Thyroid nodules

6 Important Causes of Thyroid Nodules

Thyroid nodules are fluid-filled or solid lumps formed in your thyroid gland. In this article, we will learn more about the thyroid gland, thyroid nodules, diagnosis, causes of these thyroid nodules, and treatment options.

1. About Thyroid Gland:

The thyroid gland is a vital hormone gland located at the front of the neck, under the voice box. It is butterfly-shaped. It is bilobed (has two lobes). The two lobes lie against and around each side of the trachea (windpipe) and are connected by a narrow tissue strip at the front.

The thyroid gland plays a major role in the growth, development, and metabolism of the human body. It helps in the body’s normal functioning by constantly releasing thyroid hormones in controlled amounts into the bloodstream. It helps maintain homeostasis in the body.

The thyroid gland produces three hormones:

  • Triiodothyronine, also known as T3
  • Tetraiodothyronine, also called thyroxine or T4
  • Calcitonin

T3 and T4 work together and regulate how our body uses energy. In simpler terms, they affect your metabolism. They also control your weight, muscle strength, body temperature, and nervous system. On the other hand, calcitonin is involved in bone and calcium metabolism. In simpler terms, it helps to regulate calcium levels in your body.

2. About Thyroid Nodules:

As mentioned earlier, thyroid nodules are fluid-filled or solid nodules/ lumps that may form within your thyroid gland. Most of these solid nodules are benign non-cancerous thyroid nodules. Only a small percentage of thyroid nodules are cancerous thyroid nodules. The benign thyroid nodules aren’t severe and don’t cause symptoms. Often these benign nodules may go unnoticed until the doctor discovers them during a routine medical exam. They may also get detected by your doctor during a scan that was done for another health concern. Sometimes, the thyroid nodules may become large enough to be visible. It may make it difficult to swallow or breathe also.

Symptoms:

Most thyroid nodules do not show any signs or symptoms. But sometimes, some nodules become so large that they can show the following signs and symptoms:

  • Such nodules may be seen from the outside, often as a swelling at the base of your neck
  • They may be felt on touching
  • They may press on the oesophagus or windpipe while swallowing or breathing respectively, making it difficult to swallow or breathe

In some cases, thyroid nodules produce additional thyroxine. Additional thyroxine release may produce hyperthyroidism symptoms (an overproduction of thyroid hormones). These symptoms include:

  • Unexplained rapid weight loss
  • Increases sweating
  • Nervousness
  • Tremors
  • Irregular or rapid heartbeat
Thyroid Nodules
By mikesaran/ Unlim Photos

3. Diagnosis:

While assessing a lump or nodule in your neck, one of your doctor’s main goals is to rule out the possibility of cancer. Another important goal is to check for the proper functioning of the thyroid gland. For all the goals, different tests are performed on the patient and the results are analyzed for correct diagnosis.

Physical Exam:

This is the simplest examination in which the patient is asked to swallow while the doctor examines the thyroid gland. If a nodule is present in your thyroid gland, it will usually move up and down during swallowing. The doctor also analyzes and looks for the physical signs and symptoms of hyperthyroidism like tremors, overly active reflexes, and a rapid or irregular heartbeat. The doctor may also look out for signs and symptoms of hypothyroidism like a slow heartbeat, dry skin and facial swelling.

Thyroid Gland Function Test:

Tests that measure blood levels of thyroid-stimulating hormone (TSH) and hormones produced by your thyroid gland are done. It can indicate whether you have hyperthyroidism or hypothyroidism. Treatment will accordingly vary.

Ultrasound:

This imaging technique involves high-frequency sound waves to produce images of your thyroid gland. It provides the most accurate information in the form of an image about the shape and structure of nodules. Through thyroid ultrasound, doctors can distinguish cysts from solid nodules or determine if multiple nodules are present. Doctors may also use the data from ultrasound as a guide in performing a fine-needle aspiration biopsy.

Fine-Needle Aspiration Biopsy:

To make sure there is no cancer present, doctors perform a biopsy. In this, a small sample portion of cells is removed via a very thin needle insertion. It doesn’t take a lot of time. However, there are risk factors involved in this. The doctor uses ultrasound to help guide the placement of the needle. After extraction, these small sample portions of cells are sent to a laboratory to analyze them under a microscope.

Thyroid Scan:

Another method to evaluate thyroid nodules is a thyroid scan. In this test, an isotope of radioactive iodine is injected into a vein in the arm. A special camera produces an image of the thyroid on a computer screen while the patient is lying down. The nodules that produce excess thyroid hormone (hot nodules) are illuminated on the screen during the scan because they take up more of the isotope than normal thyroid tissue does. Hot nodules are mostly non-cancerous. Sometimes, nodules that take up less of the isotope (cold nodules) are generally cancerous. However, a thyroid scan can’t distinguish between cancerous and non-cancerous nodules.

