OVERVIEW

What is goiter?

A normal thyroid lobe is 2–2.5 cm wide, 4–5 cm tall, and 1–1.5 cm thick, while the thyroid isthmus is approximately 2 cm in length and width.

Goiter refers to abnormal enlargement of the thyroid gland due to various causes, which may or may not be accompanied by thyroid dysfunction. Common causes include iodine deficiency, intake of goitrogenic substances, and genetic defects. Treatment varies depending on the underlying cause.

What are the types of goiter?

1. Based on thyroid function, it can be classified as:

• Simple goiter: Also known as "nontoxic goiter," it refers to thyroid enlargement without thyroid dysfunction.
• Toxic goiter: Refers to thyroid enlargement accompanied by hyperthyroidism.

2. Based on etiology, it can be classified as:

• Endemic goiter: Related to iodine deficiency, commonly known as "big neck disease," mainly seen in mountainous areas far from the sea and at high altitudes.
• Sporadic goiter: Less related to iodine deficiency but associated with increased demand for thyroid hormones, such as adolescent goiter, pregnancy goiter, lactation goiter, and menopausal goiter.

3. Based on morphology, it can be classified as:

• Diffuse goiter: The entire thyroid gland is uniformly enlarged, commonly seen in the early stages of goiter.
• Nodular goiter: Thyroid enlargement with multiple nodules, often seen in the late stages of goiter.

Understanding the classification of goiter helps doctors develop appropriate treatment plans.

SYMPTOMS

What are the manifestations of goiter?

• The main symptom noticeable to patients is neck thickening, with some possibly experiencing mild neck pain or discomfort.

• In cases of significant thyroid enlargement, compression symptoms may occur, such as difficulty breathing, coughing, choking sensation, snoring, sleep apnea, swallowing difficulties, or hoarseness.

• If accompanied by hyperthyroidism, symptoms may include heat intolerance, excessive sweating, increased hunger, weight loss, palpitations, hand tremors, irritability, insomnia, menstrual irregularities, and frequent bowel movements.

• If accompanied by hypothyroidism, symptoms may include cold intolerance, fatigue, lethargy, excessive sleepiness, decreased appetite, weight gain, swelling, constipation, and menstrual irregularities.

CAUSES

What are the causes of goiter?

There are multiple causes of goiter, including:

• Iodine deficiency: Iodine deficiency is the main cause of endemic goiter. Iodine is essential for thyroid hormone synthesis. When iodine is insufficient, reduced thyroid hormone production triggers the pituitary gland to secrete thyroid-stimulating hormone (TSH), stimulating thyroid hyperplasia and leading to compensatory thyroid enlargement. With the use of iodized salt, iodine-deficiency-induced goiter has become rare.

• Goitrogenic substances: Goitrogenic foods include cruciferous vegetables (e.g., cabbage), cassava, and excessively fluoridated water. Goitrogenic drugs include antithyroid medications like methimazole (e.g., pregnant women with hyperthyroidism taking antithyroid drugs may cause fetal goiter), lithium carbonate, and amiodarone.

• Genetic defects or mutations: These may cause enzyme deficiencies, thyroglobulin defects, or thyroid hormone receptor defects, impairing thyroid hormone synthesis or function and leading to compensatory thyroid enlargement.

• Increased demand for thyroid hormone: During puberty, pregnancy, lactation, or menopause, the body's need for thyroid hormone rises. To produce more hormones, the thyroid may enlarge compensatorily. This is a physiological response, not a disease.

• Certain thyroid disorders: Conditions like Graves' disease, Hashimoto's thyroiditis, nodular goiter, and thyroid tumors can all cause thyroid enlargement.

Is goiter hereditary?

Some goiters are hereditary, such as those caused by genetic defects or mutations.

Others, though not hereditary, may occur frequently within families due to shared environmental factors, like endemic goiter.

Additionally, if a mother has thyroid disease or takes antithyroid drugs during pregnancy, the infant may develop goiter, but this is not due to heredity.

DIAGNOSIS

How to determine if there is a goiter?

An obvious goiter can be observed with the naked eye, and an experienced doctor can confirm it by palpating the thyroid gland.

