Thyroid Nodule
The thyroid gland is a small endocrine gland located at the base of the neck, just above the breastbone. Thyroid nodules are solid, sometimes fluid-filled lumps that develop within the thyroid gland.
Thyroid nodules are usually asymptomatic and are rarely malignant. They are often diagnosed at a routine medical check-up or scan. However, some thyroid nodules may become large and present with clinical symptoms such as difficulty swallowing and breathing.
Typically, thyroid nodules do not require any treatment. However, they may sometimes require radioactive iodine therapy or surgical removal of the gland.
Symptoms of Thyroid Nodule
Thyroid nodules are asymptomatic. They are diagnosed only during a routine neck exam or an imaging test for another reason, such as parathyroid disease, trauma, carotid artery disease, or cervical spine pain.
Thyroid nodules present symptoms based on the type of nodule developed. They are listed below:
Large nodules pressing against other structures in the neck can cause symptoms such as:
A visible goitre or enlarged thyroid gland
Hoarseness or change in voice
Severe pain in the neck
Difficulty in breathing, especially when lying down flat
Difficulty in swallowing food
Overactive thyroid gland produces excess thyroid hormones and likely causes symptoms such as:
Warm and sweaty skin
Increased appetite
Rapid pulse and palpitations
Restlessness and poor sleep
Nervousness or anxiety
Tremors
Skin blushing or flushing
Weight loss
Frequent bowel movements
Irregular menstrual periods
Older people with a nodule that produces excess thyroid hormone may present vague symptoms, such as:
Fatigue
Memory loss
Palpitations
Chest pain
Hashimoto's disease: When thyroid hormone is being produced in lower quantities. Symptoms include:
Dry skin
Face swelling
Fatigue
Hair loss
Constipation
Irregular menstrual periods
Feeling cold or chilly
Weight gain
Types of Thyroid Nodule
Different types of thyroid nodules that are considered benign include:
Toxic nodules that produce excessive thyroid hormones leading to hyperthyroidism.
Multinodular goitres have numerous nodules. They may also produce excessive thyroid hormone and may impinge on other structures.
Thyroid cysts are full of fluid, sometimes with other debris. They may happen after an injury.
Causes of Thyroid Nodule
Several conditions may cause nodules to develop in the thyroid gland. They are as follows:
Overgrowth of Normal Thyroid Tissue: An overgrowth of normal thyroid tissue is referred to as thyroid adenoma. It is a benign condition, and its cause is unclear. It is not considered serious unless it presents any symptoms. Some thyroid adenomas may cause hyperthyroidism.
Thyroid cyst: Fluid-filled cavities called cysts that develop in the thyroid gland and may commonly occur due to the degeneration of thyroid adenomas. Cysts are usually benign but may occasionally contain some malignant components.
Chronic inflammation of the thyroid: Hashimoto's disease is a thyroid disorder that can cause thyroid inflammation and result in enlarged nodules. This often is associated with hypothyroidism.
Multinodular goitre: A multinodular goitre contains multiple distinct nodules within the goitre.
Thyroid cancer: The chances that a nodule would turn malignant are low. However, a large and hard nodule that causes pain and discomfort may require medical attention.
Iodine deficiency: Low intake of iodine in the diet can develop thyroid nodules in the thyroid gland.
Certain other factors that increase the risk of thyroid cancer are:
○ A family history of thyroid or other endocrine cancers
○ History of radiation exposure from medical therapy or nuclear fallout.
Diagnosis of Thyroid Nodule
Diagnosing a thyroid nodule involves a physical examination and a medical history taken by the specialist. Some tests that the doctor may recommend are as follows:
Fine Needle Biopsy: A thyroid fine needle biopsy is a procedure to diagnose whether the nodule is cancerous or benign. This helps formulate the correct treatment plan. The method involves numbing the biopsy site, after which a thin gauge needle is inserted to obtain a sample for testing. The patient can return to work the same day.
Thyroid Scanning: A thyroid scan gives an image of the thyroid gland taken after a low dose of a radioactive isotope is injected or swallowed. It (radioactive isotope) is typically taken up by the thyroid cells. The scan provides information on whether the nodule is hyperfunctioning (also called hot nodule) or not. If it is not a hot nodule, the need for a fine needle biopsy is eliminated since hot nodules can rarely be malignant. However, if it is a hot nodule, it can be treated with radioiodine therapy or surgery.
Ultrasonography: In this procedure, high-frequency sound waves pass through the skin and are reflected in the machine to create detailed thyroid images. Small nodules ranging from 2-3mm can also be visualized through ultrasonography. It helps distinguish thyroid cysts from solid nodules. It can be used as a lead during fine needle biopsy to aspirate the thyroid nodules.
Blood tests may be advised to assess thyroid hormone levels.
Treatment of Thyroid Nodule
Treatment of thyroid nodules depends on their type. Some of the treatment modalities are listed here:
Watchful waiting: In benign thyroid nodules, the doctor may recommend only monitoring the symptoms. At this stage, no treatment is required.
Radioactive iodine: Radioactive iodine may be advised to treat hyperfunctioning thyroid nodules and goitres with numerous nodules. The radioactive iodine shrinks the nodules when absorbed into the thyroid gland. This treatment is contraindicated in pregnant women and women trying to conceive.
Surgery: Surgery to remove the nodules is the best treatment for cancerous nodules as they cause obstructive and suspicious symptoms. For instance, the size may be large enough to obstruct breathing or make swallowing difficult and cannot be diagnosed without being removed and examined.
Complications of Thyroid Nodule
Complications associated with some cases of thyroid nodules are:
Difficulty swallowing or breathing: Large nodules or multinodular goitre may interfere with swallowing and breathing.
Hyperthyroidism: Excessive hormones produced by the abnormal nodule or goitre may result in muscle weakness, weight loss, anxiety, irritability, and heat intolerance. Potential complications of hyperthyroidism include weak bones, irregular heartbeat, and thyrotoxic crisis.
Problems related to the surgery: Thyroid hormone replacement therapy for a lifetime is recommended in patients advised to remove the thyroid nodule.
Risk Factors of Thyroid Nodule
A person is at risk of developing thyroid nodules if any of the following conditions are true:
Exposure to X-rays performed on the thyroid during childhood
Have a pre-existing thyroid condition like thyroiditis or Hashimoto's thyroiditis
A family history of thyroid nodules
Age is 60 years or older
Thyroid nodules are more common in women. When they develop in men, they're more likely to be cancerous.
Prognosis of Thyroid Nodule
Benign thyroid nodules are not life-threatening, and most do not require any treatment. Only timely monitoring is usually enough. The outlook for thyroid cancer is based on the type of cancer. After treatment, the prognosis is good for most common kinds of thyroid cancer. In cases of surgical excision of the thyroid gland, the patient is advised to take medicines to maintain the supply of thyroid hormones in the body.
Review
Reviewed By Dr Sumit Mrig, Associate Director and Head ENT (Ear Nose Throat) on 1 July 2024.
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