Things That Can Go Wrong
When it's healthy, the thyroid gland quietly performs its tasks like an unsung hero, a quiet but instrumental cog in the marvelous machine known as the human body. But when it gets diseased, the problems can become annoying at best, and life-threatening at worst.
Thyroid disease is actually several medical conditions, each with its own set of signs and symptoms. The following is an overview of these different conditions.
Inexplicable weight gain. Fatigue. Memory loss. In people whose thyroid gland doesn't produce enough thyroid hormone, the result is a slowing down of all bodily functions, causing a condition called hypothyroidism.
Hypothyroidism is the most common form of thyroid disease. Although it can be temporary in some cases, most often it is a permanent medical condition that requires lifelong medication and vigilance. People who have it may notice that they feel sluggish, depressed, and unable to concentrate. But in its milder forms, they may notice nothing at all. Some people, like Susan, have no symptoms at all. In fact, it was family history that inspired Susan to have her thyroid checked:
When Susan told her nurse practitioner that her sister had been diagnosed with Hashimoto's, the nurse practitioner suggested she get screened, even though she had no symptoms. Sure enough, they found that Susan had it, too. She was immediately put on thyroid hormone replacement and notices she has more energy.
Many factors can cause an underactive thyroid, but the most common one is an autoimmune disease called Hashimoto's thyroiditis (or disease). In an autoimmune disease, the body's immune system mistakenly treats healthy tissue as a foreign invader, and attacks its own body cells. But hypothyroidism can also be caused by inflammation, radioactive iodine treatments for hyperthyroidism, removal of the thyroid gland — possibly as a result of cancer — certain medications, and problems with the pituitary gland.
Children who have Down's syndrome are more likely to develop hypothyroidism. The two conditions, as they appear in children, share similar features. Hypothyroidism, if severe, like Down's syndrome, can involve mental retardation and slow growth. Treating the hypothyroidism is still important, however, and can improve a child's growth and functioning.
Some women develop hypothyroidism during or after pregnancy, and some children are born with a deficiency in hormone production or thyroid tissue. In some cases, the cause of the hypothyroidism may remain a mystery.
Some cases of hypothyroidism are less clear-cut. TSH levels may be normal or near normal, but you may still be experiencing all the symptoms of hypothyroidism. Some doctors may be uncertain about whether to treat you. This condition is known as mild, or subclinical, hypothyroidism.
Doctors who consider TSH levels only in making a diagnosis may say you do not have hypothyroidism at all. But those who consider the symptoms you're experiencing as well as your TSH levels may be more inclined to say you are hypothyroid and give you thyroid hormone replacement.
In any case, people who have mild hypothyroidism may have the same symptoms as those with hypothyroidism — fatigue, weight gain, and depression. Some experts believe that treating mild hypothyroidism can prevent a patient from developing full-blown hypothyroidism.
Unexplained weight loss. Nervousness. A fast heartbeat. In people whose thyroid glands are producing too much thyroid hormone, the body speeds up, and the result is a less well-known thyroid condition called hyperthyroidism.
Hyperthyroidism afflicts about 1 percent of the U.S. population, and affects women five to ten times more often than men. People who have it are jittery, anxious, and have trouble catching their breath. They may be plagued by insomnia and notice that their eyes bulge. In milder forms, hyperthyroidism may produce no symptoms at all.
Many cases of hyperthyroidism are caused by Graves' disease, an autoimmune condition that causes enlargement of the thyroid gland. But it may also be the result of the growth of several nodules in the thyroid, a single nodule, inflammation and enlargement of the thyroid gland (called thyroiditis), or the overingestion of iodine. Some people who are taking thyroid medication for hypothyroidism may become hyperthyroid too, if they take too much medication. In some women, hyperthyroidism may develop after pregnancy.
Before the introduction of iodized salt in the 1920s, the United States was plagued with goiter, which is an enlargement of the thyroid gland. Goiters may be the result of too much or too little thyroid hormone, and they are not cancerous. Some patients with a goiter may have hypo- or hyperthyroidism. Others may have normal thyroid tests and still have a goiter.
But goiters can develop if you have either hypothyroidism or hyperthyroidism. In people with underactive thyroids, inadequate amounts of thyroid hormone cause TSH levels to go up, spurring the development of a goiter. Goiters that result from hypothyroidism in the United States are most often caused by Hashimoto's disease. Goiters may also be the result of an overactive thyroid brought on by Graves' disease, which causes the gland to swell and enlarge. Elsewhere in the world, where iodine deficiencies are more common, the goiter may be caused by inadequate intake of iodine.
