflammation of the thyroid after delivery. This condition most often develops between four months to a year after delivery and usually resolves on its own. If it is long lasting or permanent, it is easily treated with medication.
Nice To Know:
Q: We tried to conceive for several years, and now I'm finally pregnant. My obstetrician did some blood work when I went to see her, and she says I'm at risk for thyroid trouble after the baby comes. I don't recall any doctor talking about my thyroid before. What does she mean?
A: Postpartum thyroiditis (an inflammatory condition of the thyroid that develops after delivery) affects about 5% to 9% of mothers. About 80% to 90% of women who develop postpartum thyroiditis had antibodies directed against their thyroid gland in their blood before their pregnancies. Ask your doctor what she found in your blood test results - do you have antithyroid antibodies in your blood? A consultation with an endocrinologist may be helpful.
Living With Hypothyroidism
Hypothyroidism can be treated easily and inexpensively with daily thyroid hormone (T4). This treatment supplies the hormone missing in the body and allows organs to return to a proper level of stimulation. Symptoms that had been distressing improve or disappear after hormone therapy has been begun.
Persons with hypothyroidism should remain aware of the symptoms of both hypothyroidism and hyperthyroidism so that they can alert their doctors if symptoms appear.
Symptoms of hyperthyroidism occur when the body's need for thyroid hormone decreases, and the previously correct dose becomes excessive. Changes that the individual might notice include a feeling of nervousness, a rapid heartbeat, intolerance of hot environments, and diarrhea.
Symptoms of hypothyroidism occur when the body's need for thyroid hormone increases, and the previously correct dose becomes inadequate. Changes that the individual might notice include feelings of physical and mental fatigue, a slowed heartbeat, intolerance of cold, and constipation.
Because thyroid hormone is simply a replacement for hormone no longer produced in the body, treatment does not require an individual to change lifestyle, give up alcohol, or make other changes. However, all individuals, regardless of gender or age, who take medications in addition to their thyroid hormone, should discuss the possibility of drug interactions with their doctors.
Some medications interfere with absorption of thyroid hormone from the digestive tract into the blood; such interference can keep the blood level of thyroid hormone low enough that symptoms of hypothyroidism continue or reappear.
Two commonly used drugs that can interfere with thyroid hormone absorption are
. Cholestyramine, used for reduction of blood cholesterol
. Sucralfate, used in peptic ulcer disorders
If these drugs are required, they can be taken several hours apart from the thyroid hormone tablet. Also, iron and calcium supplements may interfere with thyroid hormone absorption. These too may be taken several hours apart from the thyroid hormone medication.
Nice To Know:
Exercise is important to maintain health, but many people with hypothyroidism lack the energy to exercise. One expert suggests splitting exercise into several short sessions.
Putting It All Together
. Here is a summary of the important facts and information related to hypothyroidism.
. Hypothyroidism is the condition marked by too little thyroid hormone in the blood.
. Symptoms of hypothyroidism include slowed heartbeat, tiredness, difficulty thinking and remembering, dry and flaky skin, constipation, and inability to tolerate the cold.
. Hypothyroidism can occur at any age, from birth well into the senior years.
. Diagnosis of often delayed or missed because symptoms are subtle and can be attributed to other causes, such as aging or stress.
. Hypothyroidism is diagnosed with a medical exam and blood testing.
. The condition can be easily and successfully treated with medication that replaces the thyroid hormone that is lacking in the body.
. Regular monitoring via blood testing provides the means for ensuring appropriate hormone replacement therapy for the rest of one's life.
. Hypothyroidism can affect a woman's ability to become pregnant and also the health of her unborn child. Pregnant women can safely take thyroid medication, as it does not affect a developing fetus adversely.
. Most of the symptoms of hypothyroidism improve greatly or disappear after thyroid hormone treatment is begun.
. Thyroid hormone treatment may be needed for life, but fortunately treatment is simple, inexpensive, and easily monitored.