Thyroid Goiter (Enlarged Thyroid)

What a goiter is

A normal thyroid is about the size of two thumbs and usually cannot be seen. A goiter is any enlargement, from a slight fullness found on examination to a large visible swelling. Some goiters grow downward behind the breastbone (substernal or retrosternal goiter) and may press on the windpipe without being very visible.

Types of goiter

Causes

• iodine deficiency: the leading cause globally; rare in the US because of iodized salt, but can occur with restrictive diets
• Hashimoto's thyroiditis: autoimmune inflammation, the most common cause of hypothyroidism in the US
• Graves' disease: autoimmune stimulation of the thyroid causing overactivity
• thyroid nodules and multinodular goiter
• pregnancy: hCG and increased iodine needs can enlarge the thyroid
• thyroiditis after pregnancy or viral infection
• medicines: lithium, amiodarone
• goitrogens: very large amounts of certain foods (raw cassava, raw cruciferous vegetables) only with low iodine intake
• thyroid cancer: an uncommon cause of a lump

Symptoms

Many goiters cause no symptoms. Possible symptoms:

• visible swelling at the base of the neck
• tightness in the throat or a lump in the throat sensation
• difficulty swallowing
• coughing
• hoarseness
• shortness of breath or noisy breathing, especially lying flat
• facial flushing or swelling of neck veins when raising the arms (large substernal goiters)

If thyroid function is abnormal:

• hyperthyroidism: weight loss, racing heart, tremor, anxiety, heat intolerance, sweating, frequent stools
• hypothyroidism: tiredness, weight gain, feeling cold, constipation, dry skin, low mood

Diagnosis

• physical exam: size, texture, nodules, tenderness and lymph nodes
• blood tests: TSH first; free T4 and T3; thyroid antibodies (TPO for Hashimoto's, TSH receptor antibodies for Graves')
• thyroid ultrasound: size, nodules and features that suggest cancer risk
• fine-needle aspiration biopsy of nodules with suspicious ultrasound features
• radioactive iodine uptake scan when hyperthyroidism is present
• CT scan or breathing tests for large or substernal goiters affecting the airway

Treatment

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

• watchful waiting: small goiters with normal thyroid function and no worrying features
• iodine: for iodine deficiency, through iodized salt or supplements under medical guidance
• levothyroxine: treats hypothyroidism; it is not routinely used to shrink goiters with normal function
• antithyroid medicines (methimazole), radioactive iodine or surgery for hyperthyroidism
• radioactive iodine can shrink some nontoxic multinodular goiters in people who cannot have surgery
• surgery (thyroidectomy): for goiters causing pressure symptoms, cosmetic concerns, suspected cancer, or overactivity not controlled otherwise. After total thyroidectomy, lifelong thyroid hormone replacement is needed
• radiofrequency ablation for selected benign nodules causing symptoms

Outlook

Most goiters are benign and manageable. Monitoring with periodic ultrasound and thyroid tests is usually enough for small goiters. Treatment of underlying thyroid disease controls symptoms well.

Prevention

In the US, iodized salt, dairy, eggs and seafood provide enough iodine for most people. Pregnant and breastfeeding women need more iodine; the American Thyroid Association recommends a prenatal vitamin containing iodine. Avoid high-dose iodine or kelp supplements unless advised, as excess iodine can also cause thyroid problems.

Frequently asked questions

What causes a goiter?

Worldwide, iodine deficiency is the most common cause. In the US, goiters are usually caused by Hashimoto's thyroiditis, Graves' disease or multinodular goiter. Pregnancy, thyroiditis and some medicines can also enlarge the thyroid.

What are the symptoms of a goiter?

Many goiters cause no symptoms other than neck swelling. Larger ones can cause a tight feeling in the throat, difficulty swallowing or breathing, coughing and hoarseness. If thyroid function is abnormal, symptoms of an overactive or underactive thyroid may occur.

Is a goiter dangerous?

Usually not. Most goiters are benign. A large goiter can compress the windpipe or esophagus, and some nodules need testing to rule out cancer. Rapid growth, hoarseness or breathing problems need prompt assessment.

Can a goiter go away on its own?

Some goiters related to pregnancy or temporary thyroiditis shrink on their own. Goiters from iodine deficiency may shrink with iodine. Most long-standing goiters remain, and treatment depends on symptoms and thyroid function.