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November 13, 2024

What are Thyroid Nodules and Their Symptoms?

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What are Thyroid Nodules and Their Symptoms?

Thyroid nodules are growths that form within the thyroid gland. While these nodules are often benign and cause no noticeable symptoms, they can sometimes lead to thyroid dysfunction or cancer. Understanding thyroid nodules’ potential causes and associated symptoms is crucial for early detection and management. This article explores what thyroid nodules are, their symptoms, how they are diagnosed, and the treatment options available.

What Are Thyroid Nodules and Their Symptoms?

What Are Thyroid Nodules?

The thyroid is a small gland at the base of the neck and a crucial part of the endocrine system. It regulates metabolism by producing hormones affecting nearly all tissues and organs, controlling energy production, temperature, heart rate, and growth. Proper thyroid function is essential for overall health, and disorders in the gland can have widespread adverse effects on the body.

Thyroid nodules are unusual growths or lumps of cells within the thyroid gland. They can develop in any location within the thyroid gland and be solid, cystic, or complex. 

  • Solid nodules contain little to no fluid. 
  • Cystic nodules are fluid-filled.
  • Complex nodules are cystic nodules that also contain a solid component.

How Common Are Thyroid Nodules?

Thyroid nodules are very common, though most people will be unaware they have one or more. It is thought that approximately 50 percent of people have at least one thyroid nodule, though they are only detected in approximately 1 to 6 percent of people. They are more common in women than men and their frequency increases with age.

Are Thyroid Nodules Cancerous?

The vast majority of thyroid nodules are not cancerous, with over 90 percent being benign and 4 to 6.5 percent of cases being cancerous. Solid nodules are more likely to be cancerous than cystic nodules, which are usually benign. Complex nodules are also usually benign; however, the solid component can become malignant, so these are typically evaluated the same way as solid nodules. 

What Causes Thyroid Nodules?

There are numerous factors that can contribute to the development of thyroid nodules, including: 

  • Overgrowth of normal thyroid tissue. 
  • Thyroid cysts. 
  • Chronic inflammation of the thyroid. 
  • Thyroid gland enlargement. 
  • Iodine deficiency. 
  • Thyroid cancer. 

Symptoms of Thyroid Nodules

In general, thyroid nodules will not cause any noticeable symptoms. However, in some cases, the following symptoms can occur: 

  • A lump in the neck
  • A hoarse voice
  • Difficulty swallowing or a sensation of needing to swallow
  • Discomfort in the neck
  • Frequent coughing and a need to keep clearing the throat
  • Pressure or discomfort on the breathing tube

In very rare cases, thyroid nodules may produce an excess of the thyroid hormone thyroxine. This can lead to symptoms associated with hyperthyroidism, including: 

  • Feelings of anxiety or nervousness
  • Heat intolerance or increased sweating
  • Rapid and irregular heart rate
  • Tremor
  • Unexplained weight loss

When to See a Doctor

While most thyroid nodules are harmless, you should see a doctor if you experience any of the symptoms listed above or if you have any reason to suspect you might have a thyroid nodule. This will allow a healthcare professional to perform a full assessment, identify or rule out any abnormalities, and test for potential hyperthyroidism and cancer. 

Diagnosing Thyroid Nodules

Thyroid nodules are typically diagnosed through a combination of physical examinations, imaging, and biopsies.

Physical Exam and Medical History

The first step in diagnosing thyroid nodules involves a medical history review and physical exam. Doctors assess your history for risk factors related to thyroid nodules, malignancy, or other thyroid conditions. During the physical exam, they will check the size, consistency, and location of the thyroid and any nodules, often asking you to swallow to observe nodule movement. The exam also includes checking for enlarged lymph nodes or signs of hypo- or hyperthyroidism, which may be followed by blood tests to measure thyroid hormone levels for further diagnosis.

Imaging Tests

The preferred imaging method for evaluating thyroid nodules is an ultrasound scan. Ultrasound scans use high-frequency sound waves directed at the tissue of interest, and the reflected sound is recorded and converted into electrical impulses. This is then processed to form an image of internal structures, in this case, the thyroid. Ultrasound imaging is advantageous for assessing thyroid nodules because it can identify small or multiple nodules and provide accurate measurements of nodule diameter for regular monitoring. 

In cases where nodules are very large, or there is a concern that they might be malignant, computed tomography (CT) or magnetic resonance imaging (MRI) scans are sometimes used as follow-up scans. These highly sensitive scans can help evaluate the impact of thyroid nodules on nearby structures and can be used in combination with contrast agents.

Fine-Needle Aspiration (FNA) Biopsy

A fine needle biopsy is commonly used to check if a thyroid nodule is cancerous. In this simple procedure, a thin needle withdraws cells from the nodule, with several samples taken from different areas to increase the chance of detecting cancer if present. A pathologist then examines the cells under a microscope to determine if the nodule is benign, malignant, or suspicious. For accuracy, this procedure is often guided by ultrasound.

Woman in a hair net looking down a microscope at a slide

Treatment Options for Thyroid Nodules

The most appropriate treatment strategy for thyroid nodules will depend on their size, type, and symptoms.

Treating Benign Nodules

  • Observation. This is the most common approach to benign nodules and involves having tests, which can include physical examinations, thyroid function tests, and imaging, at regular intervals to assess the growth and progression of the nodule. If the nodule grows, biopsies will be repeated to reassess for cancer. However, most of the time, benign nodules will never progress and never require treatment. 
  • Thyroid hormone therapy. If the assessment has indicated a case of hypothyroidism, this will be treated with thyroid hormone therapy. 
  • Surgery. In rare cases, a benign nodule may be so big that it causes difficulties or discomfort in swallowing or breathing. In these cases, surgery may be required to remove the nodule. 

Treating Nodules that Cause Hyperthyroidism

  • Radioactive iodine. Radioactive iodine is swallowed and absorbed by the thyroid gland, which causes the nodules to shrink and symptoms to subside. 
  • Anti-thyroid medications. Long-term treatment with anti-thyroid medications may also be recommended in certain cases to reduce the symptoms of hyperthyroidism. 
  • Surgery. If the above options are unsuitable, surgery to remove the nodule may be considered.

Treating Cancerous Nodules

  • Observation. Sometimes, a cancerous nodule is very small and has a low risk of growing and causing problems. Therefore, doctors often monitor very small cancerous nodules through regular imaging and blood tests before treating them. 
  • Surgery. Cancerous nodules are most often removed via surgical procedures. This usually involves removing half of the thyroid and the nodule, or in certain cases, the majority of the thyroid tissue. As a result, patients will subsequently require life-long treatment with thyroid hormones. 
  • Alcohol ablation. Small cancerous nodules can sometimes be managed by alcohol ablation. This involves injecting a small amount of alcohol into the nodule to destroy it, often over the course of several sessions.

Summary: What are Thyroid Nodules and Their Symptoms?

Thyroid nodules are relatively common and are often harmless, but they can sometimes indicate more serious health issues such as hyperthyroidism or thyroid cancer. While most nodules are benign, it's important to seek medical evaluation if any symptoms arise or if a nodule is detected. Through physical examinations, imaging, and biopsy, doctors can accurately assess the nature of thyroid nodules and determine the most appropriate treatment, whether that involves observation, medication, or surgery. Early diagnosis and treatment of thyroid nodules help to prevent complications and ensure the best possible outcomes for patients.

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