The Great Lakes region, the Midwest, and the mountainous regions of the interior United States were once called the “goiter belt,” areas of the country where goiter was prevalent because of iodine deficiency. That problem was remedied with the introduction of iodized salt in the 1920s.
Goiters also occur when you have other thyroid problems. In some people, a goiter may be the result of a single nodule, or multiple nodules, a condition called multinodular goiter. You may also develop a goiter as the result of inflammation of the thyroid gland. Some women may develop a goiter during pregnancy as the result of a hormone called human chorionic gonadotropin (HCG).
Simply put, a nodule is a lump. The vast majority of thyroid nodules are small, benign (noncancerous), and harmless. They may occur as a single nodule or as a clump.
Most thyroid nodules are stealth invaders. You may not even notice you have a nodule until your doctor feels one in your throat during a routine physical. But if the nodule gets bigger, you may see it on your throat as a lump in the lower front of your neck. Women may see it when they're applying makeup. Men may notice it while they're shaving or if their shirt collars begin to feel uncomfortably snug.
Large nodules may actually press against your windpipe or your esophagus, making it difficult for you to breathe or swallow. They may even cause hoarseness in your voice.
Even a benign nodule may sometimes warrant surgical removal. If the nodule becomes so big that it interferes with breathing and swallowing, surgery can remove the obstruction and alleviate the pressure. You may also consider removing it if the nodule becomes large and unsightly.
Although most nodules are benign, in some cases, the nodule may be cancerous. A single nodule in an otherwise healthy gland, a nodule that is hard to the touch, or one that doesn't shrink after thyroid hormone treatments are all signs that your nodule may be cancerous. Nodules accompanied by enlargement of the lymph nodes in the neck may also indicate cancer. The bottom line is this: All nodules warrant medical attention and evaluation to pin down the exact cause and type of nodule.
There are four distinct types of thyroid cancer: papillary, follicular, medullary, and anaplastic. Each form develops in different cells of the thyroid gland and is distinct from the others. Although having cancer can be frightening to anyone, most cases of thyroid cancer are readily treated with surgery. And though having thyroid cancer means you'll need regular monitoring to detect any recurrence, most patients go on to live normal, productive lives.
Vigilance is everything when it comes to thyroid cancer, which has a recurrence rate of about 30 percent. Sometimes, the cancer returns decades after the initial diagnosis. Monitor your thyroid health regularly with routine visits to the doctor, blood tests, physical exams, and imaging techniques. Make these doctor visits a top priority.
The incidence of thyroid cancer has increased in recent years. And like most other thyroid problems, the condition is more common in women than men. Your risk also goes up if you were exposed to radiation as a child or if you have a family history of thyroid cancer.
Euthyroid Sick Syndrome
You're in the hospital for heart problems when the doctor announces your thyroid is off-kilter, too. These abnormal findings in the absence of thyroid disease is what experts call euthyroid sick syndrome. People with this condition have not had thyroid problems in the past but are now experiencing abnormalities because of another medical problem.
Euthyroid sick syndrome — sometimes called sick euthyroid — can occur with many illnesses, including cardiovascular disease, pulmonary disease, and renal problems. It may also occur with gastrointestinal disease, inflammatory conditions, and sepsis. Some people have it after surgery, trauma, or burns.
In most cases, levels of T3 are low, and reverse T3 is high, a condition called low T3 syndrome. It's possible that when the body is ill, reducing the amount of T3 — and thereby slowing bodily functions — is the body's way of conserving its resources. But in other cases, other thyroid hormones may be involved. For instance, if the euthyroid sick syndrome is severe, both T3 and T4 levels drop. And among the sickest patients, TSH levels become abnormally low.
The good news is, euthyroid sick syndrome is usually a temporary problem. As patients recover from their illness, their TSH levels may rise to hypothyroid levels until thyroid hormone levels stabilize. Eventually, all thyroid hormones become normal again.
Most experts agree that euthyroid sick syndrome is not hypothyroidism in spite of the drop in hormone levels. But many doctors are now finding that treatment with T3 has benefits. For instance, those who are suffering from heart failure may experience an improvement in their heart's pumping capacity after being treated with T3, even though they technically do not have a thyroid disorder. As a result, doctors these days are increasingly inclined to treat euthyroid sick syndrome.