Hypothyroidism explained: Suppose you go in for a routine checkup and your doctor decides to test your thyroid function. You’ve experienced no thyroid disease symptoms, yet the TSH level in your blood is above the normal range. But your T4 level is normal. The results mean that you have mild, or “subclinical,” hypothyroidism, a condition that does not meet the diagnostic criteria for overt hypothyroidism but has sparked disagreement among physicians about whether to treat such patients with medication.
The importance of this question cannot be overestimated because of the large number of people who are diagnosed with subclinical thyroid disease. Studies estimate that as many as 20 percent of all women over sixty and between 4 percent to 8.5 percent of the general population have subclinical hypothyroidism.
The treatment guidelines for subclinical disease that have been developed for primary care doctors have been inconsistent over the years, and confusion within the medical community has led to debates over routine screening. One of the arguments against routine screening versus testing only people with symptoms or risk factors is that screening uncovers many mild cases that may not require or necessarily benefit from treatment.
Some cases of subclinical hypothyroidism may never progress to overt disease. Only 2.6 percent of all people with mild disease who do not test positive for anti-TPO antibodies, which suggests an underlying autoimmune disease, progress to overt disease each year. The risk of progression is higher for those with mild disease who do have anti-TPO antibodies. Among that group, 4.6 percent of people with mild disease progress to overt disease each year.
Overtreatment—for example, treating someone with subclinical disease who may not need treatment at all or giving excessive amounts to someone who would benefit from less—comes with its own risks. In some cases, a person could develop thyrotoxicosis, which means “toxic thyroid,” or too much thyroid hormone.
Long-term complications that result from overtreatment can include cardiac problems and bone loss. Most doctors agree that people with subclinical hypothyroidism who exhibit symptoms may benefit from thyroid hormone replacement, but even this hasn’t been proven. However, patients with no symptoms present a quandary. Some research over the years has shown that treatment of mild disease is needed to protect patients from the possible consequences of untreated mild disease, including high cholesterol, heart disease, and psychiatric problems along with the risk of progression to overt hypothyroidism.
In 2000, researchers in Rotterdam, The Netherlands, published a large groundbreaking population study of 1,149 women aged fifty-five and older. The researchers recommended treatment for this population after finding that women who had aortic atherosclerosis and a history of heart attacks were more likely to have subclinical hypothyroidism than those who did not. The prevalence of heart disease was highest among women who tested positive for both subclinical disease and the presence of anti-TPO antibodies. The same study reported that subclinical hypothyroidism is as great a risk factor for heart disease as other well established risk factors, including high cholesterol, smoking, hypertension, and diabetes.
Interesting Questions about Thyroid:
As with any disease, it is important that you watch for the early warning signs of thyroiditis. However, only your doctor can tell for sure whether or not you have the disease. Your doctor may examine:
- your history and physical appearance
- the amount of thyroid hormones, thyroid stimulating hormone (TSH), and antithyroid antibodies in your blood
- your sedimentation rate, a blood test useful in diagnosing painful subacute thyroiditis
- the amount of radioactive iodine taken up by your thyroid gland.
Are all thyroid lumps cancerous? How common is thyroid cancer?
Thyroid lumps (also called nodules) are growths in or on the thyroid gland. They occur in 4%-7% of the population. A thyroid nodule might cause your voice to become hoarse, or it could make breathing or swallowing difficult. However, it usually produces no symptoms and is discovered incidentally by you or your physician
More than 90% of these lumps are benign (not cancerous) and do not need to be removed. Thyroid cancer is found in only about 15,000 people each year and causes about 1,210 deaths per year. The most common form (papillary cancer) moves very slowly, and treatment is almost always successful when the cancer is detected early. A less common form (follicular cancer) also moves relatively slowly. Two less frequent forms of thyroid cancer (undifferentiated, or anaplastic, and medullary) are more serious.
Who can get thyroid cancer?
