This refers to a swelling in the neck caused by an abnormal enlargement of the thyroid gland. The thyroid is a butterfly-shaped gland situated at the base of the neck, just beneath the Adam’s apple and in front of the trachea.

While a goiter is typically painless, a significantly large goiter can induce coughing and make swallowing or breathing difficult. The enlargement of the thyroid gland can also lead to swelling of the neck or larynx (voice box).

Dietary iodine sources include:

• Seafood

• Plant foods cultivated in iodine-rich soils

• Cow’s milk

Types of goiter

There are two distinct types of goiters:

• Diffuse small goiter: In this type, the entire thyroid gland enlarges uniformly to a considerable size and feels smooth to the touch.

• Nodular goiter: Here, specific sections or nodules within the thyroid gland enlarge, resulting in a lumpy texture upon palpation.

Sample anatomy & physiology.

The endocrine system encompasses all glands in the body responsible for producing hormones. These chemical messengers are crucial for ensuring proper bodily function. If the endocrine system is unhealthy, an individual may experience issues with development during puberty, fertility, or stress management.

Glands that constitute the endocrine system:

Brain

• Hypothalamus: This gland connects the endocrine system to the nervous system. It signals the pituitary gland to either initiate or cease hormone production.

• Pituitary gland: Often referred to as the master gland of the endocrine system, it secretes hormones such as growth hormones, prolactin, and luteinizing hormone, which stimulates estrogen production in women and testosterone in men.

• Pineal gland: Produces melatonin, a hormone that aids the body in preparing for sleep.

Neck

• Thyroid: Responsible for producing thyroid hormones, which regulate the body’s metabolic rate.

  • Hypothyroidism: An underactive thyroid can lead to a slow heart rate, constipation, or weight gain.

  • Hyperthyroidism: An overactive thyroid may result in a rapid heartbeat, diarrhea, and unintentional weight loss.

• Parathyroid: Four small glands located behind the thyroid, vital for bone health by controlling calcium and phosphorus levels.

Lungs

• Thymus: Produces white blood cells called T-lymphocytes, which combat infections within a child’s immune system. This gland typically shrinks during puberty.

Behind the Stomach

• Pancreas: Functions as part of both the endocrine and digestive systems. It produces enzymes that break down food and the hormone insulin, which regulates blood sugar levels.

Pelvic

• Woman – ovaries: Produce estrogen and progesterone. These hormones are essential for breast development during puberty, regulation of the menstrual cycle, and supporting pregnancy.

• Man — testes: Produce testosterone, which promotes the growth of facial and body hair during puberty, enlargement of the penis, and sperm production.

Symptoms

Not all goiters present with noticeable signs and symptoms. When symptoms do manifest, they may include:

• A visible swelling at the base of the neck

• A sensation of tightness in the throat

• Coughing

• Hoarseness

• Difficulty swallowing

• Difficulty breathing

Causes

The thyroid gland produces two primary hormones:

1. Thyroxine (T4​)

2. Triiodothyronine (T3​)

These hormones circulate in the bloodstream and play a role in body metabolism. They regulate the rate at which the body utilizes fats and carbohydrates, help control body temperature, influence heart rate, and assist in regulating protein production. The thyroid gland also produces calcitonin, a hormone that regulates the amount of calcium in the blood.

The pituitary gland and the hypothalamus control the rate at which these hormones are produced and released. The process begins when the hypothalamus signals the pituitary gland to produce thyroid-stimulating hormone (TSH). Consequently, the thyroid gland produces T3​ and T4​ based on the amount of TSH it receives from the pituitary gland.

Having a goiter does not necessarily indicate abnormal thyroid gland function. Even when enlarged, your thyroid may produce normal quantities of hormones. However, it might also produce an excessive or insufficient amount of T3​ and T4​.

