Goiter (Enlarged Thyroid)

What the thyroid does

The thyroid is a butterfly-shaped gland that wraps around the front of the windpipe. It uses iodine from food to make thyroid hormones, which control metabolism, energy, heart rate and body temperature. The pituitary gland controls it with thyroid-stimulating hormone (TSH).

A goiter forms when the thyroid is stimulated to grow (by TSH or antibodies), is inflamed, or develops nodules.

Causes of goiter

Risk factors

• living in areas with low iodine in soil and food, or not using iodized salt
• female sex; goiter is several times more common in women
• age over 40
• family history of thyroid disease
• pregnancy and menopause
• radiation exposure to the neck

Symptoms

Many goiters cause no symptoms and are found during a check-up or scan. When present, symptoms include:

• a visible swelling at the base of the neck, more noticeable when swallowing
• a feeling of tightness or a lump in the throat
• difficulty swallowing
• cough, hoarseness or a change in voice
• breathlessness or noisy breathing, especially lying down, if the goiter presses on the windpipe or extends behind the breastbone (substernal goiter)

If thyroid hormone levels are abnormal:

• Underactive (hypothyroidism): tiredness, weight gain, feeling cold, constipation, dry skin, low mood
• Overactive (hyperthyroidism): weight loss, racing heart, tremor, sweating, anxiety, heat intolerance, frequent bowel movements

Diagnosis

1. Physical examination: feeling the size, texture and nodules of the gland while you swallow
2. Blood tests: TSH, free T4 and sometimes T3, plus thyroid antibodies (TPO antibodies for Hashimoto's, TSH receptor antibodies for Graves')
3. Thyroid ultrasound: measures size and shows nodules, rating their risk using features such as solid content, calcifications and irregular edges
4. Fine-needle aspiration biopsy: for nodules with suspicious features or above size thresholds, to rule out thyroid cancer
5. Radioactive iodine uptake scan: if thyroid hormone is high, to find "hot" overactive areas
6. CT scan or breathing tests: for large goiters extending into the chest

Treatment

Treatment depends on the size, cause, symptoms and thyroid function:

• Observation: small goiters with normal thyroid function and benign nodules may simply be monitored with periodic ultrasound and blood tests
• Iodine: for iodine deficiency, iodized salt or supplements (not for goiters caused by other conditions, where extra iodine can be harmful)
• Levothyroxine: treats hypothyroidism and may slow growth of some goiters
• Antithyroid medicines (methimazole, propylthiouracil) for Graves' disease or toxic nodules
• Beta-blockers to control symptoms of hyperthyroidism
• Radioactive iodine: shrinks overactive goiters and can reduce the size of large nontoxic goiters in some people
• Surgery (thyroidectomy): removing part or all of the thyroid for goiters causing pressure symptoms, suspicious or cancerous nodules, large goiters extending into the chest, or cosmetic concerns. After total thyroidectomy, lifelong thyroid hormone replacement is needed
• Radiofrequency ablation of selected benign nodules causing symptoms

Surgery risks

These include hoarseness from injury to the recurrent laryngeal nerve, and low calcium from damage to the parathyroid glands. Both are uncommon with experienced surgeons.

Prevention

Using iodized salt prevents iodine-deficiency goiter. Pregnant and breastfeeding women need more iodine; the American Thyroid Association recommends a prenatal vitamin containing 150 micrograms of iodine daily. Avoid high-dose iodine or kelp supplements, which can trigger thyroid problems.

Frequently asked questions

What causes a goiter?

Worldwide, iodine deficiency is the main cause. In countries with iodized salt, such as the US, goiters are more often caused by Hashimoto's thyroiditis, Graves' disease, thyroid nodules, thyroiditis and, less commonly, thyroid cancer or medicines such as lithium.

What are the symptoms of a goiter?

Many goiters cause only a visible neck swelling. Larger ones can cause tightness, difficulty swallowing, cough, hoarseness or breathing problems. If thyroid hormone levels are abnormal, there may be symptoms of an underactive or overactive thyroid.

Is a goiter serious?

Most goiters are benign and not dangerous. They need evaluation because a small percentage contain cancer, and large goiters can compress the windpipe or esophagus. Blood tests and an ultrasound usually show whether treatment is needed.

Can a goiter go away on its own?

Goiters caused by thyroiditis or pregnancy may shrink over time. Iodine-deficiency goiters can shrink with iodine replacement, especially in children. Most multinodular goiters and those from Hashimoto's do not disappear but may stay stable for years.

Does a goiter mean I have thyroid cancer?

No. Most goiters, including nodular ones, are benign. Ultrasound features help identify nodules that need a fine-needle biopsy, which can confirm or rule out cancer.