Anyone can get thyroid cancer. However, one group in particular has a higher risk: people who have had radiation to the head or neck. From the 1920s to the 1960s, x-ray treatments were used for an enlarged thymus gland, inflamed tonsils and adenoids, ringworm, acne, and many other conditions.
At that time, doctors thought the x-rays were safe. About 1 million Americans received the treatment, and some of these people will get thyroid cancer up to 40 or more years after receiving the treatment. We now know that radiation therapy to the head or neck increases the chance of developing thyroid cancer later in life. (Radioactive iodine treatments and x-rays used for testing do not increase the risk of cancer.)
Others at higher risk include a child or elderly person with a lump (nodule) in the thyroid. If a man has a thyroid nodule, it is more likely to be cancerous than if a woman has one.
Why are women more likely to get thyroid disease?
Women are also more vulnerable to autoimmune diseases. Two of the most common thyroid diseases, Hashimoto’s thyroiditis and Graves’ disease, are caused by problems with the body’s immune system. Normally, the immune system defends the body against germs and viruses. In autoimmune diseases, the system attacks the body’s own tissues. Diseases of the immune system tend to run in families.
What about thyroid disease and pregnancy?
Hyperthyroidism or hypothyroidism can affect a woman’s ability to become pregnant. They may also cause a miscarriage if they are not quickly recognized and properly treated.
Women who become pregnant may not notice signs of thyroid disease because similar symptoms can occur in a normal pregnancy. For example, patients may feel warm, tired, nervous, or shaky. In addition, enlargement of the thyroid (goiter) commonly occurs during pregnancy.
A pregnant woman is treated differently than is a non-pregnant woman or a man. For example, radioactive materials commonly used in diagnosing and treating many thyroid diseases are never used in pregnant women. The timing of a biopsy or surgery for a thyroid nodule and the choice of drugs for hyperthyroidism may be different in a pregnant woman. These issues require careful consultation with your doctor.
What is postpartum thyroiditis?
Postpartum thyroiditis is a temporary form of thyroiditis. It occurs in 5%-9% of women soon after giving birth (postpartum period). The effects are usually mild. However, the disease may recur with future pregnancies.
The symptoms usually last for six to nine months. First, the damaged thyroid gland may release its stored thyroid hormones into the blood, causing hyperthyroidism. During this time, you can develop a goiter, have a fast heart rate, and feel warm or anxious. Then, a few months later, you will either return to normal or become hypothyroid. Hypothyroidism occurs because the thyroid has been damaged and its hormone reserves used up. If this happens, you may feel tired, weak, or cold. The hypothyroidism usually lasts a few months until the thyroid gland completely recovers. Occasionally, the hypothyroidism may be permanent.
How do doctors test for thyroid disease during pregnancy?
As with any disease, it is important that you watch for the early warning signs of thyroid disease. However, only your doctor can tell for sure whether or not you have the disease. Your doctor may examine:
- your history and physical appearance
- the amount of thyroid hormones, thyroid stimulating hormone (TSH), and thyroid antibodies in your blood.
How is thyroid disease treated during pregnancy?
Pregnancy places some limits on the treatments which you can receive, because your doctor must also look out for the safety of your child. A common treatment for hyperthyroidism is radioactive iodine, but it must be avoided by women who are pregnant or nursing a baby. Surgery to remove a goiter or cancer may also be delayed until after the pregnancy. However, needle aspiration biopsy of a thyroid nodule may be safely done during pregnancy.
Treatments which may be used for thyroid disease during pregnancy include:
- antithyroid drugs, which block the production of thyroid hormone
- thyroid hormone pills, which provide the body with the right amount of thyroid hormone when the gland is not able to produce enough by itself.
Postpartum thyroiditis may or may not be treated during the hyperthyroid stage, depending upon its severity. If the patient later becomes hypothyroid, her doctor may prescribe thyroid hormone pills.
