Thyroid Glands

What are hot and cold nodules?

Thyroid nodules do not function like normal thyroid tissue. A thyroid image (scan) done with a radioactive chemical shows the size, shape, and function of the gland and of thyroid nodules. A nodule that takes up more of the radioactive material than the rest of the gland is called a hot nodule.

A nodule that takes up less radioactive material is a cold nodule. Hot nodules are seldom cancerous, but less than 10% of all nodules are hot. Cold nodules may or may not be cancerous. All lumps should be checked by your doctor.

How do doctors test nodules for cancer?

Your doctor can use several tests to find out whether or not a thyroid lump is cancerous.

• A thyroid image or scan shows the size, shape, and function of the gland. It uses a tiny amount of a radioactive chemical, usually iodine or technetium, which the thyroid absorbs from the blood. A special camera then creates a picture, showing how much iodine was absorbed by each part of the gland.
• In needle aspiration biopsy, a small needle is inserted into the nodule in an effort to suck out (aspirate) cells. If the nodule is a fluid-filled cyst, the aspiration often removes some or all of the fluid. If the nodule is solid, several small samples are removed for examination under the microscope. In over 90% of all cases, this testing tells the doctor whether the lump is benign or malignant.
• Ultrasound uses high-pitch sound waves to find out whether a nodule is solid or filled with fluid. About 10% of lumps are fluid-filled cysts, and they are usually not cancerous. Ultrasound may also detect other nodules that are not easily felt by the doctor. The presence of multiple nodules reduces the likelihood of cancer.

How are nodules treated?

Nodules that are thought to be benign are usually observed at regular intervals. Some patients may be advised to take thyroid hormone pills. In certain instances, the nodule may be surgically removed because of continuing growth, pressure symptoms in the neck, or for cosmetic reasons.

Fluid-filled cysts that come back after several aspirations may need to be removed.

If the testing shows a nodule that is, or might be, malignant (cancerous), your doctor will recommend surgery. (You should discuss special situations, such as pregnancy, with your doctor.) The goal of surgery is to remove as much of the cancerous tissue as possible. If the cancer is found in the early stages when it is still confined to the thyroid gland, the surgery is almost always successful. With papillary cancer, patients usually do well after treatment, even if the cancer has spread to the lymph nodes in the neck.

The surgeon starts by removing one lobe of the thyroid. This specimen is tested during surgery (frozen section) to tell the surgeon whether it is benign or malignant. If it is malignant, most or all of the thyroid is removed. If the cancer has spread, lymph nodes in the neck may also have to be removed. In addition, in patients with either papillary or follicular cancer, radioactive iodine therapy may be needed six weeks after surgery to destroy any remaining cancerous tissue.

What happens after surgery?

After surgery, patients must stay in the hospital for one to three days. They may also need to take some time off from work (one to two weeks for a desk job; three to four weeks for physical labor). Most patients do not have any trouble speaking or swallowing, and they report minimal pain after the surgery. In patients with thyroid cancer, a scan may be done approximately six weeks after surgery to detect any residual thyroid tissue that needs to be treated with radioactive iodine.

Patients with thyroid cancer will need to take thyroid hormone their entire lives. Some patients who have had a noncancerous nodule removed will also be advised to take thyroid hormone pills. These may prevent new nodules from forming in the remaining portion of the thyroid gland.

Why are women more likely to get thyroid disease?

In general, women are much more likely than men to become hyperthyroid or hypothyroid and to get Hashimoto’s thyroiditis. The reason for this is uncertain.

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.

If you or a blood relative has Hashimoto’s thyroiditis or Graves’ disease, there is a chance that your children will inherit the problem. These diseases are also linked to other autoimmune conditions, such as premature gray hair, diabetes mellitus, arthritis, and patchy loss of skin pigment (vitiligo). You should tell your child’s doctor, so that the appropriate examinations can be performed.

Also, one out of every 4,000 infants is born without a working thyroid gland. If the problem is not corrected, the child will become mentally and physically retarded. Therefore, all newborns in the United States are tested for the disease. Once the problem is discovered and corrected, the child can grow up normally.