HEALTH: Thyroid Disease may be the Reason you feel so Bad

Researchers estimate that thyroid disease affects as many as 10% of adults in the United States. Yet millions of Americans remain undiagnosed.

What are the symptoms to keep an eye out for? The red flags of thyroid disease are unexplained weight gain or

weight loss, depression or anxiety, palpitations, and sweating.

However, these symptoms aren't specific to thyroid disorders, so a blood test is necessary to make a diagnosis.

Another sign of a thyroid problem is a lump in the neck that you can feel, which may indicate that you have developed a nodule, or small growth, on your thyroid. This diagnosis is confirmed by an ultrasound exam and may involve taking a biopsy.

To understand thyroid disease, it helps to understand what the thyroid is and which functions it is responsible for.

The thyroid is a crucial gland that sits in the neck, on the voice box. People often compare its shape to a butterfly or the letter H, with two side lobes connected by a crossbar. The gland releases thyroid hormones that are needed by cells throughout the body, affecting organs as disparate as the heart, brain, kidneys, and skin.

In turn, the thyroid is controlled by the pituitary gland, behind the nose, which sends signals telling the thyroid how much hormone to release. So we can measure thyroid function in part by measuring the hormone TSH (thyroid stimulating hormone), which the pituitary gland uses to regulate the thyroid.

There are two main types of thyroid disease. The first type consists of problems with thyroid function, most commonly hypothyroid disorder, also known as thyroid failure.

When you don't have enough thyroid hormone, you tend to gain weight and feel depressed. You can even lose consciousness, but usually we catch it long before that.

What causes the thyroid to produce insufficient thyroid hormone? Most of the time, hypothyroidism is the result of an autoimmune disease, in which the body's immune system has begun to attack itself.

The opposite problem is becoming hyperthyroid, in which the gland produces too much thyroid hormone. People with this condition tend to be anxious and inexplicably lose weight. Graves' disease is one kind of hyperthyroid disorder.

The second main type of thyroid disease — nodules — are small lumps, either solid or fluid-filled, that form inside the thyroid. Usually, the nodules are detected when the patient or doctor feels a lump in the neck, or an imaging result suggests something suspicious.

About 60% of people aged 60 or older have formed some thyroid nodules. The vast majority of these nodules are benign, but about 5% might be cancerous. So for doctors, the question becomes, how do we distinguish the problematic 5% from the benign 95%? Because larger nodules tend to be more problematic, we recommend biopsies for nodules above a certain size.

While everyone is at some risk of developing thyroid disease, some groups carry a higher risk than others. Thyroid disorders are more common in women than in men. Family history is also an indicator of risk, because these diseases tend to run in families.

What does all of this mean in terms of screening? I recommend that anyone who has symptoms should be screened. Also, any woman who may get pregnant should be screened, since a "transient," or temporary, form of thyroid disease can strike women while they are pregnant or during the first year after giving birth.

Untreated thyroid disorders can lead to complications during the pregnancy or afterward.

If you are diagnosed with a thyroid disease, the good news is that we have effective treatments. People with thyroid hormone deficiency can replace those hormones by taking a tablet every day.

Patients with overactive thyroids can take medications to control their hormone levels. If that doesn't work, we can take out the malfunctioning thyroid gland by surgery, or destroy it using radioactive iodine.

Many nodules don't need to be treated. The first step in finding out is taking a biopsy. If the results are suspicious, the next step may be to remove the nodule. Some patients will choose to have even a benign nodule removed if there is a concern that it is growing. Thyroid nodule removal surgeries have excellent success rates, as long as you go to a surgeon who does a high volume of thyroid operations.

For more information on how you can protect your thyroid health, check the web sites of the American Thyroid Association (thyroid.org) and the American Association of Clinical Endocrinologists (aace.com).

One of the best things you can do is have a regular relationship with a primary care physician. And when you go in for your next appointment, why not ask him or her to do a thyroid screening and check your gland?

Terry F. Davies, MD, FRCP, Baumritter Professor of Medicine (Endocrinology, Diabetes and Bone Diseases), Icahn School of Medicine at Mount Sinai, Co-Director, The Thyroid Center at Mount Sinai Union Square.