Have more questions? Need more answers? Check our Full Thyroid FAQ
However, in an effort to come to a consensus over what to do with subclinical disease, a large panel of endocrinologists sponsored by the ATA, the AACE, and the Endocrine Society put together its own recommendations for primary care physicians based on a review of all published research on the subject. In that report, published in the Journal of the American Medical Association(JAMA) in January 2004, the investigating panel found that research linking subclinical hypothyroidism to heart attacks and other cardiac problems was either flawed or inconclusive.
For instance, the panel found that the Rotterdam study, a population study based on surveys, did not establish a cause-and-effect relationship between subclinical and aortic atherosclerosis. In other words, other factors, such as lifestyle, socioeconomic status, and access to medical care, may explain the result. The panel also found that there is no clear-cut evidence that treatment of patients with mildly underactive thyroids improves symptoms, reduces cholesterol levels, or prevents progression to overt disease.
So who, if anyone, should be treated for mild disease? It really depends on your individual circumstances. One factor is just how mild your mild disease is. If your serum TSH level is elevated to anywhere between 4.5 and 10 mU/L and your T4 is normal, the panel “recommends against routine treatment” but suggests routine monitoring for progression to overt disease every six to twelve months. (See Table 4.1 for ranges of normal blood test results.) If your serum TSH level is higher than 10 mU/L and your T4 is normal, your disease is still mild, but your chances for progressing to overt disease are greater than those with lower serum TSH levels.
The panel considers treatment for this group “reasonable.”Pregnant women deserve special consideration, the panel found, because an underactive thyroid, even mildly so, in a mother has been linked to impaired brain development in her fetus. The consensus panel recommends treating all pregnant women with mild hypothyroidism but did not recommend routine screening of all pregnant women for thyroid disease. Instead, the panel urged the testing of all pregnant women with a family history of thyroid disease, a personal history of an autoimmune disorder, prior thyroid disease, or any signs and symptoms of thyroid disease.
The consensus panel advises against routine screening for the entire population, citing lack of evidence to support any preventative benefit. But it did recommend checking anyone who fell into a high-risk category, which would include all women over age sixty. The panel’s review was backed up by the U.S. Preventive Services Task Force, which issued its own report in January 2004. That body found the evidence “insufficient” to recommend for or against routine screening for thyroid disease in adults. Reports from these panels are hardly the final word on the subject.
Already the AACE, a cosponsor of the consensus panel, has issued a response that is at odds with the consensus panel findings. The group is sticking to its own recommendations, issued in 2002, which advise physicians to treat patients with TSH levels greater than 5 mU/L if the patient has a goiter or if thyroid antibodies are present. (The consensus panel did not recommend testing for antibodies in patients with mild disease, even though positive results indicate a higher chance that disease will progress, because the presence of antibodies changes neither the diagnosis of subclinical hypothyroidism nor the treatment recommended.) The AACE also cautions against relying solely on medical studies and ignoring clinical experience and suggests that physicians decide on whether treatment is warranted based on a comprehensive history and physical examination of the patient.
If you haven’t been evaluated for thyroid disease, keep in mind that because routine screening in the general population has not been recommended, it may be up to you to ask for a thyroid function test if you are experiencing symptoms and/or are at risk for thyroid disease.