A subtle goiter requires a B-ultrasound examination to confirm.

What tests are needed if a goiter is found?

• Thyroid B-ultrasound: Can confirm the presence of a goiter and preliminarily determine its cause.

• Thyroid function tests: Require blood tests, including TSH (thyroid-stimulating hormone), T4 (thyroxine), T3 (triiodothyronine), etc., mainly to assess hyperthyroidism or hypothyroidism and guide further treatment.

• Thyroid antibody tests: Require blood tests, including TRAb (TSH receptor antibody), TPOAb (thyroid peroxidase antibody), TgAb (thyroglobulin antibody), etc., to help determine the cause of the goiter.

• Urinary iodine test: Can roughly assess iodine deficiency. Doctors usually determine iodine deficiency through medical history, and urinary iodine is only an auxiliary test.

• Depending on the condition, other tests such as thyroid iodine uptake test, radionuclide imaging, or fine-needle aspiration cytology may also be used.

TREATMENT

Which department should I see for goiter?

Generally, endocrinology should be prioritized, and thyroid surgery may also be required depending on the situation.

How is goiter treated?

1. Address the cause:

• If it is physiological goiter (e.g., during puberty or pregnancy), no medication is needed. Simply consume iodine-rich foods like iodized salt, kelp, or seaweed.
• If caused by iodine deficiency, iodine supplements such as potassium iodide or Lugol's solution are required.
• If caused by thyroid diseases like Graves' disease, the primary condition must be treated.

2. Thyroid hormone therapy:

This can "reduce the pressure on the thyroid to produce hormones," shrinking the compensatory enlargement.

3. Surgical removal and radioactive ¹³¹I therapy:

If the goiter is particularly large or causes compression symptoms, partial thyroidectomy or radioactive ¹³¹I therapy may be needed to shrink the thyroid.

Are there side effects to taking thyroid hormones?

If taken without hypothyroidism, thyroid hormone therapy for goiter may cause side effects like insomnia, heart disease, or osteoporosis. Therefore, doctors should weigh the risks and benefits, and patients should follow up as advised to adjust the dosage and minimize side effects.

If goiter is accompanied by hypothyroidism, thyroid hormone therapy at the correct dose—maintaining normal thyroid function—typically has no side effects.

When does goiter require surgery?

Surgery may be considered in the following cases:

• Large or substernal goiter: These often cause compression symptoms, affecting quality of life.
• Goiter with hyperthyroidism: Usually treated first with medication or radioactive ¹³¹I; surgery is considered if these fail or are unsuitable.
• Suspected malignancy in nodular goiter: Requires prompt surgery.

Some patients without these conditions may opt for surgery for cosmetic reasons, which doctors may consider after evaluating risks and benefits.

Can goiter fully recover?

If treated early and properly, short-term goiter may fully resolve. Long-standing cases, especially nodular goiter, are unlikely to return to normal completely.

DIET & LIFESTYLE

What should people with goiter pay attention to in their diet?

If the goiter is caused by iodine deficiency, dietary considerations include:

• Iodine supplementation: Consume more iodine-rich foods, including iodized salt, kelp, seaweed, algae, and other seafood.

• Moderate selenium intake: Studies show that iodine deficiency is more likely to cause goiter in selenium-deficient conditions. Therefore, selenium-rich foods can be consumed, such as selenium-enriched rice, corn, wheat, seafood, liver, mushrooms, and eggs.

• Limit goitrogenic foods: Such as cruciferous vegetables, including rapeseed, shepherd's purse, radish, cauliflower, broccoli, cabbage, and Chinese cabbage. The isothiocyanates in cruciferous vegetables inhibit iodine absorption by the thyroid, affecting thyroid hormone synthesis and leading to goiter. However, this effect only occurs when consuming large amounts of raw cruciferous vegetables. Eating small amounts or cooking them thoroughly minimizes the impact.

PREVENTION

Can goiter be prevented? How to prevent it?

Goiter caused by iodine deficiency can be prevented.

Except for a few areas with high water iodine levels, iodine deficiency is widespread in China. Therefore, except for residents in high water iodine areas, others can prevent iodine deficiency diseases like goiter by consuming iodized salt.