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Guide to Thyroid Disease
|What Are Thyroid Nodules?
Thyroid nodules refer to any abnormal little bumps which sometimes grow on the thyroid gland (see more pictures). The thyroid is nearly always growing nodules and most are so small they are never discovered or if they are discovered, they turn out to be of little concern. In fact if they did not grow in such a prominent place (the neck), most of the time they would be missed. As it is, any that are discovered usually need to be examined in case they are cancerous. Fortunately only 5 percent turn out to be malignant, and even then the patient is nearly always cured. It is estimated that up to 20 percent of Americans may have nodules but most remain harmlessly undiagnosed. Typically people first notice a small bump on their throat during a routine medical exam or when they look at their neck in the mirror.
What Are The Symptoms?
Most nodules do not produce symptoms. They are usually only uncovered during a routine physical examination or as previously mentioned, you might notice a lump when you look in the mirror. You can have one or many nodules. Generally speaking, the more nodules you have, the less likely it is to be cancer. If the nodules contain specific thyroid cells, they can start to produce thyroid hormones. In such cases the patient may complain of symptoms of thyroid disease, specifically hyperthyroidism (the over production of thyroid hormones). Occasionally patients complain of:
• Ear, neck or jaw pain.
• Difficulties swallowing.
• Tickling in the throat.
• Shortness of breath if the nodule presses down on the windpipe.
• Hoarseness (rarely).
• If the thyroid gland also becomes swollen, the neck can become enlarged, this is known as a goiter (picture). Goiters are usually quite harmless and painless but can be cosmetically unsightly.
What Are The Causes?
We still do not know what causes thyroid nodules. Possible causes include:
1. Gender: Nodules are much more common in women so some scientists think they may have something to do with hormone changes - women’s hormones change considerably during their menstrual cycle, pregnancy and menopause.
2. After Surgery: People who have part of their thyroid gland surgically removed as a treatment for thyroid disease or cancer are more prone. Sometimes part of the tissue can grow back, and this tissue may be prone to developing nodules.
3. Hashimoto’s Disease: Also called chronic thyroiditis, this condition may cause inflammation and swelling of the thyroid gland, making it more prone to developing nodules.
4. Virus: A temporary virus can cause inflammation of the thyroid gland (known as subacute thyroiditis). This may make it prone to nodules.
5. Iodine: Lack of iodine in the diet. In the west most table salt and many other staple food products have been iodized, so this is not usually a cause in America (see causes of thyroid disease). It is the main cause however in poorer countries.
How Is It Diagnosed?
Most thyroid nodules are discovered during a routine medical examination or by the patient themselves. Once a nodule is found, your doctor will try to work out if the lump is the only problem with your thyroid, or if it is a symptom of a more general thyroid condition such as hyperthyroidism or hypothyroidism. He will feel your neck to see if the thyroid is swollen, and to check how many nodules you have. He will also put pressure on the nodule to see if it moves (fixed nodules are more likely to be thyroid cancer). Some or all of the following thyroid tests may also be performed:
Your doctor may take a blood sample and send it to a lab to check your thyroid hormones levels (TSH and maybe T4 hormones). This will establish if you have a thyroid disease. However most patients with nodules turn out to have normal thyroids.
Checking For Cancer
As 5 percent of nodules can be cancerous, your doctor may recommend further tests such as a thyroid scan, and/or an ultrasound scan or thyroid fine needle biopsy. It is not normally possible to determine if a nodule is cancerous with a physical examination and blood tests alone.
Thyroid Ultrasound Scan
This is like a pregnancy ultrasound scan, but is carried out on the neck instead of the tummy. It is used to detect nodules that may be missed by a physical examination. It can tell if the nodules are fluid filled (cysts) or solid (more likely to be malignant). It is also sometimes used in combination with a fine needle biopsy to guide the needle to the correct area. Sometimes small bits of calcium and increased blood flow to a nodule are discovered, these abnormalities can indicate cancer (but not usually). While scans are useful, they cannot conclusively determine if a nodule is cancerous or not.
Radionuclide Thyroid Scan
Next you may undergo a radioactive iodine uptake test. The patient is given a pill to swallow which contains radioactive iodine. A nuclear camera (like a Geiger counter) is passed over the thyroid to determine how the thyroid picks up the iodine. If a nodule takes up most of the iodine, and the rest of the gland is less active, it is called 'hot'. Cancerous nodules are usually 'cold' which means they don't take up the radioactivity. Even then, most cold nodules are not cancerous. If the scan shows that you have a cold nodule, the only way to determine for sure is to examine a piece of the nodule tissue underneath a microscope (biopsy).