• Iodine deficiency: This is the most common cause of goiter. Iodine, crucial for thyroid hormone production, is found in seawater. The thyroid gland enlarges in an attempt to acquire more iodine. Iodine deficiency can be exacerbated by a diet rich in hormone-inhibiting foods such as cabbage.

• Hyperthyroidism: Occurs when the thyroid gland produces an excessive amount of thyroid hormone. In such cases, antibodies mistakenly produced by the immune system attack the thyroid gland, prompting it to produce excess thyroxine.

  • Symptoms:

    • Weight loss

    • Increased appetite

    • Heat intolerance

    • Hair loss

    • Fatigue

    • Increased sweating

    • Palpitations

    • Nervousness

• Hypothyroidism: A goiter can also result from an underactive thyroid. This is also an autoimmune disorder that causes the gland to produce too few hormones. Sensing a low hormone level, the pituitary gland stimulates the thyroid, which then causes it to enlarge.

  • Symptoms:

    • Weight gain

    • Constipation

    • Cold intolerance

    • Dry and scaly skin

    • Forgetfulness

• Multinodular goiter: Characterized by the development of several fluid-filled lumps, or nodules, on both sides of the thyroid, leading to significant enlargement of the gland.

• Solitary thyroid nodules: Involves the development of a single nodule in one part of the thyroid gland. Most of these nodules are benign (non-cancerous) and do not progress to cancer.

• Thyroid cancer: This is considerably less common than benign thyroid nodules. A biopsy can be performed to diagnose this condition.

• Pregnancy: A hormone produced during pregnancy (Human Chorionic Gonadotropin – HCG) may cause a slight enlargement of the gland.

• Inflammation: Thyroiditis is an inflammatory condition that can cause pain and swelling of the thyroid. It may also lead to an overproduction or underproduction of thyroxine.

• Smoking: Thiocyanate present in tobacco smoke interferes with iodine absorption.

RISK FACTORS

• Lack of dietary iodine.

• Being female: Females are more susceptible to thyroid disorders and are more likely to develop goiter.

• Age: More common after the age of 40.

• Medical history: A personal or family history of autoimmune disease increases the risk.

• Pregnancy and menopause.

• Certain medications: Some medical treatments, including the heart drug amiodarone and the psychiatric drug lithium, increase the risk.

• Radiation exposure: Exposure to radiation in the neck or chest area can lead to enlargement of the gland.

Diagnosis

1. Physical examination: Examination of the swelling will assist the physician in diagnosing goiter (determining if it is diffuse or nodular).

2. Thyroid function test: This involves testing the levels of thyroid hormones in the blood, such as thyroxine, triiodothyronine, and TSH.

3. Blood tests: These are performed to detect thyroid antibodies; elevated levels can help the doctor identify the cause of an overactive thyroid.

4. Ultrasound: An ultrasound scan of the neck or a radioactive iodine uptake scan may be performed.

Management

The management of goiter depends on whether the patient is experiencing hyperthyroidism or hypothyroidism.

Hypothyroidism

If a patient is diagnosed with hypothyroidism, treatment involves using synthetic (man-made) hormones to replicate normal thyroid function. This is known as hormone therapy. For example, Levothyroxine is typically taken orally once a day.

Hyperthyroidism

An overactive thyroid gland can be treated with thionamides. Thionamides are drugs that help reduce the amount of thyroid hormones produced by the thyroid gland.

Radioactive iodine

This is another treatment for an overactive thyroid gland, taken orally. When the iodine reaches the thyroid gland, it destroys thyroid cells and reduces the size of the goiter. However, this treatment may cause the thyroid gland to become underactive.

Iodine supplements

The regular consumption of iodized salt provides protection against goiter caused by hypothyroidism.

Surgery

If the goiter interferes with breathing or swallowing and has not responded to other forms of treatment, surgery may be required to remove part or the entire gland.

Complications

Some goiters that do not cause physical or cosmetic issues are not a concern. However, large goiters can make breathing or swallowing difficult and may cause a cough and hoarseness.