Thyroid FAQ & Links to Related Articles
|There are four parathyroid glands that are normally having the size of a single rice grain. In some normal cases, they can be as big as the size of a pea.|
|Also called underactive thyroid, hypothyroidism is a disorder that is characterized by abnormal level of thyroid hormones in the body, which is too low.|
|The thyroid is a butterfly (pear)-shaped gland, it consists of 2 symmetrical lobes joined by a central isthmus that normally covers the 2nd & 3rd tracheal rings.|
|Congenital hypothyroidism is a thyroid gland disorder that may lead to deafness or mental retardation if left undetected.|
|Hypothyroidism can cause depression. Most people don?t realize that this feeling is depression caused by the thyroid gland not functioning as it should.|
|Papillary thyroid cancer is one of the thyroid cancer types. This type of thyroid cancer arises from the follicles in the thyroid gland.|
|The thyroid gland is located immediately below the larynx on each side of and anterior to the trachea. It is one of the largest of the endocrine glands|
|These thyroid hormones are responsible in regulating the body?s metabolism, which is how much food will be broken down into useful energy for consumption.|
|When the thyroid gland produces too much thyroid hormone, one may suffer from hyperthyroidism.|
|The thyroid stimulating hormone is produced by the pituitary gland. The thyroid stimulating hormone promotes the growth of the thyroid gland.|
|Thyroid hormones are chemical substances produced by the thyroid gland. The thyroid gland is located in the front of the neck.|
|Natural thyroid supplements are helpful as a remedy to thyroid disorders. Its natural ingredients assure one of its safeties in taking it.|
|The thyroid gland is an endocrine gland that is the primary responsible in regulating the body?s metabolism.|
|Thyroid surgery is used to treat people with thyroid problems such as thyroid cancer, thyroid nodules and hyperthyroidism.|
|Thyroid tests or thyroid function tests are done to check the thyroid function in one?s body. A doctor will be able to determine and diagnose the thyroid disorder.|
|Treatment for thyroid disorders should be done to prevent unwanted results caused by the severity of the condition. Consult a physician for more of these treatments.|
|Thyroidectomy is a surgical process wherein the whole or a part of the thyroid gland is removed. This surgical process is used to treat thyroid disorders.|
|Having an underactive thyroid is a minor problem but it seeks proper attention to avoid further health problems. Consult a physician about any thyroid problem.|
|Low thyroid, also known as hypothyroidism, is a condition where the thyroid gland is under active.|
|Following a healthy meal plan, exercise and proper medication goes hand in hand to treat hypothyroidism. Consult a physician for a more individualized plan.|
|Each thyroid cancer treatment depends on the type of thyroid cancer and the extent or stage of the thyroid cancer one is suffering from.|
|Parathyroid hormones are considered to be the most important endocrine regulator. It basically regulates the calcium and phosphorus concentration in the body.|
|Studies show that since 1925, the standard treatment for parathyroid disease is to surgically remove the parathyroid gland(s) which are overproducing parathyroid hormones.|
|Parathyroid adenoma is a small tumor of the parathyroid gland and is known to be the most common disorder of the gland.|
|Medullary thyroid cancer is one of the types of thyroid cancer. This type of thyroid cancer is more common in women than in men.|
|Most people don?t feel any symptoms. Others can just lose weight and just feel depressed for no reason at all.|
|Suppose you go in for a routine checkup and your doctor decides to test your thyroid function. You?ve experienced no thyroid disease symptoms|
|Hypothyroidism develops for over a long period of time. It?s normally from several months to even several years.|
|People who are suffering from hypothyroidism are advised to get plenty of exercise and have a balanced and healthy diet. The diet must be rich in protein and iodine.|
|Self medicating one?s thyroid disorder with hypothyroidism diet pills without proper information of the diet pill does not address the problem.|
|Hyperthyroidism is when the thyroid gland is overactive and produces too much thyroid hormones more than the body needs.|
|Hypothyroidism is one of the chronic diseases in the world. Hypothyroidism is also known as underactive thyroid; hypo means under or below normal.|
|Anaplastic thyroid cancer is a type of thyroid cancer that is rare and aggressive. It affects the thyroid gland and most especially its function.|
|Problems arise if the thyroid gland is overactive or underactive. There are three common thyroid disorders. These are hypothyroidism, hyperthyroidism and the thyroid nodules.|
|Hair loss may happen for so many reasons but it is commonly associated to thyroid problems such as hyperthyroidism and hypothyroidism.|
|Thyroid Function Tests are the different tests conducted to assess and determine the cause of an individual?s thyroid problems.|