Thyroid Fine Needle Biopsy
Sometimes doctors skip the scans and go straight to a fine needle biopsy. This involves injecting a small needle directly into the nodule and a section is suctioned out and sent to a lab for testing. If the nodule is not easily felt, an ultrasound scan may be used in combination to guide the needle. This procedure can be carried out in a doctor’s office.
Needle with ultrasound scan
Possible results are:
Benign Ademoma: 65 percent of cases: The tissue is non-cancerous and it will not turn malignant in the future.
Suspicious: 15 percent of cases, and of these 20 percent turn out to be cancer: These are probably the most difficult to deal with. The biopsy result determined that there is no obvious sign of cancer but changes have taken place in the cells which sometimes happen with cancer. Doctors may need to remove the whole nodule by surgery to examine it. However this can be avoided if you undergo the radionuclide scan and the nodule turns out to be hot.
Cancer: About 5 percent of all biopsies turn out to be cancer.
Non-Diagnostic: In 10 percent of cases it is not possible to make a diagnosis, usually because a larger tissue sample is needed. The nodule will need to be surgically removed for analysis.
How Is It Treated?
Treating Nodules That Are Not Cancer
Nodules that are discovered to be 'hot' during a radionuclide scan need to be treated because they tend to produce hyperthyroidism. One choice is to take radioiodine, a radioactive iodine drink which destroys part of the thyroid gland. This is also one of the treatment options for patients with Graves disease. One of the downsides is that 40 percent of people who take radioactive iodine go on to develop hypothyroidism in later life. The remainder however return to normal thyroid function. Another option is to have the nodule surgically removed, but even then about 50 percent become hypothyroid later. A newer therapy involves injecting the nodule directly with ethanol several times over a few days. This can destroy the nodule - but the big advantage is there is no risk of developing hypothyroidism. In other instances, if you have nodules that are 'warm', 'cold' or fluid-filled (cysts), your doctor may just recommend a wait-and-see approach. Occasionally patients are offered thyroid hormone treatment to shrink the nodule (this is known as suppression therapy). You should have an ultrasound scan done every year to check that the nodule has not grown. If it has, you will need another biopsy and may need surgery to remove to it.
Treating Nodules That Are Cancerous
Malignant nodules (and sometimes benign nodules that have grown very large) are usually removed by thyroid surgery. This procedure is expensive and tricky to carry out, so it is important that you are operated on by a qualified thyroid surgeon (and not a general surgeon). On deciding how much of your thyroid gland to remove (part or all), your surgeon will rely on the advice of a pathologist. The pathologist may also recommend removing nearby lymph nodes to check if the cancer has spread. As it is such a skilled area, do not rely solely on the referral of your doctor. For a list of thyroid surgeons in the US by State, go to www.edocrinesurgery.org.
I had a Fine Needle Aspiration on my thyroid. The doctors said I had a 4cm sized nodule on my thyroid and it would need a biopsy. I was really scared. The only part of the procedure that ended up hurting was when they numb the thyroid before performing the actual biopsy. It felt like a bee sting. After that, I felt nothing. It's relatively quick and all that's left on my neck is a tiny hole. I waited a week for my results and then the nurse phoned to say they needed to do it again because they didn't get enough of a sample. Apparently this is quite common. I went back in again, and then the doctor announced there is nothing to biopsy. That I hadn't any nodules and that what they saw on the initial scan was inflammation. Since I'm taking Synthroid, this has since gone back down again. I was relieved. Now I'd always advice other people in the same situation to question the person doing a scan, and ask them if it really is a nodule or could it be inflammation.
I was diagnosed with 3 small thyroid nodules last year. I had them biopsied and they turned out to be non cancerous fortunately. I was offered surgery but chose to increase my dose of Synthroid which I'm taking for hypothyroidism instead. The nodules have since shrunk and have virtually disappeared.
I went to the doctor because I thought I was suffering from allergies. I was shocked to find out that my thyroid was enlarged. But then my symptoms suddenly made sense. I had a thyroid ultrasound scan which showed I had nodules and then underwent a radioactive iodine scan. I went to an endocrinologist for the tests and she was great. She started me on 112mg of Synthroid and within 4 weeks my thyroid has reduced again. I take the pill every day and my symptoms have disappeared.