Goiter, an enlargement of the thyroid gland

The thyroid gland is a gland in the body that produces thyroid hormones using iodine as one of its components. These hormones are then released into the bloodstream and play a crucial role in stimulating the metabolism of cells throughout the body and are necessary for the body's growth and development.

Goiter can be classified into different types based on the pattern of thyroid gland enlargement:

1. Diffuse goiter: This refers to a condition where the thyroid gland is enlarged uniformly.

Solitary thyroid nodule: This refers to a condition where there is an enlargement of a single, palpable nodule within the thyroid gland, while the rest of the gland appears normal.

Multinodular goiter: This refers to a condition where there are multiple nodules within the thyroid gland, causing it to appear lumpy.

Goiter can also be classified based on the presence or absence of symptoms:

       2. Toxic goiter: This refers to a condition where there is excessive production and secretion of thyroid hormones, causing symptoms such as tremors, fatigue, weight loss, and others.

       3. Simple goiter: This refers to a condition where there is thyroid gland enlargement without any toxic symptoms.

What is the thyroid gland?

The thyroid gland is a type of gland without ducts located in the front of the neck, positioned in front of the trachea. It weighs approximately 20 grams and is divided into two lobes, left and right, connected in the center by a part of the gland called the isthmus. Each lobe is about 5x2x2 cm in size. The thyroid gland is covered with muscle tissue, and when it is not enlarged, it cannot be seen.

The thyroid gland is responsible for producing thyroid hormones using iodine as one of its components. These hormones are then released into the bloodstream. These hormones stimulate the metabolism of cells throughout the body, and they are necessary for the growth and development of the body.

The cause:

Simple goiter is mostly caused by a lack of iodine in the body. It may occur when the body needs more thyroid hormone, such as during adolescence or pregnancy, after taking certain substances or medications. (Initially, the thyroid gland will enlarge normally, but later it may become a single nodule or a multi-nodular mass.) Single nodules and multi-nodular masses of the thyroid gland may be caused by iodine deficiency, cysts, thyroiditis, benign tumors or cancer. Toxic thyroid nodules may occur due to Graves' disease, an overactive benign nodule (toxic adenoma), or long-standing nodules (toxic multinodular goiter). Toxic thyroid syndrome may occur due to Graves' disease, benign nodules, or toxic multinodular goiter.

Signs and symptoms

There were no symptoms other than an enlarged thyroid gland.

Symptoms related to toxic thyroid gland are easy fatigue, heart palpitations, trembling hands, weight loss despite increased appetite, excessive sweating, heat intolerance, easy irritability, insomnia, weakness of muscles, possible menstrual changes, diarrhea, and changes in the eyes such as protruding eyeballs. Painful swelling may occur in the thyroid gland due to inflammation or bleeding in the gland. Symptoms from pressure on adjacent organs can occur in cases where the swelling is large, such as difficulty swallowing (pressure on the esophagus) and breathing difficulties (pressure on the trachea). Symptoms from the spread of the lump may include hoarseness, due to the spread to the nerve that supplies the vocal cords, and if this symptom is present, it is often due to cancer.

The symptoms of cancer metastasis may include swollen lymph nodes in the neck or bone pain.

Importance

Enlarged thyroid gland is a common condition. It is found that approximately 4-7% of the population will have nodules in the thyroid gland (about half will be found as single nodules). It is more common in women than men. A single nodule in the thyroid gland has a chance of being cancerous, about 5-10%.

Toxic thyroid gland is less likely to be cancerous, about 1%, and is more likely to occur in the following groups:

• History of previous radiation exposure to the head and neck in childhood (if nodules are present, the chance of cancer is about 30-40%)
• Family history of thyroid cancer
• Thyroid nodules in men are more likely to be cancerous than in women (although thyroid nodules are more common in women)
• Age younger than 20 years or older than 60 years
• Rapidly growing nodules or those causing hoarseness, difficulty breathing, or swallowing
• Hard nodules that are attached to adjacent organs or have spread to nearby lymph nodes

The Thyroid function test helps determine if there is toxicity in the thyroid gland.

Fine needle aspiration biopsy, which involves using a needle to extract cells, is the most important method for diagnosing whether a thyroid nodule is cancerous or not.

Ultrasound is used to determine the size and boundaries of the nodule, and to differentiate between cystic and solid nodules. Cystic nodules have a lower chance of being cancerous.

Radioisotope scan helps determine whether the thyroid nodule is functioning normally or not (referred to as a hot nodule or cold nodule, respectively). Typically, cancerous nodules function less than normal.

CT scan is used in cases where the nodule is large or if there is compression of adjacent organs.

When you go to see a doctor, what will they do?

Medical history includes age and gender, duration of symptoms, changes in the size of the nodule (growing rapidly or slowly), pain at the site of the nodule, symptoms of fatigue, palpitation, suspicious family or personal cancer history, hoarseness, difficulty breathing or swallowing. Physical examination includes a general examination and observation of the nodule while swallowing. The physician will examine the size, boundaries, consistency, enlargement of lymph nodes, and signs and symptoms related to thyroid toxicity.

Further special examinations are conducted to differentiate between toxic and non-toxic thyroid symptoms and to determine if the nodule is cancerous.

Treatment is given according to the diagnosed cause.

Guidelines for Treatment

The diagram summarizes the guidelines for treatment for solitary thyroid nodule and multinodular goiter

Treatment options

Solitary thyroid nodule:

1. Surgery: If the nodule is confirmed or suspected to be cancerous, if the nodule is large, presses on adjacent organs or if the patient wants to remove it for cosmetic reasons.
2. Observation: If the nodule is not cancerous, it may not require surgery. The patient can be monitored or given thyroid hormone medication for a period of time.

Toxic thyroid nodule:

1. Medication: Antithyroid medication is used to control symptoms of toxicity. The duration of medication is about 1-2 years. If symptoms persist, alternative treatments may be considered.
2. Surgery: Used for cases where the nodule is very large or if there are contraindications to radiation therapy.
3. Radioactive iodine therapy: The radioactive substance destroys the overactive thyroid cells and resolves the toxic symptoms.

Source: Thaiclinic.com