Thyroid Nodules

By kuprevich/ Unlim Photos

4. Causes of Thyroid Nodules:

There are several causes of thyroid nodules:

a) Overgrowth of normal thyroid tissue: The term thyroid adenoma is used for a condition where an overgrowth of normal thyroid tissue occurs due to unclear reasons. It is non-cancerous and is not considered serious unless it causes obstruction or any bothersome symptoms due to its size.

b) Chronic inflammation of the thyroid: Chronic inflammation of the thyroid can be because of Hashimoto’s disease. Hashimoto’s disease is an autoimmune disorder that causes inflammation. This leads to an enlarged thyroid gland and nodules. This often results in hypothyroidism.

c) Iodine deficiency: Adults need about a total of 140 micrograms of iodine in their diet per day. Lack of iodine in daily diet can cause its deficiency in the body. Iodine deficiency can cause thyroid nodules. Eating a balanced diet which has a proper proportion of iodine can prevent or even cure iodine deficiency. Foods rich in iodine are seaweed, fish, dairy and many more.

d) Thyroid cysts: Thyroid cysts are generally non-cancerous, but they occasionally may contain cancerous solid parts. In general, thyroid cysts are fluid-filled cavities in the thyroid. They most commonly result from degenerating thyroid adenomas. However, often solid components are mixed with fluid in thyroid cysts.

e) Multinodular goiter: The term goiter is used to describe any enlargement of the thyroid gland because of iodine deficiency or a thyroid disorder. A multinodular goiter contains many different nodules within the goiter. However, its cause is less clear.

f) Thyroid cancer: The chances of nodules being cancerous are very thin but painful and large nodules which cause discomfort are a matter of worry. Such cases require professional help from an oncologist.

5. Complications:

Complications in some cases of thyroid nodules include:

  • Hyperthyroidism:

    Nodules or goiter can produce excessive thyroid hormone, leading to many problems. Such a condition of excessive thyroid hormone release in the body is called hyperthyroidism. Hyperthyroidism can lead to weight loss, muscle weakness, heat intolerance, and anxiousness or irritability. Hyperthyroidism causes complications like a chronic irregular heartbeat (arrhythmia), fragile bones, and thyrotoxic crisis (a rare but possible condition where signs and symptoms intensify, leading to an immediate need for medical care).

  • Problems while swallowing or breathing:

    Multinodular goiter or large nodules can interfere with swallowing or breathing and may cause immense discomfort.

  • Problems caused due to thyroid nodule surgeries:

    If your doctor suggests surgery to remove a nodule or a bunch of nodules, you may require thyroid hormone replacement therapy for the rest of your life.

6. Treatment:

Treatment depends on the type of thyroid nodules.

I) Treating Benign Nodules:

If thyroid nodules are benign (non-cancerous thyroid nodules), treatment includes:

  • Watching the condition:

    If the biopsy results show that the patient has a non-cancerous thyroid nodule, the doctor may suggest simply watching the condition. This signifies getting a physical exam and thyroid function tests done at regular intervals. It may also include an ultrasound. Another biopsy is done in case the nodule grows larger. If a benign thyroid nodule remains unchanged, you may never need treatment.

  • Thyroid hormone therapy:

    If it is revealed in the thyroid function test that your gland is not producing enough thyroid hormone, then the doctor may recommend thyroid hormone therapy.

  • Surgery:

    A benign nodule (non-cancerous nodule) may sometimes require surgery if it’s large and makes it hard to breathe or swallow. Patients with multinodular goiter may also require surgery as per the doctors, especially when the goiter constricts airways, the esophagus, or blood vessels. Nodules of an intermediate size or under any suspicion are also removed via surgy and examined for signs of cancer.

II) Treating Nodules That Cause Hyperthyroidism:

If the thyroid produces thyroid hormone in amounts exceeding the normal thyroid hormone range, then the doctor may suggest treating the hyperthyroidism. Treatments include:

Radioactive iodine:

Doctors prescribe radioactive iodine to treat hyperthyroidism. Radioactive iodine is taken in a capsule or liquid form. Your thyroid gland absorbs this radioactive iodine. After absorption, it causes the nodules to shrink, and signs and symptoms of hyperthyroidism ease within two to three months.

Anti-thyroid medications:

Doctors may prescribe anti-thyroid medication such as methimazole (Tapazole) to reduce symptoms of hyperthyroidism. It is a long-term treatment. The treatment can have some serious side effects on the patient’s liver. Hence, discussing the treatment’s risks and benefits with the doctor before taking the medications is important.

Surgery:

Surgery is the last option left when neither of the above two treatment methods works. The doctors surgically remove the overactive thyroid nodule.

III) Treating Cancerous Nodules:

Cancerous thyroid nodules are treated differently than benign nodules. In most cases, cancerous thyroid nodules require surgery.

Observation:

Very small-sized cancerous cells in the thyroid gland have a very low risk of growing. Hence, the doctor may closely watch cancerous nodules before treating them for some time. Observation includes ultrasound monitoring and performing blood tests.

Surgery:

A common treatment for cancerous nodules is surgical removal. In the past, doctors used to remove most of the thyroid tissue via a near-total thyroidectomy procedure. However, today a limited part of the thyroid gland, say half of the thyroid gland, may only be removed for some cancerous cells.

Near-total thyroidectomy may be used depending on the extent of the disease or stage. Risks include damage to the nerve that controls the vocal cords and parathyroid glands. After thyroid surgery, you’ll need lifelong treatment with levothyroxine to supply your body with thyroid hormone. The doctor will help determine the correct amount per the patient’s body to take because it may require more than hormone replacement to manage the cancer risk.

Alcohol ablation:

Alcohol ablation is another line of treatment for small cancerous nodules. This technique injects a small amount of alcohol into the cancerous thyroid nodule to destroy it. Multiple treatment sessions are often required.